A review on various electrochemical techniques for heavy metal ions detection with different sensing platforms

Biosensors and Bioelectronics 94 (2017) 443–455

Contents lists available at ScienceDirect

Biosensors and Bioelectronics journal homepage: www.elsevier.com/locate/bios

A review on various electrochemical techniques for heavy metal ions detection with different sensing platforms

MARK

⁎

BabanKumar Bansoda, , Tejinder Kumarb, Ritula Thakurc, Shakshi Ranac, Inderbir Singha a b c

CSIR-Central Scientific Instruments Organisation, Chandigarh 160030, India IISER, Indian Institute of Science Education and Research, Mohali, Punjab 140306,India NITTTR, National Institute of Technical Teachers Training and Research, Chandigarh 160019, India

A R T I C L E I N F O

A BS T RAC T

Keywords: Heavy metal ions Electrochemical techniques Metallic interface Nanomaterials Biomaterials

Heavy metal ions are non-biodegradable and contaminate most of the natural resources occurring in the environment including water. Some of the heavy metals including Lead (Pb), Mercury (Hg), Arsenic (As), Chromium (Cr) and Cadmium (Cd) are considered to be highly toxic and hazardous to human health even at trace levels. This leads to the requirement of fast, accurate and reliable techniques for the detection of heavy metal ions. This review presents various electrochemical detection techniques for heavy metal ions those are user friendly, low cost, provides on-site and real time monitoring as compared to other spectroscopic and optical techniques. The categorization of different electrochemical techniques is done on the basis of different types of detection signals generated due to presence of heavy metal ions in the solution matrix like current, potential, conductivity, electrochemical impedance, and electrochemiluminescence. Also, the recent trends in electrochemical detection of heavy metal ions with various types of sensing platforms including metals, metal films, metal oxides, nanomaterials, carbon nano tubes, polymers, microspheres and biomaterials have been evoked.

1. Introduction Heavy metal ions (HMI) are one of the micropollutants that represent a growing environmental problem and have affected various components of environment including terrestrial as well as aquatic biota. Major sources of these heavy metal ions are cosmetics and their by-products, fertilizers and other chemicals generated from industrial or household waste (Callender, 2004; Roy, 2010). These HMI do not decompose and have a tendency to accumulate in living organisms, causing various diseases and disorders to the nervous, immune, reproductive and gastrointestinal systems (Afkhami et al., 2013a; Tag et al., 2007; Turdean, 2011). Once let out in the environment, these HMI continue to exist for decades or even centuries as these are nonbiodegradable (Gong et al., 2016). Among various heavy metals, lead (Pb), cadmium (Cd), mercury (Hg), chromium (Cr) and arsenic (As) are highly toxic (Cui et al., 2015; Pujol et al., 2014; Gumpu et al., 2015). Even small doses of these highly toxic metals can lead to serious problems on environment and human health (Tag et al., 2007; Gumpu et al., 2015; Array and Merkoci, 2012). Human beings are mainly exposed to these metal ions from air, water and food with fish being the major source of mercury exposure (Pujol et al., 2014; Maria, 2011; Musarrat et al., 2011; Prabhakar et al., 2012). Heavy metals are also ⁎

considered as one of the most dangerous water pollutants, extremely destructive for nature and injurious to human health (Guo et al., 2016a; Wanekaya, 2011; Kim et al., 2012; Lin et al., 2011; Aragay et al., 2011a; Bernalte et al., 2011). The detection of these heavy metal ions in natural and drinking water and determining their quantities is of paramount importance. Several international organizations like World Health Organization (WHO), Joint Food and Agricultural Organization (FAO), the US Environmental Protection Agency (EPA), Centre for Disease Control (CDC) and the European Union have included heavy metals as the priority substances to be monitored and have set certain permissible limits for their concentrations in water following the environmental quality standards (EQS) (Gumpu et al., 2015; WHO, 2011; US, 2009; Directive, 2013; Standard methods for the examination of water and wastewater, 2012). This requires development of highly sensitive and selective methods for determination of trace levels subparts per billion, ppb) of these toxic heavy metal ions in various complex matrices like biological samples (blood, serum, saliva, etc.), natural and waste water, food, air and soil. Highly sensitive spectroscopic techniques like atomic absorption spectroscopy (AAS) (Gong et al., 2016; Array and Merkoci, 2012; Afkhami et al., 2013b; Barbosa et al., 1999; Trindade et al., 2015; Kenawy et al., 2000; a to z; Pohl, 2009), inductively coupled plasma

Corresponding author. E-mail addresses: [email protected] (B. Bansod), [email protected] (T. Kumar), [email protected] (R. Thakur), [email protected] (S. Rana), [email protected] (I. Singh). http://dx.doi.org/10.1016/j.bios.2017.03.031 Received 2 January 2017; Received in revised form 5 March 2017; Accepted 14 March 2017 Available online 18 March 2017 0956-5663/ © 2017 Elsevier B.V. All rights reserved.

Biosensors and Bioelectronics 94 (2017) 443–455

B. Bansod et al.

materials play a vital role in sensitive and selective determination of HMI. Earlier, mercury and carbon was employed most frequently as interface material for construction of these electrodes. However, due to its mechanical instability and toxicity, dropping mercury electrodes and hanging mercury drop electrodes are unsuitable for automated analysis of HMI recently. A lot of research is ongoing in the field of designing chemically modified electrodes using various interface materials including electrochemical biosensors, nanomaterials, polymers, metal oxides, carbon nanotubes, and many more.

mass spectroscopy (ICP-MS) (Gong et al., 2016; Silva et al., 2009; Caroli et al., 1999; Wang et al., 2015), X-ray Fluorescence Spectrometry (XRF) (Sitko et al., 2015), Neutron activation analysis (NAA) and inductively coupled plasma-optical emission spectrometry (ICP-OES) (Losev et al., 2015) are employed for detection of heavy metals in complex matrices. These techniques are versatile in terms of simultaneous determination of heavy metal ions concentration for a large range of elements. These techniques also offer very low detection limits in femtomolar range (Pujol et al., 2014). However, these spectroscopic techniques are very expensive and require trained personnel to work on the complex equipments and require multi sample preparation involving difficult analytical procedures. Also, these techniques are only suitable for quantitative analysis and needed to be coupled with other chromatographic techniques for performing metal ion speciation (Feldmann et al., 2009). This could lead to the risk of sample changes while storage and handling. Optical techniques like spectrophotometric measurements are also employed for detection of heavy metal ions (Array and Merkoci, 2012). These optical methods again involves costly and complex equipment with lasers, photo detectors, etc. that require high precision and high power operations, again not suited for in-field applications. Therefore, development of rapid, low cost, simple and reliable techniques suitable for in-situ and on-time measurements of heavy metal ions is an ongoing area of research (Cui et al., 2015; Pujol et al., 2014; Array and Merkoci, 2012). Electrochemical techniques on a contrary are more economic, userfriendly, reliable and suitable for in-field applications. These electrochemical techniques allow simple procedures and well suited to fabricate on small circuits in the form of portable devices for in-situ monitoring of contaminated samples. These techniques are also fast in terms of short analytical time as compared to other spectroscopic techniques allowing on-line monitoring of water samples (Pujol et al., 2014). However, these electrochemical techniques offer lower sensitivity and Limits of detection (LOD) as compared to other spectroscopic and optical techniques and require developments in the design to improve its performance in detection of heavy metal ions. Various electrochemical techniques are coupled with different biosensing electrodes for enhancing their sensitivity and limits of detection by modifying the electrode material. This paper reviews various electrochemical techniques employed for detection of HMI in water samples and recent advances in the development of various interface materials for modifying electrodes employed in these techniques.

3. General experimental setup for electrochemical detection of HMI General experimental setup for electrochemical detection of HMI usually consists of an electrolytic cell consisting of an ionic conductor (an electrolyte) and an electronic conductor (an electrode) (Bard and Faulkner, 1944). In this case, an aqueous solution consisting of HMI acts as the electrolyte. The cell potential is measured at the interface of the electrode and electrolyte solution. Various half reactions take place in the electrolytic cell and one of the half reactions of interest is usually at the working electrode (WE). The other electrode with respect to which the cell potential is measured is termed as reference electrode (RE). A general electrochemical experiment uses an external power supply to provide an excitation signal and measure the response function in the chemical solution considering various system variables to be kept constant as represented in Fig. 1. For a three electrode cell arrangement, the third electrode is referred to as the counter electrode (CE). The current is usually passed between the WE and CE.A general three electrode cell setup for electrochemical detection of heavy metal ions in aqueous solution is represented in Fig. 2 (Cui et al., 2015). This setup has three electrodes as mentioned above placed in an electrolytic cell with WE modified with different interface materials as platform for heavy metal ions. In this electrochemical setup, the current is generally passed between the WE and CE. CE is placed in a separate section from the WE by some glass separators and its material is chosen such that it doesn't affects the WE. The potential is measured between the WE and RE with some high input impedance device in order to prevent any current drawn from the RE. These electrodes are connected electrically to an electrochemical workstation that are basically laboratory equipments or portable in-field devices embedded with inbuilt power source for providing excitation signals to the electrode setup and measurement units for receiving and measuring the response signals. The electrochemical workstation is connected to a computer installed with required software platforms to interpret and analyze the data received from the experiment. For the solutions with small solution resistance, a two electrode cell setup having WE and RE is employed to measure the electrode potential. The two electrode cell setup is depicted in Fig. 3(a). However, for electrochemical experiments having larger solution resistance involving nonaqueous solutions with low conductivities, a three electrode cell setup having WE, RE and CE is used as depicted in Fig. 3(b).

2. Electrochemical sensing of heavy metal ions Electrochemical sensing of HMI involves the use of biosensing electrodes that are employed for the purpose of passing current to the aqueous solution and generate some useful and measurable electrical signal in correspond to the electrochemical reactions within the solution due to presence of metal ions. It is due to the miniaturization of these electrodes and easy electrode modifications, the electrochemical instrumentation setup is generally compact, simple and portable making this technique effective and widely useful for HMI detection (Kudr et al., 2015; Nejdi et al., 2014, 2013; Locatelli and Melucci, 2013). These electrochemical techniques usually employ a setup having three electrodes, working electrode (WE), count electrode (CE) and reference electrode (RE) (Fig. 1) (Cui et al., 2015). The WE can be modified with different materials for specific determination of heavy metal ions (Bontidean et al., 1998; Pan et al., 2009). These interface

4. Various electrochemical techniques for HMI Detection Electrochemical techniques for detection of heavy metal ions in an aqueous solution are classified according to the different electrical signals generated in the solution due to the presence of HMI. The presence of HMI can cause change in various electrical parameters like current, voltage, electrochemical impedance, charge and electroluminescence (Cui et al., 2015; Combellas et al., 2008; Fan et al., 2009). Based on various electrical signals, electrochemical techniques are classified into Amperometric, voltammetric, potentiometric, impedance measurement, coulometric and electrochemiluminescent techniques. In most of these techniques, either one of the current or potential is controlled to measure the change in the other parameter.

Fig. 1. General concept for performing electrochemical experiment.

444

Biosensors and Bioelectronics 94 (2017) 443–455

B. Bansod et al.

Fig. 2. General setup for electrochemical detection of HMI.

change in double layer capacitance, solution resistance and charge transfer resistance due to the presence of heavy metal ions. Electrochemiluminescence is another most widely used technique for measuring the HMI concentration in response to the luminescence effect generated while the experiment is performed. These techniques are based on different measurement signals used for determining the analyte (HMI) concentration and their type in the electrolytic solution and involve the use of various electroanalytical instruments. Some of the most used electroanalytical instruments include high input impedance potentiometers, potentiostats, galvanostats and impedance measuring devices. A detailed classification of electrochemical techniques for detection of heavy metal ions is depicted in Fig. 4. Various electrochemical techniques with latest trends of research in these techniques are described below: 4.1. Static techniques: potentiometry Potentiometric methods provide highly selective quantitative determination of some heavy metal ions in water. This technique involves the measurement of emf (E) at zero current. This means, no current is applied for such measurements. Potentiometric techniques are mostly applied to perform quantitative analysis of ions in solutions by using selective electrodes. In comparison with other electroanalytical techniques, these measure activity in a solution rather than concentration for qualitative and quantitative analysis. These techniques have been widely used in the detection of heavy metal ions in complex environmental matrices due to its low cost, short response time, high selectivity and broad range of response (Array and Merkoci, 2012). However, there are certain limitations to these techniques in terms of its high detection limits, reduced sensitivity and difficulties in electrode miniaturization. In this context, nanomaterials application as the interface material for working electrodes in combination with these techniques is a promising area of research with carbon nanotubes and metal nano-particles as mostly employed categories (Düzgün et al., 2011; Bakker and Pretsch, 2008). These potentiometric nano-electrodes have been reported with improved sensitivity and achieve lower limits of detection for HMIs in various environmental matrices. There are two main categories of devices that are employed in potentiometric

Fig. 3. (a) Two electrode cell setup (b)Three electrode cell setup (Bard and Faulkner, 1944).

Both the parameters, i.e. current and potential cannot be controlled simultaneously making the basis for potentiostatic or galvanostatic measurement techniques (Harvey, ). Also, there are other techniques where no control signal is provided, i.e. current is zero, while potential across the electrodes. Potential is measured for determining the type of HMI, such techniques are called potentiometric techniques. Other than these, there are impedance measurement techniques on the basis of

445

Biosensors and Bioelectronics 94 (2017) 443–455

B. Bansod et al.

Fig. 4. Classification tree for various electrochemical methods for HMI detection. Table 1 List of various electrochemical biosensors in relation to potentiometric techniques for HMI detection. Electrochemical Platform

Technique

Analyte (HMI)

LOD

Detection range

[Ref]

PSA Nanoparticles MWCNT Iron-cyclam complex 1,2-di-(o-salicylaldiminophenylthio) ethane Nanoporous Silica GOD immobilized ZNO Nanorods modified electrode MWCNT MWCNT MWCNT-NS MWCNT-NS SWCNT PANI NP-silicon rubber solid contact electrode SGAuNP-CE

ISE ISE Coated wire ISE Solid Contact ISE

Pb2+ Hg2+ Fe3+ Cu2+

1.6×10−7 M 2.5×10–9 M 10 mM to 1.0 μ M

10–6.3–10–1.6 M 1.0×10−4–5.0×10−9 M 9.1×10−6 to 1.0×10−1 M –

(Huang et al., 2014) (Khani et al., 2010) (Gupta et al., 2011) (Brinie et al., 2012)

ISE ISE

Hg2+ Hg2+

7.0×10−8 M 0.5 nM

(Mehran et al., 2009) (Chey et al., 2012)

ISE ISE ISE ISE FET ISE

Pb2+ Pb2+ Pb2+ Cu2+ Hg2+ Ag+

> 10−6 M 3.2×10−10 M > 10−7 M > 10−5 M 10×10−9 M 2×10−8 M

1.0×10−7 to 1.0×10−1 mol dm−3 0.5×10−6–0.5×10−4 mM & 0.5×10−4 – 20 mM 1.58×10-6–10−3 M 5.9×10−10–1.0×10−2 M 10−7–10−2 mol L−1 10−6–10−1 mol L−1 10 nM – 1 mM 10−7–10-4 M

ISE

Al3+

2.0×10−10 M

5.0×10−10– 5.0×10−2 M

SGAuNP-CE

ISE

3+

Al

SiNWs PVC based membrane

FET AlGaN/GaN Transistor

Cu2+ Hg2+

(Mashhadizadeh and Khani, 2010) (Mashhadizadeh and Talemi, 2011) (Bi et al., 2008) (Zhou and Wei, 2008)

and Cu

2+

−7

1.6×10 and 4.0×10−7 M 1×10−9 M 10–7 M

−7

−2

−1

4.3×10 –1.0×10 mol L for Cu and 4.5×10−7–1.6×10−3 mol L−1 for Al – –

(Parra et al., 2011) (Guo et al., 2011) (Ganjali et al., 2010) (Ganjali et al., 2011) (Kim et al., 2009) (Lindfors et al., 2010)

PSA: polysulfoaminoantraquinone; ISE: ion selective electrodes; MWCNT: multi-walled carbon nanotubes; GOD: glucose oxidase; ZNO: Zinc Oxide; MWCNT-NS: multi-walled carbon nanotubes - nanosilica; SWCNT: single wall carbon nanotubes; FET: field effect transistors; PANI NP: polyaniline nanoparticles; SGAuNP-CE: sol-gel gold nanoparticles based carbon electrode; SiNWs: silica nanowires, PVC: Polyvinyl Chloride.

uses carbon paste electrode for potentiometric detection of Hg2+ ions coupled with MWCNT (Khani et al., 2010). A detection limit of 2.5×10–9 M have been reported for Hg2+ ions with a short response time (ca. 5 s) along with the advantages of long term usage of upto 55 days. Some researchers report the usage of organic polymers coupled with potentiometric sensors for detection of HMIs. Gupta et al. (2011) Reported a coated-wire ISE based on iron-cyclam complex for determination of Fe3+ by ion selective potentiometery. The linear range for detection of Fe3+ ions was found to be10mM to 1.0 μ M. Another research uses solid-contact ISE using 1,2-di-(o-salicylaldiminophenylthio) ethane as neutral carrier to mix with carbon link for Cu2+ ions detection with a wide linear range (Brinie et al., 2012). The introduction of nanostructured material as transducer in ISEs has led to the development of new types of potentiometric sensors (Cui et al., 2015). Some works describe the use of silica based nanostructures in the development of ISEs for simplicity of design, easy fictionalization,

techniques: Ion -selective electrodes (IESs) and field-effect transistors (FETs).Table 1 represents research related to heavy metal ion detection using various potentiometric techniques (Gumpu et al., 2015; Array and Merkoci, 2012). ISEs include a selective polymeric membrane to reduce the matrix interferences. This is an interesting area of analytical research due to their accuracy, quick response, non-destructive and low cost of analysis (Radu and Diamond, 2007). The use of carbon nanostructured materials as transducers in ISEs have replaced this polymeric membrane by receptors directly linked to the transducer surface owing to its excellent physiochemical properties. ISEs were developed by using electrically conducting polysulfoaminoantraquinone (PSA) nanoparticles as solid ionospheres in the sensing membrane for detecting Pb2+ ions with the detection limits of 1.6×10−7M and showed stability for 21 days (Huang et al., 2014). An increase in potential was reported for increased concentration of Pb2+ ions in the solution. Another research 446

Biosensors and Bioelectronics 94 (2017) 443–455

B. Bansod et al.

reduction at the electrode surface leads to the flow of very large current which is proportional to the concentration gradient at the electrode surface. The current is recorded as a function of time and such experiments are called Amperometric techniques. This technique detects one selected component only from an electrochemically reducible species due to fixed potential of the working electrode. The analyte to be detected undergoes a faradaic reaction at some desired polarity and magnitude of the potential applied. However, due to less surface area of the working electrode, this faradaic reaction is incomplete and only a fraction of analyte reacts. Arduini et al. (2011) uses a nano-CB screen printed electrode to determine mercury ions with a detection limit of 5 nM. Amperometric titrations are carried out by measuring the current produced by titration reactions for many reactions where potentiometery cannot be applied like acid-base titrations. Amperometric biosensors are recent techniques that used biologically modified electrodes to provide qualitative and quantitative information in a complex matrix. Mohammadi et al. (2005) An amperometric biosensor is utilized to detect Hg2+ ions using Invertase, mutarotase and glucose oxidase with 1 nM limit of detection. Chronoamperometery(CA) is a type of amperometric technique that involves the application of a potential step and measuring the resulting current of the working electrode as a function of time. CA has a shorter time scale (milliseconds and seconds) as compared to other amperometric techniques. This technique requires complex and expensive specialized equipment and specialized personnel to handle these equipments. These are also time and labor consuming techniques. However, it provides highly accurate results. Yasri et al. (2011) applies CA using PEDOT: PSS coated graphite carbon electrode for ultrasensitive detection of Pb2+ ions in vegetables with a detection limit of 0.19 nM. This method was presented to be highly sensitive and precise with negligible interference from other metal ions.

robustness and high surface area. This includes the use of nanoporous silica materials and heavy metals selective ionospheres (Mehran et al., 2009) as represented in Table 1. A highly specific potentiometric sensor for Hg2+ was developed by immobilizing glucose oxidase (GOD) on ZNO nanorods modified electrode with a wide linear range and detection limits of 0.5 nM (Chey et al., 2012). However, these enzyme based ion-selective sensors are difficult to fabricate and possess poor stability and reproducibility that limits their application. A general field effect transistor (FET) measures the flow of current across a transistor that links the source and drain. This current is controlled by external electric field applied across the FET drain and source. Ion selective field effect transistors (ISFETs) are special category of potentiometric chemical sensors that transduces information from chemical to electrical domain. ISFET biosensors are currently used in variety of applications for biological and environmental analysis owing to its unique electrical and chemical properties. Modern ISFET biosensors are suitable for miniaturized measurement systems, thereby allowing its integration into the required electronics (Asadnia et al., 2016). This device can be fabricated in compact size and light weight that is appropriate for portable hand-held and in-field monitoring devices. Recently, various types of biological materials like DNA, enzymes, proteins and cells are being applied to ISFET for improving its sensitivity and selectivity. Some nano-FETs have been applied for the detection of heavy metal ions achieving very low detection limits (Zhou and Wei, 2008). Kim et al. (2009) have used SWCNT to construct FETs to detect Hg2+ ions from buffer solution with the detection limits of 10×10−9 M. Also, SiNWs based FETs have been employed for the detection of Cu2+ ions in the buffer solution with the limit of detection upto 1×10−9 M. 4.2. Potentiostatic techniques

4.2.2. Chronocoulometry Chronocoulometric (CC) techniques are the integral analogs of Amperometric techniques. These techniques involve the measurement of amount of charge passed after providing a controlled potential that is calculated by taking integral of current vs time or voltage. These techniques are mostly applied to perform exhaustive electrolysis for quantitative analysis while providing very less information on type of the analyte. CC techniques are mostly applied for electroactive materials to determine the extent of adsorption of species which undergoes reaction at the electrode surface. This electrolysis is carried out at constant current as compared to constant potential in other amperometric and voltammetric techniques. In contrast to amperometric techniques, chronocoulometry involves the use of larger surface area electrodes leading to higher efficiency due to approximately 100% reaction of the analyte. Although this technique provides the advantages of high precision and simplicity but needs a high current efficiency due to which it is not widely used for performing electrochemical analysis. Choi et al. (2015) Graphene oxide doped DTT electrode was used to detect Cd2+, Pb2+, Cu2+ and Hg2 using CC stripping technique with the detection limits of 1.9 ± 0.4 ng mL−1, 2.8 ± 0.6 ng mL−1, 0.8 ± 0.2 ng mL−1, 2.6 ± 0.9 ng mL−1 and CC deposition method with the detection limits of 2.6 ± 0.2 ng mL−1, 0.5 ± 0.1 ng mL−1, 1.8 ± 0.3 ng mL−1, 3.2 ± 0.3 ng mL−1.

Potentiostatic techniques involve the use of a potentiostat instrument to control the potential between its reference electrode and counter electrode to maintain a potential difference between the reference and working electrode as depicted in Fig. 5. The resulting current is measured and recorded accordingly to predict the analytes concentration. Such experiments are also called controlled potential techniques. These controlled potential techniques are further divided into various categories according to the type of voltage signal applied and resultant measured current waveforms. Three basic subcategories of potentiostatic techniques are: Amperometry, Chronocoulometry and Voltammetry/Polarography. Most of the work done using these techniques for HMI detection is illustrated in Table 2. 4.2.1. Amperometry Amperometry is part of controlled potential techniques in which very small currents are controlled and measured at a fixed potential using a non-mercury working electrode. This technique usually uses a potential step signal to be provided between the reference and working electrode in the solution containing electroactive species. Resultant

4.2.3. Voltammetry and Polarography Voltammetric techniques are most widely used in the determination and measurement of heavy metal ions in various complex environmental matrices. These techniques employ measuring current at various potential points in a current - voltage curve in contrast to the fixed potential point in amperometric technique. Voltammetry is widely used technique for trace metal speciation due to its high accuracy and sensitivity. These techniques are suited to partially suppress the background current and improve the limit of detection. Qualitative information can be obtained by studying the reversibility of

Fig. 5. General potentiostatic measurement experimental setup.

447

SWASV SWAdSV SWASV

SWASV CV SWASV

SWASV and CV SI-ASV SWASV

CC Stripping method CC deposition method SWASV ASV CV ASV

Bi-C nanocomposite

Si NWs-SH/GCE Sucrose biosensor using UME Chemically modified CPE

Gr and the OPFP IL modified CPE BDD-TFE N/IL/G/SPCE

GO/DTT

448

1 ng mL−1 –10 μg mL−1 1 ng mL−1 –10 μg mL−1 1 ng mL−1 –2.5 μg mL−1 0.5 μg L−1 –30 μg L−1 1 nM –5 μM For Cd2+: 50–250 µg L−1 , For Pb2+: 5– 200 µg L−1 0.2–2.8 M, 0.0025–0.0225 M, 0.2–2.8 M, and 0.02 −0.6 M 0.1–1.0 M for Cd2+, Pb2+ and Cu2+and 0.8–2.0 M for Hg2+ 0.1–10 μM

3.57×10-10 mol L-1, 4.50 ×10-10 mol L-1 and 3.86 ×10-10 mol L-1 0.04 ng m L−1 0.09 ng m L−1, 0.06 ng m L−1 and 0.08 ng m L−1 1.9 ± 0.4 ng m L-1, 2.8 ± 0.6 ng m L-1, 0.8 ± 0.2 ng m L-1, 2.6 ± 0.9 ng m L-1 2.6 ± 0.2 ng m L-1, 0.5 ± 0.1 ng m L-1, 1.8 ± 0.3 ng m L-1, 3.2 ± 0.3 ng m L-1 7.1 ± 0.9 ng m L-1, 1.9 ± 0.3 ng m L-1, 0.4 ± 0.1 ng m L-1, 0.7 ± 0.1 ng m L-1 0.2 μ g L-1 and 0.1 μ g L-1 0.094 nM 3.2μ g L-1 and 1.9 μ g L-1

Cd2+, Pb2+, Cu2+ and Hg2+

Pb2+ and Cd2+ Hg2+ Cd2+ and Pb2+

60 nM 0.1 nM 25 nM

Zn2+ and Pb2+ Cu2+ Sb2+ Zn2+, Cd2+ and Pb2+ Cd2+ Cd2+ Zn2+ Cd2+, Pb2+, Ni2+ and Hg2+ Pb2+ Cd2+, Pb2+, Ni2+ and Hg2+ Pb2+ Hg2+ 2+

SWASV

DPASV DPCSV SCP AGNES-SCP SSCP SWASV LSASV SWASV

SWASV DPASV

SWASV

EIS

3MT and 3TA CPE

HMDE

HgFE HMDE Hg Film SPE Hg Film SPE Graphite Felt B-doped DLC

BDD BDD

0.19 nM 0.48 μ M 10-20 M

Cd2+

CA DPASV

Conductometry

GC/PEDOT: PSS Au/MPS-(PDDA-AuNPs)

Alkaline phosphatase

–

(Pereira et al., 2011)

10-8–10-6, 2.5x10-8 – 2.5x10-7, 5x10-8 – 5x10-6 & 10-7 –10-5 respectively 2 nmol L−1–0.1 μmol L−1 20–100 μM 0.5 nM, 5 nM, 100 nM and 500 nM

Pb2+, Cu2+, Hg2+ and Cd2+ Pb2+ As3+

SWASV

(Nasraoui et al., 2010)

–

Pb

(Rouis et al., 2013)

–

LSASV

(Tonle et al., 2011)

Thiol functionalized clay modified CPE β -ketoimine calix (Afkhami et al., 2013a)arene on ITO TETRAM-modified graphite felt electrode Complexing polymer films

20 ppb –100 ppb Upto 35 nM, 48 nM, 97 nM & 5 nM respectively 3 x10-7–10-5 M

19.3 nM 3.29 nM, 26.5 nM, 116 nM and 11.5 nM

(Yasri et al., 2011) (Ottakam Thotiyl et al., 2012) (Tekaya et al., 2013) (continued on next page)

(Le et al., 2012) (Sbartai et al., 2012)

(Tanguy et al., 2010) (Parat et al., 2011a) (Parat et al., 2011b) (Zaouak et al., 2010) (Feier et al., 2012) (Khadro et al., 2011)

12.4–23.2 nM for Zn, 1.7–3.2 nM for Pb 4.9–7.6 nM for Cu – 25–100 nmol L−1 – 0.2–20 μg L−1 10−6–10−4 M 2 –25 μg/L

(Magnier et al., 2011)

(Lin et al., 2009)

(Xu et al., 2013)

(Wei et al., 2012a)

(Huang et al., 2014) (Jia et al., 2016) (Rosolina et al., 2015)

(Choi et al., 2015)

(Bagheri et al., 2015) (Chaiyo et al., 2014) (Chaiyo et al., 2016)

(Guo et al., 2016b) (Kestwal et al., 2008) (Afkhami et al., 2013c)

(Zhang et al., 2016)

(Niu et al., 2015)

(Arduini et al., 2011) (Tesarova et al., 2009) (Liu et al., 2015)

[Ref]

2.91 nM and 0.03 nM 0.6 nM 70 pM 4 nM, 2.9 nM and 4.1 nM 2.2 nM 1.78 nM 50 nM 4.83 nM, 8.9 nM, 34.1 nM and 4.99 nM

0.1–10 μ M

SWASV

0.186 nM, 0.247 nM, 0.169 nM and 0.375 nM

0.314, 0.0272, 0.2263, and 0.1439 nM

5 −250 nM 5x10-10–12.5x10-10 M Cd2+: 1.5–1000 ng m L-10.6– 1100 ng m L-1 1.25×10-9–2.00×10-7 mol L-1 0.1–30.0 ng mL−1 and 5.0 – 60.0 ng mL−1 0.1 to 100.0 ng L−1

0.04 mA/nM and 0.074uA/nM 5 x 10-10 M 0.3,0.1 and 0.05 ng m L−1

Zn2+,Cd2+, Cu2+ and Hg2+ Cd2+, Pb2+, Cu2+ and Hg2+ Cu2+

For Cd and Pb: 1–100 ppb Ni: 10–150 ppb 0.1–1.0 μM

0.65 μ g L-1and 0.81 μ g L-1 5.47 μ g L-1 0.1 μM

Pb2+ and Cd2+ Ni2+ Cd2+, Pb2+ and Cu2+ Cd2+ and Pb2+ Hg2+ Cd2+, Cu2+ and Hg2+ Ti+, Pb2+ and Hg2+ Hg2+ Zn2+, Cd2+and Pb2+

0.05–14.77 ppm 4.0–150.0 μg L−1 1–100 nmol L−1

Detection range

5 nM 0.8 μ g L-1and 0.2 μ g L-1 0.15 nM

LOD

Hg Cd2+ and Pb2+ Hg2+

2+

Analyte (HMI)

MgSiO modified GCEs

3

NH3- pn-MWCNTs

GO-MWCNT Y-DNA GCE

SWASV

Amperometry SWASV EIS

NanoCB SPE SbF-CPE Cu2O@ NCs

AuNPs/CNFs

Technique

Electrochemical Platform

Table 2 List of various electrochemical techniques for HMI detection.

B. Bansod et al.

Biosensors and Bioelectronics 94 (2017) 443–455

Conductometry Amperometry

SWASV

SWASV

SWASV

DPV

SWASV DPV DPV

ASV

SWASV

SWASV SWASV

Invertase, mutarotase, glucose oxidase Invertase, mutarotase, glucose oxidase

MWCNT tower based GCE

Carbon NPs SPE

Graphene NS

AuNPs amplified DNA - Gold electrode Cucumber like HAP Nanoarray membrane Nanostructured MIP

RGO/Bi nanocomposite

Porous MGO nano-flowers

AuNP-CNT SnO2/RGO nanocomposite

DPV and DSV Amperometry ECL SWASV CV EIS GSCP

SIA-ASV

SWASV SWASV

DSP-AuNPs MB tag DNA linked luminol AuNPs CdS QDs modified ssDNA HRP-PANI PET-SPE D-LMF based carbon electrode

SPCNTE

BiNPs Nano-Bi

C3N4 modified GCE

Technique

Electrochemical Platform

Table 2 (continued)

0.00423 nM and 0.027 nM 0.4 μ M 0.6 nM

Pb2+ and Cd2+ Cu2+ Pb2+ Cd2+, Pb2+, Zn2+ and Cu2+ Pb2+ and Cd2+

0.2 μg L−1, 0.8 μg L−1 and 11 μgL−1 2 μg L−1and 5 μg L−1 4.20 μg L−1, 2.54 μg L−1and 1.97 μg L−1

Pb2+ and Cd2+ Zn2+, Cd2+ and Pb2+

0.48 nM 0.2 nM 1.05 x 10-10 M 7.8 pM 0.5 nM 1 nM and 1 nM 0.02 μ g L-1, 0.02 μ g L-1 and 0.06 μ g L-1

0.09 nM

1×10−9 M–1×10−10 M and 1×10−6 M – 1×10−9 M 1.0–1000 nM 0–80 nM 2 to 1000 pM 0.01 nM to 1.0 μM 1.0×10-5 ng/mL to 10.0 ng/mL 50 μM - 1 mM & 0–50 μM respectively 0.07 and 0.42, 0.06 −0.36, and 2.0– 6.0 µg L-1 respectively 2–100 μg L−1 for Pb2+ & Cd2+and 12– 100 μg L−1 for Zn2+ – –

3.3 −22 nM for Pb(II) & 40 −140 nM for Cd(II) 3.31 ppb –22.29 ppb 0 to 1.3 μM

2.1 pM and 81 pM

449

(Cadevall et al., 2015) (Lee et al., 2010)

(Sadhukhan and Barman, 2013) (Cui et al., 2014) (Xuan et al., 2013) (Gao et al., 2013) (Tang et al., 2013) (Li et al., 2013) (Avuthu et al., 2014) (Szłyk and Czerniak, 2004) (Injang et al., 2010)

(Bui et al., 2012) (Wei et al., 2012c)

(Wei et al., 2012b)

20–120 mg L−1

2.8 μ g L-1, 0.55 μ g L-1, 17 μ g L-1 and 26 μ g L-1

0.546 μ g L-1 and 0.613 μ g L-1 0.1 nM, 0.18 nM, 0.23 nM and 0.28 nM

(Zhang et al., 2011) (Zhuo et al., 2010) (Alizadeh and Amjadi, 2011) (Sahoo et al., 2013)

(Kong et al., 2009)

(Wang et al., 2011)

0.01–10 nM for Pb2+ and Cd2+ 1.3–35.2 μM & 35.2–98 μM 1.0 × 10−9 to 8.1 × 10−7 M

-8

M, 10 M and 10 M

-7

Cu2+ Hg2+ Hg2+ Pb2+ Pb2+ Pb2+ and Cd2+ Cd2+, Pb2+ and Cu2+ Pb2+, Cd2+ and Zn2+

Pb2+ and Cu2+ Cd2+, Pb2+, Cu2+ and Hg2+ Hg2+

1–100 nM

0.5 nM

10

-11

12 nM, 25 nM, 44 nM and 67 nM

(Aragay et al., 2011b)

(Soldatkin et al., 2012) (Mohammadi et al., 2005) (Guo et al., 2011)

0.1 –100 μM –

4.8 nM, 4.4 nM, 7.9 nM and 5 nM

[Ref]

Detection range

2–8 μM for Cu2+, Pb2+, Cd2+and 4.2 μM – 16.8 μM for Zn2+ 5–100 μg L−1 for Cd2+, Pb2+ and Cu2+1 – 10 μg L−1 for Hg2+ –

25 nM 10 nM

LOD

Pb2+, Cd2+, Cu2+ and Zn2+ Pb2+, Cd2+, Cu2+ and Hg2+ Pb2+, Cd2+ and Cu2+ Hg2+

Hg Hg2+

2+

Analyte (HMI)

B. Bansod et al.

Biosensors and Bioelectronics 94 (2017) 443–455

Biosensors and Bioelectronics 94 (2017) 443–455

B. Bansod et al.

electrodes offer a well-defined, undistorted, and highly reproducible stripping response, excellent resolution of neighbouring peaks, high hydrogen evolution, wide linear dynamic range, with signal-to-background characteristics comparable to those of common mercury electrodes (Wang et al., 2000). Electroplating techniques are applied onto electrode surfaces such as glassy carbon electrodes (Kefala et al., 2003), boron doped diamond electrodes (BDD) (Toghill et al., 2009),gold microelectrodes (Zou et al., 2008) and screen-printed electrodes (SPE) (Lezi et al., 2012) to generate bismuth films. Bismuth nanoparticles (BiNPs) used as electrode modifiers have proven to be highly accurate and reliable for trace level detection of HMI in concurrence with ASV technique (Rico et al., 2009). BDD has electrochemical properties very similar to those of Hg, and has been found to yield good detection limits for several HMI. However, the lower background current and wider anodic potential limit its advantages over Hg (Show et al., 2003; Granger et al., 2000).

reactions in the electrochemical cell setup. It is highly suitable technique for turbid and colored solutions that are otherwise difficult to analyze with other electroanalytical techniques. The use of conventional electrodes for performing these experiments with a linear sweep of potential (10 mV/s to about 1000 mV/s) to measure the resulting i-E curve is called linear sweep voltammetry (LSV). These experiments involving a double potential step by reversing the potential scan leads to current reversal and often called as cyclic voltammetry (CV). Voltammetric experiments when performed with potential step on dropping mercury electrode (DME) are referred to as Polarography or simply DC polarography. For concentrations higher than 10−5 M, LSV on Dropping mercury electrode (DME) or static mercury drop electrode (SMDE) generated at the end of glass capillary is well-suited (Pujol et al., 2014). The concept of using a pulse of voltage signal having different shapes and amplitudes in voltammetric measurement is referred to as pulse voltammetry that is further subcategorized into: Normal pulse voltammetry (NPV) or Normal pulse polarography (NPP), Staircase voltammetry or Tast polarography, Reverse pulse voltammetry or polarography (RPV), Differential pulse voltammetry or polarography (DPV) and Square wave voltammetry (SWV). These techniques are suited to partially suppress the background current and improve the limit of detection. Out of various pulse voltammetric methods, differential pulse and square wave voltammetry are most commonly used due to their high sensitivity suitable for trace level analysis. The stripping voltammetry is further characterized into anodic stripping voltammetry (ASV) or cathodic stripping voltammetry (CSV)by applying and anodic potential scan or a cathodic potential scan respectively. ASV is a commonly used electrochemical technique for quantitative analysis of electroactive species such as metals ions. Very low detection limits of upto picomolar range have been achieved with this technique (Kissinger and Heineman, 1996; Krolicka et al., 2003). In addition to a very low limit of detection, stripping voltammetry requires relatively simple and inexpensive instrumentation, with exceptional suitability for miniaturization (Jothimuthu et al., 2011). These ASV and CSV methods have been used in combination with various pulse voltammetric techniques on hanging mercury drop electrode (HDME) for trace level detection of metal ions. The resulting methods, linear sweep anodic stripping voltammetry (LSASV), differential pulse anodic stripping voltammetry (DPASV), square wave anodic stripping voltammetry (SWASV) and their combinations allow limits of detection as low as 10−12 M. Differential alternative pulse voltammetry (DAPV) is another modified voltammetric technique that is based on the superimposition on the main electrode potential of a pair of single successive rectangular pulses characterized by small, equal amplitudes and durations (from1to100ms) but opposite polarities. This technique offers the advantages of high resolution power and simplicity in the involved instrumentation. Mercury electrodes have been traditionally used for ASV or potentiometric stripping analysis (Tarley et al., 2009)to obtain high sensitivity, reproducibility, and a wide cathodic potential range. High toxicity of mercury and its problems associated with handling these electrodes restricts its use as an electrode material. Several alternative electrodes have been investigated, including Ir (Nolan and Kounavis, 1999; Herdan et al., 1998), Au (Andrews and Johnson, 1975; Wang and Tian, 1993; Viltchinskaia et al., 1995; Bonfil et al., 1999; Feeney and Kounaves, 2000) and Ag (Kirowa-Eisner et al., 1999; Bonfil and Kirowa-Eisner, 2002). All of these electrodes have their limitations and they do not perform as well as Hg on an average. Another electrode that has shown promising results for ASV is a Bi-modified electrode (Wang et al., 2000; Wang et al., 2001a; Wang et al., 2001b; Flechsig et al., 2002; Pauliukaite et al., 2004). Bismuth has emerged as a promising electrode material in the field of electroanalysis that is mostly applied in electrochemical stripping, voltammetric and amperometric-based sensors (Wang, 2005; Anık et al., 2008; Anık and Timur, 2007; S vancara et al., 2010; Mayorga-Martinez et al., 2013) due to its eco- friendly characteristics as compared to mercury. As it is well reported, bismuth

4.3. Galvanostatic techniques Galvanostatic techniques involve the use of current source (galvanostat) in order to control the current between the working electrode and counter electrode and resulting potential is measured across the working and reference electrodes. Such experiments are characterized under chronopotentiometric or galvanostatic techniques. A general experimental setup for these techniques is represented in Fig. 6. Compared to the potentiostatic techniques, galvanostatic technique employ a simple instrumentation as no feedback from the reference electrode is required in this technique. However, these techniques suffer from the disadvantages of large double layer charging effects occurring throughout the experiment. It could also be further characterized into current reversal chronopotentiometry and cyclic chronopotentiometry. Another mostly applied technique for heavy metal ion detection is galvanostatic stripping chronopotentiometry (SCP). SCP constitutes a valuable substitute to ASV as it has been empirically proved to be less sensitive to the presence of important quantities of organic matter (Estela et al., 1995; Jagner, 1982; Gozzo et al., 1999). Due to these advantages, SCP has been extensively used for detection of heavy metal ions in food, beverages and biological samples (Serrano et al., 2003). The use of constant current stripping chronopotentiometry in a handing mercury drop electrode (HMDE) has been reported in (Town and van Leeuwen, 2001, 2002) for heavy metal speciation. A galvanostatic stripping chronopotentiometric (GSCP) method for the simultaneous determination of cadmium, lead, and copper in commercial margarines and butters is described by (Szłyk and Czerniak Szydłowska, 2004). Some other works related to SCP applications in trace level detection of heavy metal ions have also been reported in Table 2. nano CB: nano carbon black, SPE: screen-printed electrodes, SbF: antimony film, CPE: carbon paste electrode, Cu2O@NCs: cuprous oxide and nano chitosan composites, Bi-C: bismuth-carbon, AuNPs/CNFs: gold nanoparticle on carbon nanofibers, SiNWs-SH: thiol-silicon nanowires, GCE: glassy carbon electrode, UME: ultra-microelectrode, Gr: graphene, OPFP-IL: 1-noctylpyridinum hexafluorophosphate,

Fig. 6. General Galvanostatic measurement experimental setup.

450

Biosensors and Bioelectronics 94 (2017) 443–455

B. Bansod et al.

BDD: boron doped diamond, TFE: Thin film electrode, N/IL/G/SPCE: Nafion/ionic liquid/graphene composite modified screen-printed carbon electrode, GO: graphene oxide, DTT: doped diaminoterthiophene, MWCNT: multi-walled carbon nanotubes, Y-DNA: Y-shaped DNA, NH3-pn: NH3-plasma treated, MgSiO3: magnesium silicate hollow spheres, 3MT: 3-methyl thiophene, 3TA: 3-thiophene acetic acid, HMDE: hanging mercury drop electrode, HgFE: mercury film electrode, DLC: diamond like carbon, ITO: indium tin oxide, TETRAM: 1,4,8-tri(carbamoylmethyl) hydroiodide, GC: graphite electrode coated, PEDOT: 3,4-poly(ethylenedioxythiophene), PSS: poly(styrene sul-fonate), Au/MPS-(PDDA-AuNPs): Multilayers of poly(diallyldimethylammonium chloride) and citrate capped Au nanoparticles, NS: nanosheets, HAP: hydroxyapatite, MIP: molecular imprinted polymer, RGO/Bi: reduced graphene oxide bismuth nanoparticles, MgO: manganese oxide, CNT: carbon nanotubes, SnO2: tin oxide, C3N4: graphiticcarbon nitride, DSP-AuNPs: dithiobis(succinimidyl-propionate) encapsulated AuNPs, MB tag: methylene blue labeled T rich probe, GR5 DNAzyme: lead dependent DNAzyme, QDs: Quantum dots, HRP: horseradish peroxidase, PANI: polyaniline, PET: polyethylene terephthalate, D-LMF: latent mercury film type electrode, SPCNTE: screen printed carbon nanotube electrode, BiNPs: bismuth nanoparticles, Nano-Bi: bismuth nanopowder electrodes, SWASV: square wave anodic stripping voltammetry, EIS: electrochemical impedance spectroscopy, SWAdSV: Square wave adsorptive stripping voltammetry, CV: Cyclic voltammetry, SI-ASV: sequential injection anodic stripping voltammetry, CC: chronocoulometry, ASV: anodic stripping voltammetry, DPASV: differential pulse anodic stripping voltammetry, DPCSV: differential pulse cathodic stripping voltammetry, SCP: stripping chronopotentiometry, SSCP: stripping chronopotentiometry at scanned deposition potential, LSASV: linear sweep anodic stripping voltammetry, CA: chronoamperometery, DPV: differential pulse voltammetry, ECL: electrochemiluminescence, GSCP: galvanostatic stripping chronopotentiometry.

Fig. 7. An idealized Randles electrical equivalent circuit for an electrochemical reaction. Cd, double-layer capacitor; Rp, polarization resistance; Rs, solution resistance; ZW, Warburg impedance.

of 5–15 mV of given frequency is overlaid on a dc bias voltage and resulting ac current is measured. Different impedance values are noted for different voltage and current measurements are made at desired frequencies by scanning the frequency. However, this technique requires long data acquisition time. Avuthu et al. (2014) presents a flexible screen printed three electrode electrochemical sensor on a polyethylene terephthalate (PET) film. This screen printed sensor was able to detect very low concentrations of toxic heavy metal ions. EIS response of this screen printed electrode revealed a very high sensitivity at nano molar (nM) concentration levels of lead nitrate (Pb (NO3)2) and cadmium nitrate (Cd(NO3)2) as reported in Table 2. Impedance measurement technique was also employed by (Liu et al., 2015) for the detection of Hg2+ ions with a detection limit of 0.15 nM using cuprous oxide and nano chitosan composites. Rouis et al. (2013) built an impedancemetric sensor dedicated to the detection of Hg2+ ions by immobilizing a β -ketoimine calix (Afkhami et al., 2013a) arene derivative in a conducting polymer with a detection limit of 0.1 nM. 4.5. Electrochemiluminescence techniques Some of the homogeneous electron transfer reactions occurring in the chemical solutions involving radical ions generate an effect of chemiluminiscence. This chemiluminiscence is often triggered due to electrolytic production of free radicals in chemical reactions thus called electrochemiluminescence (ECL). These techniques are often used to detect a specific metal ion in some solution based on fluorescence detection that is rather highly sensitive (parts per billion/ trillion), simple and inexpensive. Gao et al. (2013) employed the use of modified DNA strands to detect Hg2+ ions. The electrochemical platform applied for detection of Hg2+ ions was DNA linked luminol AuNPs with ECL system that could detect Hg2+ ions within a linear range from 2×10−10 M to 2×10−8 M with a detection limit of 1.05×10−10 M. Quantum dots (QDs) are finding their applications in ECL sensing due to their broad excitation spectra and narrow Gaussian emission providing a wide tuning range from ultraviolet (UV) region to near infra red (NIR) region due to quantum size effect (Gill et al., 2008). First ECL sensor based on CdSe QDs was developed in 2004 (Zou and Ju, 2004). Recently, a low potential ECL method was designed for the detection of Cu2+ ions using CdTe QDs (Cheng et al., 2010). However, the toxicity of QDs has lead to decreased use of QDs for detection of heavy metal ions.

4.4. Impedance measurement techniques Some of the most widely used impedance measurement techniques for determining the analytes concentration in an aqueous solution are electrochemical impedance spectroscopy (EIS) and AC voltammetry. Out of these two techniques, EIS have been employed by various researchers in metal ion speciation from different biological and other environmental samples. EIS technique is widely employed to study the interfacial properties of modified electrodes especially for multilayer films. It was also proved to be an efficient tool for recognition of appropriate interface properties that could be successfully applied in biosensing (Jovanovic et al., 2013). EIS is a well developed branch of ac theory that describes the response of circuit to an alternating current or voltage as a function of frequency (Research, 1987). This technique serves as an inexpensive and simple technique for sensitive detection of toxic metal ions in biological and chemical matrices as compared to other electroanalytical techniques. In EIS, an electrochemical reaction that takes place in an electrolytic cell is represented in terms of an electrical equivalent circuit (EEC). The current flowing in an electrified interface due to an electrochemical reaction leads to charge transfer along the electrified interface that further generates both faradaic and non-faradaic components (Orazem and Tribollet, 2008). An idealized electrical equivalent circuit including these faradaic and non faradaic components for an electrochemical reaction is represented in Fig. 7. The high-frequency components are shown on the left, and the lowfrequency components are shown on the right (Orazem and Tribollet, 2008). By determining this impedance parameter and other resistive – capacitive (RC) parameters of the EEC, one could predict the metal ion concentration in an electrolytic solution. Out of different impedance measurements, frequency response analyzer (FRA) has been proved to be the most widely used technique for determining the analytes concentration. This is a single-sine method in which a small sine wave

5. Conclusion and future scope This review presents general setup required for electrochemical sensing of heavy metal ions and briefly discusses various electrical parameters involved in electrochemical measurements. Also different electrochemical techniques have been characterized on the basis of the electrical measurement signals, i.e. potentiostatic techniques, galvanostatic techniques, static techniques/potentiometery, impedance measurement and electrochemiluminescence. These techniques are further described in terms of their electrochemical behavior along with the operation of measuring instruments applied for the measurements of 451

Biosensors and Bioelectronics 94 (2017) 443–455

B. Bansod et al.

Atashbar, M.Z., 2014. Detection of heavy metals using fully printed three electrode electrochemical sensor. Sens. IEEE 10, 669–672. Bagheri, H., Afkhami, A., Khoshsafar, H., Rezaei, M., Sabounchei, S.J., Sarlakifar, M., 2015. Simultaneous electrochemical sensing of thallium, lead and mercury using a novel ionic liquid/graphene modified electrode. Anal. Chim. Acta 870, 56–66. Bakker, E., Pretsch, E., 2008. Nanoscale potentiometry. Trends Anal. Chem. 27, 612. Barbosa, F., Krug, F.J., Lima, É.C., 1999. On-line coupling of electrochemical preconcentration in tungsten coil electrothermal atomic absorption spectrometry for determination of lead in natural waters. Spectrochim. Acta B 54, 1155–1166. Bard, A.J., Faulkner, L.R., 1944. Electrochem. Method.: Fundam. Appl., 1–39, (2nd ed.). Bernalte, E., Marín Sánchez, C., Pinilla Gil, E., 2011. Determination of mercury in ambient water samples by anodic stripping voltammetry on screen-printed gold electrodes. Anal. Chim. Acta 689, 60–64. Bi, X., Agarwal, A., Balasubramanian, N., Yang, K., 2008. Tripeptide-modified silicon nanowire based field-effect transistors as real-time copper ion sensors. Electrochem. Commun. 10, 1868. Bonfil, Y., Kirowa-Eisner, E., 2002. Determination of nanomolar concentrations of lead and cadmium by anodic-stripping voltammetry at the silver electrode. Anal. Chim. Acta 457, 285–296. Bonfil, Y., Brand, M., Kirowa-Eisner, E., 1999. Determination of sub-μg l−1 concentrations of copper by anodic stripping voltammetry at the gold electrode. Anal. Chim. Acta 387, 85–95. Bontidean, I., Berggren, C., Johansson, G., Csoregi, E., Mattiasson, B., Lloyd, J.A., Jakeman, K.J., Brown, N.L., 1998. Detection of heavy metal ions at femtomolar levels using protein-based biosensors. Anal. Chem. 70, 4162–4169. Brinie, S., Buzuk, M., Generalic, E.J., 2012. Solid-contact Cu(II) Ion-.-Sel. electrode based 1,2-di-(o-Sali.)ethane. Solid State Electrochem. 16, 1333–1341. Bui, M.P.N., Li, C.A., Han, K.N., Pham, X.H., Seong, G.H., 2012. Simultaneous detection of ultra trace lead and copper with gold nanoparticles patterned on carbon nanotube thin film. Analyst 137, 1888–1894. Cadevall, M., Ros, J., Merkoc, A., 2015. Bismuth nanoparticles integration into heavy metal electrochemical stripping sensor. Electrophoresis 36, 1872–1879. Callender, E., 2004. Heavy metals in environment-historical trends. Treatise Geochem. 9, 67–105. Caroli, S., Forte, G., Iamiceli, A.L., Galoppi, B., 1999. Determination of essential and potentially toxic trace elements in honey by inductively coupled plasma- based techniques. Talanta 50, 327–336. Chaiyo, S., Chailapakul, O., Siangproh, W., 2014. Highly sensitive determination of mercury using copper enhancer by diamond electrode coupled with sequential injection–anodic stripping voltammetry. Anal. Chim. Acta, xxx, (xxx–xxx). Chaiyo, S., Mehmeti, E., Žagar, K., Siangproh, W., Chailapakul, O., Kalcher, K., 2016. Electrochemical sensors for the simultaneous determination of zinc, cadmium and lead using a Nafion/ionic liquid/graphene composite modified screen-printed carbon electrode. Anal. Chim. Acta918, 26–34. Cheng, L., Liu, X., Lei, J., Ju, H., 2010. Low-potential electrochemiluminescent sensing based on surface unpassivation of CdTe quantum dots and competition of analyte cation to Stabilizer. Anal. Chem., 82, (3359–33). Chey, C.O., Ibupoto, Z.H., Khun, K., Nur, O., Willander, M., 2012. Indirect determination of mercury ion by inhibition of a glucose biosensor based on ZnO nanorods. Sensors 12, 15063–15077. Choi, S.M., Kim, D.M., Jung, O.S., Shim, Y.B., 2015. A disposable chronocoulometric sensor for heavy metal ions using a diaminoterthiophene-modified electrode doped with graphene oxide. Anal. Chim. Acta xxx, 1–8. Combellas, C., Kanoufi, F., Pinson, J., Podvorica, F.I., 2008. Sterically hindered diazonium salts for the grafting of a monolayer on metals. J. Am. Chem. Soc. 130, 8576–8577. Cui, L., Wu, J., Li, J., Ge, Y., Ju, H., 2014. Electrochemical detection of Cu2+ through Ag nanoparticle assembly regulated by copper-catalyzed oxidation of cysteamine. Biosens. Bioelectron. 55, 272–277. Cui, L., Wu, J., Ju, H., 2015. Electrochemical sensing of heavy metal ions with inorganic, organic and bio-materials. Biosens. Bioelectron. 63, 276–286. Directive, 2013. 2013/35/EU of the European Parliament and of the Council. Düzgün, A., Zelada-Guillén, G.A., Crespo, G.A., Macho, S., Riu, J., Rius, F.X., 2011. Nanostructured materials in potentiometry. Anal. Bioanal. Chem. 399, 171–181. Estela, J.M., Tomas, C., Cladera, A., Cerda, V., 1995. Potentiometric Stripping Analysis: a Review. Crit. Rev. Anal. Chem. 25, 91. Fan, L., Chen, J., Zhu, S., Wang, M., Xu, G., 2009. Determination of Cd2+ and Pb2+ on glassy carbon electrode modified by electrochemical reduction of aromatic diazonium salts. Electrochem Commun. 11, 1823–1825. Feeney, R., Kounaves, S.P., 2000. On-site analysis of arsenic in groundwater using a microfabricated gold ultramicroelectrode array. Anal. Chem. 72, 2222–2228. Feier, B., Floner, D., Cristea, C., Bodoki, E., Sandulescu, R., Geneste, F., 2012. Flow electrochemical analyses of zinc by stripping voltammetry on graphite felt electrode. Talanta 98, 152–156. Feldmann, J., Salaun, P., Lombi, E., 2009. Critical review perspective: elemental speciation analysis methods in environmental chemistry – moving towards methodological integration. Environ. Chem. 6, 275–289. Flechsig, G.-U., Korbout, O., Hocevar, S.B., Thongngamdee, S., Ogorevc, B., Grundler, P., Wang, J., 2002. Electrically heated bismuth-film electrode for voltammetric stripping measurements of trace metals. Electroanalysis 14, 192–196. Ganjali, M.R., Motakef-Kazami, N., Faridbod, F., Khoee, S., Norouzi, P., 2010. Determination of Pb 2+ ions by a modified carbon paste electrode based on multiwalled carbon nanotubes (MWCNTs) and nanosilica. J. Hazard. Mater. 173, 415. Ganjali, M.R., Aghabalazadeh, S., Khoobi, M., Ramazani, A., Foroumadi, A., Shafiee, A., Norouzi, P., 2011. Nanocomposite based carbon paste electrode for selective Analysis of Copper. Int. J. Electrochem. Sci. 6, 52.

varies electrical signals corresponding the analyte concentration. Among various electrochemical techniques, potentiometric (ISE and FET), voltammetric (SWASV, DPASV, DPCSV, CV, SIA-ASV) and galvanostatic (SCP, GSCP) techniques have been employed mostly for selective determination of HMI with high sensitivity and low detection limits. EIS and ECL techniques have also been reported in some researches for HMI detection. Various interface materials including carbon based materials, polymers, metal oxides, nanomaterials and biomaterials like DNA, enzymes, etc. have been extensively explored as modifiers of conventional electrodes(glassy carbon, graphite, screen printed, mercury film, hanging mercury drop electrodes, etc.) and reported in this review. These electrochemical platforms have been applied along with various electrochemical techniques for HMI detection with enhanced sensitivity and selectivity, wide dynamic range and reduced limits of detection. However, still miniaturization of these electrochemical sensors and equipments involved and simplicity in the design and procedure of electrochemical measurements for HMI detection is a challenging issue. To make these systems suitable for environmental as well as biological monitoring, compact and in-field devices need to be fabricated suitable for in-situ operations and online monitoring. Most of these electrochemical techniques suffer from problems of poor reproducibility and stability and not suited for application in complex matrices and real samples. Also, toxicity of some interface materials like mercury, QDs requires a great consideration prior to their application for HMI detection in real water samples and other environmental matrices. Acknowledgements Authors would like to acknowledge the Central Scientific Instruments Organization, Chandigarh for this project. References Afkhami, A., Felehgari, F.S., Madrakian, T., Ghaedi, H., Rezaiwala, M., 2013a. Fabrication and application of a new modified electrochemical sensor using nanosilica and a newly synthesized Schiff base for simultaneous determination of Cd2+, Cu2+ and Hg2+ ions in water and some foodstuff samples. Anal. Chim. Acta 771, 21–30. Afkhami, A., Soltani-Felehgari, F., Madrakian, T., Ghaedi, H., Rezaeivala, M., 2013b. Fabrication and application of a new modified electrochemical sensor using nanosilica and a newly synthesized Schiff base for simultaneous determination of Cd2+, Cu2+ and Hg2+ ions in water and some foodstuff samples. Anal. Chim. Acta 771, 21–30. Afkhami, A., Felehgari, F.S., Madrakian, T., Ghaedi, H., Rezaeivala, M., 2013c. Fabrication and application of a new modified electrochemical sensor using nanosilica and a newly synthesized Schiff base for simultaneous determination of Cd2+, Cu2+ and Hg2+ ions in water and some foodstuff samples. Anal. Chim. Acta 771, 21–30. Alizadeh, T., Amjadi, S., 2011. Preparation of nano-sized Pb2+ imprinted polymer and its application as the chemical interface of an electrochemical sensor for toxic lead determination in different real samples. J. Hazard. Mater. 190, 451–459. Andrews, R.W., Johnson, D.C., 1975. Voltammetric deposition and stripping of selenium(iv) at a rotating gold- disk electrode in 0.1 m perchloric acid. Anal. Chem. 47, 294–299. Anık, U., Timur, S., 2007. α-Glucosidase based bismuth film electrode for inhibitor detection. Anal. Chim. Acta 598, 143–146. Anık, U.S., Timur, Meliha, C., Mubukc, u., Merkoc, i.A., 2008. The usage of a bismuth film electrode as transducer in glucose biosensing. Microchim. Acta 160, 269–273. Aragay, G., Pons, J., Merkoçi, A., 2011a. Recent trends in macro- micro-, and nanomaterials-based tools and strategies for heavy-metal detection. Chem. Rev. 111, 3433–3458. Aragay, G., Pons, J., Merkoci, A., 2011b. Enhanced electrochemical detection of heavy metals at heated graphite nanoparticle based screen printed electrodes. J. Mater. Chem. 21, 4326–4331. Arduini, F., Majorani, C., Amine, A., Moscone, D., Palleschi, G., 2011. Hg2+ detection by measuring thiol groups with a highly sensitive screen-printed electrode modified with a nanostructured carbon black film. Electrochim. Acta 56, 4209–4215. Array, G., Merkoci, A., 2012. Nanomaterials application in electrochemical detection of heavy metals. Electrochim. Acta 84, 49–61. Asadnia, M., Myers, M., Akhavan, N.D., O' Donnell, K., Umana-Membreno, G.A., Mishra, U.K., Nener, B., Baker, M., Parish, G., 2016. Mercury(II) selective sensors based on AlGaN/GaN transistors. Anal. Chim. Acta xxx, 1–7. Avuthu, S.G.R., Narakathu, B.B., Eshkeiti, A., Emamian, S., Bazuin, B.J., Joyce, M.,

452

Biosensors and Bioelectronics 94 (2017) 443–455

B. Bansod et al.

concentrations of lead by anodic-stripping voltammetry at the silver electrode. Anal. Chim. Acta 385, 325–335. Kong, R., Zhang, X., Zhang, L., Jin, X., Huan, S., Shen, G., Yu, R., 2009. An ultrasensitive electrochemical “turn-on” label-free biosensor for Hg2+with AuNP - functionalized reporter DNA as a signal amplifier. Chem. Commun., 5633–5635. Krolicka, A., Bobrowski, A., Kalcher, K., Mocak, J., Svancara, I., Vytras, K., 2003. Electroanalysis 15, 1859. Kudr, Jiri, Nguyen, Hoai Viet, Gumulec, Jaromir, Nejdl, Lukas, Blazkova, Iva, RuttkayNedecky, Branislav, Hynek, David, Kynicky, Jindrich, Adam, Vojtech, Kizek, Rene, 2015. Simultaneous automatic electrochemical detection of zinc, cadmium, copper and lead ions in environmental samples using a thin-film mercury electrode and an artificial neural network. Sensors 15, 592–610. Le, T.S., DaCosta, P., Huguet, P., Sistat, P., Pichot, F., Silva, F., 2012. Upstream microelectrodialysis for heavy metals detection on boron doped diamond. J. Electroanal. Chem. 670, 50–55. Lee, G.J., Kim, C.K., Lee, M.K., Rhee, C.K., 2010. Simultaneous voltammetric determination of zn, Cd and Pb at bismuth nanopowder electrodes with various particle size distributions. Electroanalysis 22 (5), 530–535. Lezi, N., Economou, A., Dimovasilis, P., Trikalitis, P.N., Prodromidis, M.I., 2012. Disposable screen-printed sensors modified with bismuth precursor compounds for the rapid voltammetric screening of trace Pb(II) and Cd(II). Anal. Chim. Acta 728, 1–8. Li, F., Yang, L., Chen, M., Qian, Y., 2013. Ultrasensitive label-free electrochemical immunosensor based on multifunctionalized graphene nanocomposites for the detection of alpha fetoprotein, Tang, B. Biosens. Bioelectron. 41, 903–906. Lin, M., Cho, M.S., Choe, W.S., Son, Y., Lee, Y., 2009. Electrochemical detection of copper ion using a modified copolythiophene electrode. Electrochim. Acta 54, 7012–7017. Lin, Y.-W., Huang, C.-C., Chang, H.-T., 2011. Gold nanoparticle probes for the detection of mercury, lead and copper ions. Analyst 136, 863–871. Lindfors, T., Szucs, J., Sundfors, F., Gyurcsanyi, R.E., 2010. Polyaniline nanoparticlebased solid-contact silicone rubber ion-selective electrodes for ultratrace measurements. Anal. Chem. 82, 9425. Liu, S., Kang, M., Yan, F., Peng, D., Yang, Y., He, L., Wang, M., Fang, S., Zhang, Z., 2015. Electrochemical DNA biosensor based on microspheres of cuprous oxide and nanochitosan for Hg(II) Detection. Electro. Acta 160, 64–73. Locatelli, C., Melucci, D., 2013. Voltammetric method for ultra-trace determination of total mercury and toxic metals in vegetables: comparison with spectroscopy. Cent. Eur. J. Chem. 11, 790–800. Losev, V.N., Buyko, O.V., Trofimchuk, A.K., Zuy, O.N., 2015. Silica sequentially modified with polyhexamethylene guanidine and arsenazo I for preconcentration and ICPOES determination of metals in natural waters. Micro Chem. J. 123, 84–89. Magnier, A., Billon, G., Louis, Y., Baeyens, W., Elskens, M., 2011. On the liability of dissolved Cu, Pb and Zn in freshwater: optimization and application to the Deûle(France). Talanta 86, 91–98. Maria, L., 2011. Biosens. Environ. Appl., 1–16. Mashhadizadeh, M.H., Khani, H., 2010. Sol-Gel-Au nano-particle modified carbon paste electrode for potentiometric determination of sub ppb level of Al(III). Anal. Methods 2, 24. Mashhadizadeh, M.H., Talemi, R.P., 2011. Used gold nano-particles as an on/off switch for response of a potentiometric sensor to Al(III) or Cu(II) metal ions. Anal. Chim. Acta 692, 109. Mayorga-Martinez, C.C., Cadevall, M., Guix, M., Ros, J., Merkoc, i., A., 2013. Bismuth nanoparticles for phenolic compounds biosensing application. Biosens. Bioelectron. 40, 57–62. Mehran, J., Faten, D., Alireza, B., Ganjali, M.R., Parviz, N., Ziarani, G.M., Marzieh, C., Jahangir, A.A., 2009. Potentiometric detection of mercury (II) ions using a carbon paste electrode modified with substituted thiourea-functionalized highly ordered nanoporous silica. Anal. Sci. 25, 789–794. Mohammadi, H., Amine, A., Cosnier, S., Mousty, C., 2005. Mercury- enzyme inhibition assays with an amperometric sucrose biosensor based on atrienzymatic-clay matrix. Anal. Chim. Acta543, 143–149. Nasraoui, R., Floner, D., Geneste, F., 2010. Improvement in performance of a flow electrochemical sensor by using carbamoyl-arms polyaza macrocycle for the preconcentration of lead ions onto the electrode. Electrochem. Commun. 12, 98–100. Nejdi, L., Ruttkay-Nedecky, B., Kudr, J., Kremplova, M., et al., 2013. Behaviour of zinc complexes and zinc sulphide nanoparticles revealed by using screen printed electrodes and spectrometry. Sensors 13, 14417–14437. Nejdi, L., Kudr, J., Cihalova, K., Chudobova, D., et al., 2014. Remote-controlled robotic platform Orpheus as a new tool for detection of bacteria in the environment. Electrophoresis 35, 2333–2345. Niu, P., Sánchez, C.F., Gich, M., Ayora, C., Roig, A., 2015. Electroanalytical assessment of heavy metals in waters with bismuth nanoparticle-porous carbon paste electrodes. Electrochim. Acta 165, 155–161. Nolan, M.A., Kounavis, S.P., 1999. Microfabricated array of iridium microdisks as a substrate for direct determination of Cu2+ or Hg2+ using square-wave anodic stripping voltammetry. Anal. Chem. 71, 3567–3573. Orazem, M.E., Tribollet, B., 2008. Electrochemical impedance spectroscopy. Analysis, 560. Ottakam Thotiyl, M.M., Basit, H., Sanchez, J.A., Goyer, C., Coche-Guerente, L., Dumy, P., 2012. Multilayer assemblies of polyelectrolyte-gold nanoparticles for the electrocatalytic oxidation and detection of arsenic (III). J. Colloid Interface Sci. 383, 130–139. P. Kissinger, W.R. Heineman, Laboratory Techniques in Electroanalytical Chemistry, 1996,1008.

Gao, A., Tang, C.X., He, X.W., Yin, X.B., 2013. Electrochemiluminescent lead biosensor based on GR-5 lead-dependent DNAzyme for Ru(phen)3(2+) intercalation and lead recognition. Analyst 138, 263–268. Gill, R., Zayats, M., Willner, I., 2008. Semiconductor quantum dots for bioanalysis. Angew. Chem. Int. Ed. 47, 7602–7625. Gong, T., Liu, J., Liu, X., Jie Liu, Xiang, J., Wu, Y., 2016. A sensitive and selective platform based on CdTe QDs in the presence of L-cysteine for detection of silver, mercury and copper ions in water and various drinks. Food Chem. 213, 306–312. Gozzo, M.L., Colacicco, L., Calla, C., Barbaresi, G., Parroni, R., Giardina, B., Lippa, S., 1999. Determination of copper, zinc, and selenium in human plasma and urine samples by potentiometric stripping analysis and constant current stripping analysis. Clin. Chim. Acta 285, 53. Granger, M.C., Witek, M., Xu, J., Wang, J., Hupert, M., Hanks, A., Koppang, M.D., Butler, J.E., Lucazeau, G., Mermoux, M., Strojek, J.W., Swain, G.M., 2000. Standard electrochemical behavior of high-quality, boron-doped polycrystalline diamond thinfilm electrodes. Anal. Chem. 72, 3793–3804. Gumpu, M.B., Sethuraman, S., Krishnan, U.M., Rayappan, J.B.B., 2015. A review on detection of heavy metal ions in water - an electrochemical approach. Sens. Actuators B 213, 515–533. Guo, J., Chai, Y., Yuan, R., Song, Z., Zou, Z., 2011. Lead (II) carbon paste electrode based on derivatized multi-walled carbon nanotubes: application to lead content determination in environmental samples. Sens. Actuators B 155, 639. Guo, X., Yun, Y., shanov, V.N., Halsall, H.B., Heineman, W.R., 2011. Determination of trace metals by anodic stripping voltammetry using a carbon nanotube tower electrode. Electroanalysis 23, 1252–1259. Guo, Z., Seol, M.-L., Gao, C., Gim, M.-S., Ahn, J.H., Choi, Y.-K., Huang, X.-J., 2016a. Functionalized porous Si nanowires for selective and simultaneous electrochemical detection of Cd(II) and Pb(II) ions. Electrochim. Acta 211, 998–1005. Guo, Z., Seol, M.L., Gao, C., Kim, M.S., Ahn, J.H., Choi, Y.K., Huang, X.J., 2016b. Functionalized porous Si nanowires for selective and simultaneous electrochemical detection of Cd(II) and Pb(II) ions. Electrochim. Acta 211, 998–1005. Gupta, V.K., Sethi, B., Upadhyay, N., Kumar, S., Singh, R., Singh, L.P., 2011. Iron (III) selective electrode based on S-Methyl N- (Methylcarbamoyloxy) thioacetimidate as a sensing material. Int. J. Electrochem. Sci. 6, 650–663. Harvey, David, Electrochemical Methods, Analytical chemistry 2 667-781. Herdan, J., Feeney, R., Kounaves, S.P., Flannery, A.F., Storment, C.W., Kovacs, G.T.A., Darling, R.B., 1998. Field evaluation of an electrochemical probe for in-situ determination of heavy metals in ground water. Environ. Sci. Technol. 32, 131–136. Huang, H., Chen, T., Liu, X., Ma, H., 2014. Ultrasensitive and simultaneous detection of heavy metal ions based on three-dimensional graphene-carbon nanotubes hybrid electrode materials. Anal. Chim. Acta 852, 45–54. Huang, M.R., Ding, Y.B., Li, X.G., 2014. Combinatorial screening of potentiometric Pb(II) sensors from polysulfoaminoanthraquinone solid ionophore. ACS Comb. Sci. 16, 128–138. Injang, U., Noyrod, P., Siangproh, W., Dungchai, W., Motomizu, S., Chailapakul, O., 2010b. Determination of trace heavy metals in herbs by sequential injection analysisanodic stripping voltammetry using screen-printed carbon nanotubes electrodes. Anal. Chim. Acta 668, 54–60. Jagner, D., 1982. Potentiometric stripping analysis. A review. Analyst 107, 593. Jia, J., Chen, H.G., Feng, J., Lei, J.L., Luo, H.Q., Li, N.B., 2016. A regenerative ratiometric electrochemical biosensor for selective detecting Hg2þ based on Yshaped/hairpin DNA transformation. Anal. Chim. Acta xxx, 1–7. Jothimuthu, P., Wilson, R.A., Herren, J., Haynes, E.N., Heineman, W.R., Papautsky, I., 2011. Lab-on-a-chip sensor for detection of highly electronegative heavy metals by anodic stripping voltammetry. Biomed. Micro. 13, 695–703. Jovanovic, Z., Buica, G.-O., Miskovicstankovic, V., Ungureanu, E.-M., Amarandei, C.-A., 2013. Electrochemical Impedance Spectroscopy investigations on glassy carbon electrodes modified with poly(4-azulen-1-yl-2,6-bis(2- thienyl)pyridine). U. P. B. Sci. Bull. B 75, 125–134. Kefala, G., Economou, A., Voulgaropoulos, A., Sofoniou, M., 2003. A study of bismuthfilm electrodes for the detection of trace metals by anodic stripping voltammetry and their application to the determination of Pb and Zn in tapwater and human hair. Talanta 61, 603–610. Kenawy, I.M.M., Hafez, M.A.H., Akl, M.A., Lashein, R.R., 2000. Determination by AAS of some trace heavy metal ions in some natural and biological samples after their preconcentration using newly chemically modified chloromethylated PolystyrenePAN Ion-Exchanger. Anal. Sci. 16, 493–500. Kestwal, D.B., Karve, M.S., Kakade, B., Pillai, V.K., 2008. Invertase inhibition based electrochemical sensor for the detection of heavy metal ions in aqueous system: application of ultra-microelectrode to enhance sucrose biosensor's sensitivity. Biosens. Bioelectron. 24, 657–664. Khadro, B., Sikora, A., Loir, S., Errachid, A., Garrelie, F., Donnet, C., 2011. Electrochemical performances of B-doped and undoped diamond-like carbon (DLC) films deposited by fem to second pulsed laser ablation for heavy metal detection using square wave anodic stripping voltammetric (SWASV) technique. Sens. Actuators B 155, 120–125. Khani, H., Rofouei, M.K., Arab, P., Gupta, V.K., Vafaei, Z., 2010. Multi-walled carbon nanotubes-ionic liquid-carbon paste electrode as a super selectivity sensor: application to potentiometric monitoring of mercury ion (II). J. Hazard. Mater. 183, 402–409. Kim, H.N., Ren, W.X., Kim, J.S., Yoon, J., 2012. Fluorescent and colorimetric sensors for detection of lead, cadmium, and mercury ions. Chem. Soc. Rev. 41, 3210–3244. Kim, T.H., Lee, J., Hong, S., 2009. Highly selective environmental nanosensors based on anomalous response of carbon nanotube conductance to mercury ions. J. Phys. Chem. C. 113, 19393. Kirowa-Eisner, E., Brand, M., Tzur, D., 1999. Determination of sub-nanomolar

453

Biosensors and Bioelectronics 94 (2017) 443–455

B. Bansod et al.

Tanguy, V., Waeles, M., Vandenhecke, J., Riso, R.D., 2010. Determination of ultra-trace Sb(III) in seawater by stripping chronopotentiometry (SCP) with a mercury film electrode in the presence of copper. Talanta 81, 614–620. Tarley, C.R.T., Santos, V.S., Baeta, B.E.L., Pereira, A.C., Kubota, L.T., Hazard. Mater, J., 2009. Simultaneous determination of zinc, cadmium and lead in environmental water samples by potentiometric stripping analysis (PSA) using multiwalled carbon nanotube electrode. J. Hazard. Mater. 169, 256–262. Tekaya, N., Saiapina, O., Ben Ouada, H., Lagarde, F., Ben Ouada, H., Jaffrezic Renault, N., 2013. Ultra-sensitive conductometric detection of heavy metals based on inhibition of alkaline phosphatase activity from Arthrospira platensis. Bioelectrochemistry 90, 24–29. Tesarova, E., Baldrianova, L., Hocevar, Samo B., Svancara, I., Vytras, K., Ogorevc, B., 2009. Anodic stripping voltammetric measurement of trace heavy metals at antimony film carbon paste electrode. Electrochim. Acta 54, 1506–1510. Toghill, K.E., Xiao, L., Wildgoose, G.G., Compton, R.G., 2009. Electroanalytical determination of cadmium(II) and lead(II) using an antimony nanoparticle modified boron-doped diamond electrode. Electroanalysis 21, 1113–1118. Tonle, I.K., Letaief, S., Ngameni, E., Walcarius, A., Detellier, 2011. Square wave voltammetric determination of lead (II) ions using a carbon paste electrode modified by a thiol-functionalized kao linite. Electroanalysis 23, 245–252. Town, R.M., van Leeuwen, H.P., 2001. Fundamental features of metal ion determination by stripping chronopotentiometry. J. Electroanal. Chem. 509, 58. Town, R.M., van Leeuwen, H.P., 2002. Effects of adsorption in stripping chronopotentiometric metal speciation analysis. J. Electroanal. Chem. 523, 1–15. Trindade, A.S.N., Dantas, A.F., Lima, D.C., Ferreira, S.L.C., Teixeira, L.S.G., 2015. Multivariate optimization of ultrasound-assisted extraction for determination of Cu, Fe, Ni and Zn in vegetable oils by high-resolution continuum source atomic absorption spectrometry. Food Chem. 185, 145–150. Turdean, G.L., 2011. Design and development of biosensors for the detection of heavy metal toxicity. Int. J. Electrochem., 1–15. U.S, 2009. EPA National Primary Drinking Water Regulations. Viltchinskaia, E.A., Zeigman, L.L., Morton, S.G., 1995. Application of stripping voltammetry for the determination of mercury. Electroanalysis 7, 264–269. Wanekaya, A.K., 2011. Applications of nanoscale carbon-based materials in heavy metal sensing and detection. Analyst 136, 4383–4391. Wang, B., Chang, Y., Zhi, L., 2011. High yield production of graphene and its improved property in detecting heavy metal ions. New Carbon Mater. 26, 31–35. Wang, H., Wu, Z.K., Chen, B.B., He, M., Hu, B., 2015. Chip-based array magnetic solid phase micro extraction on-line coupled with inductively coupled plasma mass spectrometry for the determination of trace heavy metals in cells. Analyst 140, 5619–5626. Wang, J., 2005. Stripping analysis at bismuth electrodes: a review. Electroanalysis 17, 1341–1346. Wang, J., Tian, B., 1993. Mercury-free disposable lead sensors based on potentiometric stripping analysis at gold-coated screen-printed electrodes. Anal. Chem. 65, 1529–1532. Wang, J., Lu, J., Hocevar, S.B., Farias, P.A.M., Ogorevc, B., 2000. Bismuth-coated carbon electrodes for anodic stripping voltammetry. Anal. Chem. 72, 3218–3222. Wang, J., Lu, J., Hocevar, S.B., Ogorevc, B., 2001a. Bismuth-coated screen-printed electrodes for stripping voltammetric measurements of trace lead. Electroanalysis 13, 13–16. Wang, J., Lu, J., Kirgoz, U.A., Hocevar, S.B., Ogorevc, B., 2001b. Insights into the anodic stripping voltammetric behavior of bismuth film electrodes. Anal. Chim. Acta 434, 29–34. Wei, Y., Yang, R., Chen, X., Wang, L., Liu, J.H., Huang, X.J., 2012a. A cation trap for anodic stripping voltammetry: nh3–plasma treated carbon nanotubes for adsorption and detection of metal ions. Anal. Chim. Acta 755, 54–61. Wei, Y., Yang, R., Yu, X.Y., Wang, L., Liu, J.H., Huang, X.J., 2012b. Stripping voltammetry study of ultra-trace toxic metal ions on highly selectively adsorptive porous magnesium oxide nanoflowers. Analyst 137, 2183–2191. Wei, Y., Gao, C., Meng, F.L., Li, H.H., Wang, L., Liu, J.H., Huang, X.J., SnO2/reduced, J., 2012c. graphene oxide nanocomposite for the simultaneous electrochemical detection of cadmium(II), lead(II), copper(II), and mercury(II): an interesting favorable mutual interference. Phys. Chem. C116, 1034–1041. WHO, 2011. Guidelines for Drinking-water Quality, 4th edition. Xu, R.X., Yu, X.Y., Gao, C., Jiang, Y.J., Han, D.D., Liu, J.H., Huang, X.J., 2013. Nonconductive nanomaterial enhanced electrochemical response in stripping voltammetry: the use of nanostructured magnesium silicate hollow spheres for heavy metal ions detection. Anal. Chim. Acta 790, 31–38. Xuan, F., Luo, X., Hsing, I.-M., 2013. Conformation-dependent Exonuclease III activity mediated by metal ions reshuffling on thymine-rich DNA duplexes for an ultrasensitive electrochemical method for Hg2+ detection. Anal. Chem. 85, 4586–4593. Yasri, N.G., Halabi, A.J., Istamboulie, G., Noguer, T., 2011. Chronoamperometric determination of lead ions using PEDOT: pss modified carbon electrodes. Talanta 85, 2528–2533. Zaidi, M.J., Khan, A., Siddiqui, M.S., Khadairi, Al, 2011. Genotoxicity of heavy metal contaminated soils, Environ. Pollut 20, 323–342. Zaouak, O., Authier, L., Cugnet, C., Castetbon, A., Electroanalytical, P.G.M., 2010. device for cadmium speciation in waters. Part1: development and characterization of a reliable screen-printed sensor. Electroanalysis 22, 1151–1158. Zhang, B., Chen, J.D., Han Zhu, Ting Yang, T., Zou, M., Zhang, M., Du, M.L., 2016b. Facile and green fabrication of size-controlled AuNPs/CNFs hybrids for the highly sensitive simultaneous detection of heavy metal ions. Electrochim. Acta 196, 422–430. Zhang, Y., Liu, Y., Ji, X., Banks, C.E., Zhang, W., 2011. Sea cucumber-like

Pan, D., Wang, Y., Chen, Z., Lou, T., Qin, W., 2009. Nanomaterials/ionophore-based electrode for anodic stripping voltammetric determination of lead: an electrochemical sensing platform toward heavy metals. Anal. Chem. 81, 5088–5094. Parat, C., Authier, L., Aguilar, D., Companys, E., Puy, J., Galceran, J., 2011a. Direct determination of free metal concentration by implementing stripping chronopotentiometry as the second stage of AGNES. Analyst 136, 4337–4343. Parat, C., Schneider, A., Castetbon, A., Potin-Gautier, M., 2011b. Determination of trace metal speciation parameters by using screen-printed electrodes in stripping chronopotentiometry without deaerating. Anal. Chim. Acta 688, 156–162. Parra, E.J., Blondeau, P., Crespo, G.A., Rius, F.X., 2011. An effective nanostructured assembly for ion-selective electrodes. An ionophore covalently linked to carbon nanotubes for Pb2+ determination. Chem. Commun. 47, 2438. Pauliukaite, R., Hocevar, S.B., Ogorevc, B., Wang, J., 2004. Characterization and applications of a bismuth bulk electrode. Electroanalysis 16, 719–723. Pereira, E., Rivas, B.L., Heitzmann, M., Moutet, J.C., Bucher, C., Royal, G., 2011. Complexing polymer films in the preparation of modified electrodes for detection of metal ions. Macromol. Symp. 304, 115–125. Pohl, P., 2009. Determination of metal content in honey by atomic absorption spectroscopy. Trends Anal. Chem. 28, 117–128. Prabhakar, S., Singh, A.K., Pooni, D.S., 2012. Effect of environmental pollution on animal and human health: a review. Ind. J. Anim. Sci. 82, 244–255. Pujol, L., Evrard, D., Serrano, K.G., Freyssinier, M., Cizsak, A.R., Gros, P., 2014. Electrochemical sensors and devices for electrochemical assay in water: the French groups contribution. Front. Chem., Anal. Chem. 19, 1–24. Radu, A., Diamond, D., 2007. In: Alegret, S., Merkoci, A. (Eds.), Ion Selective Electrodes in Trace Level Analysis of Heavy Metals: Potentiometry for XXI Century 49. Comprehensive Analytical Chemistry, 25–52. Research, P.A., 1987. Application note AC-1 subject: basics of electrochemical impedance spectroscopy. Princet. Appl. Res., 1–13. Rico, M.A.G., Olivares-Mar´ın, M., Gil, E.P., 2009. Modification of carbon screen-printed electrodes by adsorption of chemically synthesized Bi nanoparticles for the voltammetric stripping detection of Zn(II), Cd(II) and Pb(II). Talanta 80, 631–635. Rosolina, S.M., Chambers, J.Q., Lee, C.W., Xue, Z.L., 2015. Direct determination of cadmium and lead in pharmaceutical ingredients using anodic stripping voltammetry in aqueous and DMSO/water solutions. Anal. Chim. Acta 893, 25–33. Rouis, A., Echabaane, M., Sakly, N., Dumazet-Bonnamour, I., Ben Ouada, H., 2013. Electrochemical analysis of a PPV derivative thin film doped with beta- ketoimine calix[4]arene in the dark and under illumination for the detection of Hg2+ ions. Synth. Met 164, 78–87. Roy, S.P., 2010. Overview of heavy metals and aquatic environment with notes on their recovery. Ecoscan 4, 235–240. S vancara, I., Prior, C., Hocˇevar, S.B., Wang, J., 2010. A decade with bismuth-based electrodes in electroanalysis. Electroanalysis 22, 1405–1420. Sadhukhan, M., Barman, S., 2013. Bottom-up fabrication of two-dimensional carbon nitride and highly sensitive electrochemical sensors for mercuric ions. J. Mater. Chem. A1, 2752–2756. Sahoo, P., Panigrahy, B., Sahoo, S., Satpati, A., Li, D., Bahadur, D., 2013. In situ synthesis and properties of reduced graphene oxide/Bi nanocomposites: As an electroactive material for analysis of heavy metals. Biosens. Bioelectron. 43, 293–296. Sbartai, A., Namour, P., Errachid, A., Krejci, J., Sejnohova, R., Renaud, L., 2012. Electrochemical boron - doped diamond film microcells micromachined with fem to second laser: application to the determination of water framework directive metals. Anal. Chem. 84, 4805–4811. Serrano, N., Manuel Dıaz-Cruz, J., Arino, C., Esteban, M., 2003. Comparison of constantcurrent stripping chronopotentiometry and anodic stripping voltammetry in metal speciation studies using mercury drop and film electrodes. J. Electroanal. Chem. 560, 105–116. Show, Y., Witek, M.A., Sonthalia, P., Swain, G.M., 2003. Characterization and electrochemical responsiveness of boron-doped nanocrystalline diamond thin-film electrodes. Chem. Mater. 15, 879. Silva, E.L., Roldan, P.S., Gine, M.F., 2009. Simultaneous preconcentration of copper, zinc, cadmium, and nickel in water samples by cloud point extraction using 4-(2pyridylazo)-resorcinol and their determination by inductively coupled plasma optic emission spectrometry. J. Hazard. Mater. 171, 1133–1138. Sitko, R., Janik, P., Zawisza, B., Talik, E., Margui, E., Queralt, I., 2015. Green approach for ultra trace determination of divalent metal ions and arsenic species using totalreflection X-ray fluorescence spectrometry and mercapto-modified graphene oxide nanosheets as a novel adsorbent. Anal. Chem. 87, 3535–3542. Soldatkin, O.O., Kucherenko, I.S., Pyeshkova, V.M., Kukla, A.L., Jaffrezic- Renault, N., El’skaya, A.V., 2012. Novel conductometric biosensor based on three-enzyme system for selective determination of heavy metal ions. Bioelectrochemistry 83, 25–30. Standard methods for the examination of water & wastewater, 2012. American Public Health Association (APHA), American Water Works Association (AWWA) & Water Environment Federation 22 (WEF). Szłyk, E., Czerniak, A.S., 2004. Determination of cadmium, lead, and copper in margarines and butters by galvanostatic stripping chronopotentiometry. J. Agric. Food Chem. 52, 4064–4071. Szłyk, E., Czerniak Szydłowska, A., 2004. Determination of cadmium, lead, and copper in margarines and butters by galvanostatic stripping chronopotentiometry. J. Agric Food Chem. 52 (13), 4064–4071. Tag, K., Riedel, K., Bauer, H.-J., Hanke, G., Baronian, K.H.R., Kunze, G., 2007. Amperometric detection of Cu2+ by yeast biosensors using flow injection analysis (FRA). Sens. Actuators B: Chem. 122, 403–409. Tang, S., Tong, P., Li, H., Tang, J., Zhang, L., 2013. Ultrasensitive electrochemical detection of Pb2+ based on rolling circle amplification and quantum dots tagging. Biosens. Bioelectron. 42, 608–611.

454

Biosensors and Bioelectronics 94 (2017) 443–455

B. Bansod et al.

Zou, G., Ju, H., 2004. Electrogenerated chemiluminescence from a cdse nanocrystal film and its sensing application in aqueous solution. Anal. Chem. 76, 6871–6876. Zou, Z., Jang, A., Macknight, E., Do, P., Wu, J., Bishop, P., Ahn, C., 2008. Environmentally friendly disposable sensors with microfabricated on-chip planar bismuth electrode for in situ heavy metal ions measurement. Sens. Actuators B 134, 18–24.

hydroxyapatite: cation exchange membrane-assisted synthesis and its application in ultra-sensitive heavy metal detection [J]. Chem. Commun. 47, 4126–4128. Zhou, F., Wei, Q., 2008. Scaling laws for nanoFET sensors. Nanotechnology 19, 015504. Zhuo, L., Huang, Y., Cheng, M.S., Lee, H.K., Toh, C., 2010. Nanoarray membrane sensor based on a multilayer design for sensing of water pollutants. Anal. Chem. 82, 4329–4332.

455