- Email: [email protected]
Simultaneous Detection of Hydroquinone, Catechol and Resorcinol by an Electrochemical Sensor Based on Ammoniated-Phosphate Buffer Solution Activated Glassy Carbon Electrode
CHINESE JOURNAL OF ANALYTICAL CHEMISTRY Volume 47, Issue 9, September 2019 Online English edition of the Chinese language journal
Cite this article as: Chinese J. Anal. Chem., 2019, 47(9): e19113–e19120
RESEARCH PAPER
Simultaneous Detection of Hydroquinone, Catechol and Resorcinol by an Electrochemical Sensor Based on Ammoniated-Phosphate Buffer Solution Activated Glassy Carbon Electrode LIU Hong-Ying1, ZHU Lang-Lang1, HUANG Zhi-Heng1, QIU Yu-Bing1, XU Han-Xiao1, WEN Jia-Jun1, XIONG Wei-Wei3, LI Li-Hua1,*, GU Chun-Chuan2,* 1
College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Hangzhou 310018, China Deparment of Clinical Laboratory, Hangzhou Cancer Hospital, Hangzhou 310002, China 3 School of Environmental & Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003, China 2
Abstract:
An electrochemical sensor was successfully fabricated by coupled ammoniated modification with PBS activation on glassy
carbon electrodes (CA-GCE) and characterized by electrochemical impedance spectra. The CA-GCE showed outstanding electrochemical performance, and was applied to simultaneous detection of resorcinol (RC), catechol (CC) and hydroquinone (HQ), which could be ascribed to new active sites by the introduction of amino and oxygen-containing groups and H-bonds formed between hydroxyl groups of RC, CC, and HQ with amine, hydroxyl and carboxyl groups of CA-GCE. The reaction kinetics of RC, CC, and HQ and their reaction on CA-GCE were studied. Experimental results showed that the electrochemical reaction was adsorption controlled. Under the optimal conditions, the linear detection ranges for RC, CC, and HQ were 5–200 μM, 10–300 μM, and 1–300 μM, respectively, with their detection limits of 0.47, 0.23 and 0.46 μM, respectively. Interference and repeatability was further investigated. This strategy opened a new horizon for qualitative and quantitative detection of dihydroxy benzene. Key Words:
Ammoniated; Phosphate buffer solution activation; Hydroquinone; Catechol; Resorcinol
1 Introduction Resorcinol (RC), catechol (CC) and hydroquinone (HQ) represent three isomers of dihydroxy benzene. They are commonly applied in the field of dye, pharmaceuticals, cosmetics, antioxidants, pesticides, and rubbers industries [1]. However, these compounds can harm human health and pollute the environment, and are thus regarded as the significant environmental contaminants by the U.S. Environmental Protection Agency[2,3]. So, it is very important to distinguish and detect concentrations of these organic
substances. Plenty of methods and techniques have been developed for detection and identification of these organics in recent years, including high-performance liquid chromatography (HPLC)[4], spectrophotometry[5], chromatography[6], chemiluminescence[7] and electrochemical method[8-12]. HPLC is widely applied due to its high efficiency and sensitivity[13], but is hindered by the prolonged testing and exorbitant costs. Spectrophotometric detection is based on the specific wavelength of the material, but it is difficult to distinguish isomers. Chemiluminescent method has high sensitivity and convenient operation, but is unable to distinguish isomers with
________________________ Received 6 July 2018; accepted 28 June 2019 *Corresponding author. Email: [email protected]; [email protected] This work was supported by the Science and Technology Program of Zhejiang Province of China (No. LGF18H200005), the National Natural Science Foundation of China (Nos. 21405029, 617310008), the Medical and Health Technology Development Program of Zhejiang Province (No. 2017KY533), and the Young and Middle-aged Academic Leaders of Zhejiang Province, China. Copyright © 2019, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences. Published by Elsevier Limited. All rights reserved. DOI: 10.1016/S1872-2040(19)61183-7
LIU Hong-Ying et al. / Chinese Journal of Analytical Chemistry, 2019, 47(9): e19113–e19120
similar chemical reaction conditions. The electrochemical methods have attracted more attentions in recent years due to its simplicity, convenience, low-cost maintenance, high selectivity, wide detection range and high sensitivity[14,15]. Until now, the fabrication of modified glassy carbon electrode (GCE) in the detection of dihydroxy benzene isomers used a variety of materials, such as carbon material[16‒22], bimetallic nanostructured materials[23], doping graphite materials[24,25], metal oxides and sulfides[26‒30] and so on. Although lower detection limits and wider detection ranges were obtained by the above electrodes, their complex operation and ease of peeling off when testing severely limited the stability and sensitivity[31]. Therefore, activated electrodes which can directly modify related groups on the surface of glassy carbon electrode have been developed[8,32‒36]. Ammonification[37,38], sulfuric acid activation[39], and phosphate buffer solutions (PBS) activation[8] were the three main forms. These methods greatly simplified the modifying process. In addition, some nitrogen-containing groups and oxygencontaining groups which modified on the surface of the electrode[40] can improve the efficiency of electron transfer in the electrode. So, it is vital for exploring new activating methods. In this work, a novel composite activation electrode (CA-GCE) was successfully developed, as shown in Fig.1. First, primary and secondary amino groups were introduced into the surfaces of GCE by dripping it in an ammonium carbamate solution and then assisting electrooxidation treatment. Then, the above aminated GCE was further activated by simple anodic and cathodic polarization in PBS to introduce some oxygen-containing groups. Subsequently, the CA-GCE featured electrochemical impedance spectra (EIS). The CA-GCE exhibited good electrochemical behavior towards the electro-oxidation of RC, CC, and HQ, which
Fig.1
could be ascribed to that the synergy effect between amine groups and oxygen-containing groups could expand the surface area of electrode and increase the efficiency of electron transfer. Based on this, a novel electrochemical biosensor was developed for determination of concentrations of RC, CC and HQ.
2 Experimental 2.1
Instruments and reagents
Electrochemical experiments were conducted on a CS100 electrochemical workstation (Wuhan CorrTest Instruments Co., Ltd., China) employing a standard three-electrode system with the GCE as working electrode (WE), a platinum electrode as counter electrode (CE), and an Ag/AgCl electrode as reference electrode (RE). HQ, CC and RC with analytical grade were obtained from the Macklin Co., Ltd. (Shanghai, China). Ammonium carbamate was from the Aladdin group in Shanghai, China. PBS with different pH values were prepared by mixing 0.1 M NaH2PO4 and K2HPO4 in different ratios. Each solution was formulated using deionized water. All chemicals used were of at least analytical grade. 2.2
Fabrication of CA-GCE
After being polished by 0.30 and 0.05 μm Al2O3 powder, the GCE was ultrasonically cleaned with anhydrous ethanol and deionized water for 8 min each. Then, the GCE was dried with N2 and placed in ammonium carbamate solution (0.1 M). Then, using the constant potential method, the electrode was
Schematic of fabrication of CA-GCE and detection of RC, CC and HQ
LIU Hong-Ying et al. / Chinese Journal of Analytical Chemistry, 2019, 47(9): e19113–e19120
polarized at +1.1 V for 20 min, –1.0 V for 15 min to obtain an ammoniated electrode (Am-GCE). Finally, Am-GCE was further activated in PBS solution (0.1 M, pH 7) via the constant potential method at +1.7 V anodic polarization for 20 min, and cathodic polarization at ‒1.0 V for 15 min to obtain CA-GCE. For comparison, Am-GCE and PBS activated electrode (PGCE) was prepared by the first and second step. 2.3
Characterization of modified electrodes
EIS were tested in 0.1 M KCl solution containing 20 mM K3Fe(CN)6/K4Fe(CN)6. 2.4
Detection of HQ, RC and CC in real samples
Tap water samples and the Yueya Lake water samples in Hangzhou Dianzi University were detected. Filter papers were used firstly to remove large particles. Then, various concentrations of HQ, RC and CC were spiked in the real water samples. Finally, CA-GCE was used to determine the concentrations of HQ, RC and CC and the recoveries were calculated.
3 3.1
Results and discussion Characterization of CA-GCE
EIS was explored to investigate the electrochemical behavior of electrodes. As shown in Fig.2A and Fig.2B, CA-GCE had the lowest electron transfer resistance, indicating a highest charge transfer rate. This confirmed that the composite activation process could efficiently accelerate electron transfer rate of electrochemical probe Fe[CN]63‒/4‒. It might be due to the synergy effect between diverse groups of modification layer. 3.2
Electrochemical behaviors of RC, CC and HQ on CA-GCE
The cyclic voltammetry responses of 100 μM RC, CC and HQ on modified electrodes PGCE, Am-GCE, CA-GCE and bare
Fig.2
GCE in PBS (pH 7, 0.1 M) were analyzed. As shown in Fig.3, two redox peak pairs and an oxidation peak obviously appeared on both activated GCEs. For CC, the redox peak potential difference (ΔEp) was approximately 20–25 mV, 25–30 mV and 15–20 mV for PGCE, Am-GCE and CA-GCE, respectively. For HQ, ΔEp was approximately 23–28 mV, 25–30 mV, 20–25 mV and 20–25 mV for PGCE, Am-GCE, CA-GCE and bare GCE, respectively, while no distinct oxidation peak was found for bare GCE. This indicated good reversibility for the above activated GCE. However, the peak current of HQ on CA-GCE was about 1.85 and 1.54 times as those on Am-GCE and PGCE. The peak current of CC at CA-GCE was about 1.29 and 1.23 times as those on at Am-GCE and PGCE. This indicated the sensitivities of both CC and HQ at the CA-GCE were better than those of Am-GCE and PGCE. In summary, the CA-GCE showed an outstanding electrochemical behavior, indicating a promising potential for simultaneously detecting RC, CC and HQ. For PGCE, after electrochemical treatment, hydroxyl and carboxyl groups were introduced to the surface of the electrode. These abundant carboxyl and hydroxyl groups could greatly increase the electrochemical activity of PGCE. For Am-GCE, some primary amino groups and other N-containing groups were introduced to the surface of electrode by electrochemical polarization methods[8]. The introduction of these N-containing groups greatly improved the electrochemical performance of the electrode. But for CA-GCE, it might be ascribed to some of following reasons. First, the introduction of amino and oxygen-containing groups could supply new active sites, and thus accelerated the electron transport rate. Second, H-bonds were formed between hydroxyl groups of RC, CC and HQ with amine, hydroxyl and carboxyl groups of CA-GCE. These H-bonds could promote electron transfer rates. Third, the electrostatic interaction between these carboxyl groups (negative) and amino groups (positive) could enhance their electron transfer efficiency. Furthermore, the redox process of RC, CC, and HQ was also studied. As shown in Fig.3, they come forward one after another in the sequence of HQ, CC and RC. We analyzed various causes of this phenomenon on the basis theory of organic chemistry[41]. It was well known that -OH was a strong ortho-para substituent and had two effects on the benzene
(A) Nyquist plots of CA-GCE, PGCE, Am-GCE, and GCE. Frequency range: 0.1–1.0 ×105 Hz; (B) The enlarged view of (A)
LIU Hong-Ying et al. / Chinese Journal of Analytical Chemistry, 2019, 47(9): e19113–e19120
Fig.3
Cyclic voltammograms (CVs) for simultaneous detection of 100 μM RC, CC and HQ on Am-GCE, PGCE, CA-GCE and GCE in PBS (pH 7, 0.1 M). Scan rates: 50 mV s–1
ring. On one hand, the electronegativity of oxygen was so large that it produced an electron-induced effect. This effect could lower the electron cloud density on the benzene ring. On the other hand, a conjugated system was generated by the formation of p-π conjugate system between the lone pair of oxygen in ‒OH with π bond of benzene. This system could increase the electron cloud density of benzene ring, particularly for the ortho-position and para-position. For these two effects, the latter took the dominant position. Back to this point, [M]2‒ generated by HQ and CC formed a more stable quinone structure via electron transfer. This quinone structure was a very stable 8-atom conjugate system that contained six carbon atoms and two oxygen atoms. Thus, RC was the most difficult species to oxidize because the π-conjugation of keys did not pass between meta positions. Additionally, the oxidization of HQ was simpler than the oxidization of CC. 3.3
Effect of scan rates
The kinetic processes of RC, CC and HQ on CA-GCE were examined by studying various effects of scan rates on potential and peak currents[42]. CVs of 100 μM RC, CC and HQ in PBS (pH 7, 0.1 M) on the CA-GCE at various scan rates are displayed in Fig.4. It could be seen that oxidation peak current increased regularly with an increasing sweep rate.
Fig.4
As shown in Fig.4B and Fig.4C, the peak current and scan rate showed a linear relationship in the range of 10–90 mV s–1, indicating a surface-controlled mechanism[43]. The regression equations were ipa (μA) = (1.76 ± 0.09) + (0.15 ± 0.005)v (mV s‒1) for HQ, ipa (μA) = (1.30 ± 0.08) + (0.08 ± 0.002)v (mV s‒1) for CC, and ipa (μA) = (2.78 ± 0.06) + (0.06 ± 0.003)v (mV s‒1) for RC, with R2 of 0.993, 0.995 and 0.988, respectively. Furthermore, the peak current and the square root of the scan rate showed a linear relationship at 100–1000 mV s–1, revealing a diffusion-controlled mechanism[43]. The regression equations were ipa (μA) = (–4.55 ± 0.67) + (64.21 ± 1.68)v1/2 (V s‒1) for HQ, ipa (μA) = (–7.47 ± 0.32) + (53.32 ± 0.54)v1/2 (V s‒1) for CC, and ipa (μA) = (–7.27 ± 0.75) + (46.85 ± 1.62)v1/2 (V s‒1) for RC, with R2 of 0.993, 0.999 and 0.988, respectively. These variations demonstrated that CA-GCE had faster charge-transfer kinetics. In addition, it could be observed that there was a positive shift in the oxidation peaks potential and a negative shift in the reduction peaks potential of RC, CC, and HQ. Furthermore, the electrochemical redox reaction of CC on the CA-GCE (Fig.5) was explained according to ECEC mechanism[44]. The CC (I) could be oxidized to o-quinone (II), which was formed via rapid electron transfer (E1). Later, o-quinone (II) was followed by a 1,4-nucleophilic addition of primary ammonia on the CA-GCE to the quinone, producing the adduct (III) (C). Then the adduct (III) was oxidized to form quinonoids (IV) by electron transfer (E2). Finally, IV transformed to 3,4-diaminocatechol (V) by a 1,4-nucleophilic addition just like C above. Thus, the above reaction followed the ECEC mechanism proposed in Fig.5. With the generation of chemical reaction, the number of electron transfers in the redox process of CC increased from 2 to 4. The above results proved that the electrochemical reactions of CC on CA-GCE were controlled by the adsorption process, and two protons and two electrons attended the electrochemical oxidation. 3.4
Effect of pH value
It is generally believed that there is relationship between electrocatalytic properties of RC, CC, and HQ at CA-GCE and
(A) CVs of CA-GCE in PBS (pH 7.0, 0.1 M) containing 100 µM RC, CC and HQ at the scan rate of 10, 15, 20, 30, 50, 70, 90, 100, 150, 200, 250, 300, 350, 400, 500, 600, 700, 800 and 1000 mV s–1 (a‒t); Calibration plots of oxidation peak current for RC, CC and HQ vs scan rate at 0–90 mV s–1 (B) and 100–1000 mV s–1 (C), respectively
LIU Hong-Ying et al. / Chinese Journal of Analytical Chemistry, 2019, 47(9): e19113–e19120
Fig.5
Diagram of ECEC mechanism
pH. Furthermore, the concentration of H+ will affect the adsorption capacity of RC, CC and HQ[29]. Therefore, the effects of pH on both peak current and potential of RC, CC and HQ on CA-GCE were studied. Figure 6 shows CVs of CA-GCE in PBS (0.1 M) containing 100 µM RC, CC and HQ at various pH levels and their calibration plots. As shown in Fig.6B, the oxidation peak current of HQ and CC increased gradually as pH increased and leveled off at pH 6.18 and 7.00, respectively. However, the oxidation peak current of RC gradually decreased while pH was mounting. It might be ascribed to the fact that the electrooxidation reaction was difficult to occur at higher pH levels due to the shortage of protons. In summary, pH 7.00 was selected in the next experiments. Further studies about the connection between the oxidation peak potentials of HQ, CC and RC and pH were carried out. As shown in Fig.6C, there was a solid linear relationship between the oxidation peak potentials of HQ and CC as well as RC and pH. The regression equations were Epa (V) = (0.46 ± 0.011) – (0.049 ± 0.0017) pH for RC, Epa (V) = (0.61 ± 0.038) – (0.056 ± 0.005) pH for CC, and Epa (V) = (1.05 ± 0.015) – (0.061 ±0.0025) pH for HQ, with R2 of 0.994, 0.960 and 0.992 respectively. The slope of the above equations was nearly 59 mV/pH which was obtained from the equation ΔE/ΔpH = 2.303mRT/nF (m and n are the number of protons and electrons, respectively). It showed that two protons and two electrons process was involved in the electrochemical oxidation of HQ, CC and RC on CA-GCE[29].
Fig.6
3.5
Simultaneously detection of RC, CC and HQ
CV was employed to simultaneously detect RC, CC and HQ by CA-GCE with the scan rate of 50 mV s–1 in PBS (pH 7, 0.1 M). First, the concentrations of RC, CC or HQ were increased from 1 to 1000 µM while CC and HQ, RC and HQ, RC and CC two were kept at 100 µM. Then, the CV curves were drawn and the relationship between the concentration and peak current was examined. As shown in Fig.7A‒Fig.7F, there was a good linear relationship between the peak current and the concentration of RC, CC, or HQ. The regression equations were Ipa (μA) = (6.51 ± 0.18) + (0.059 ± 0.0035)CRC (μM), Ipa (μA) = (10.96 ± 0.46) + (0.066 ± 0.003)CCC (μM) and Ipa (μA) = (13.91 ± 0.15) + (0.046 ± 0.0016)CHQ (μM), with R2 of 0.983, 0.990 and 0.991, respectively. The limits of detection of RC, CC and HQ were 0.47, 0.23 and 0.46 μM (S/N = 3), respectively. Subsequently, the simultaneous detection of RC, CC and HQ was exploited through recording CV of CA-GCE by varying the concentrations of RC, CC and HQ. As shown in Fig.7G, the peak currents of RC, CC and HQ enhanced independently as the concentrations of HQ, CC and RC increased from 1 μM to 1000 μM. This indicated a strong linear association between the concentration and the peak current. The above experimental results showed that RC, CC and HQ could be detected simultaneously by CA-GCE with high selectivity and sensitivity, and did not interfere with each other. Finally, the comparison of CA-GCE and other
(A) CVs of CA-GCE in PBS (0.1 M) with 100 µM RC, CC and HQ at varying pH values (pH = 4.6, 5.44, 6.18, 7, 7.82 and 8.82) (a–f); Calibration plots of pH vs oxidation peak (B) and peak potential (C) of RC, CC and HQ. Scan rates: 50 mV s–1
LIU Hong-Ying et al. / Chinese Journal of Analytical Chemistry, 2019, 47(9): e19113–e19120
Table 1
Comparison of different modified electrodes for simultaneous determination of RC, CC and HQ
Modified electrode material Graphene-like carbon nanosheets Graphene quantum dots Porous reduced graphene oxide MWCNTs-PDDA-GR AgNP/MWCNT Au-PdNF/rGO Fe/PC AuNP/ZnS/NiS@ZnS quantum dots PGCE Am-GCE CA-GCE
Linear range (µM)
Detection limit (µM)
HQ
CC
RC
HQ
CC
RC
0.1–30 4–600 5–90 0.5–400 2.5–260 1.6–440 0.1–120 0.5–400 10–300 5–260 1–300
0.5–50 6–400 5–120 0.5–400 20–260 2.5–160 1–120 0.1–300 10–300 5–260 10–300
\ \ 5‒90 \ \ 2–112 \ \ \ \ 5-200
0.02 0.4 0.08 0.02 0.16 0.5 0.014 0.024 3.57 0.2 0.46
0.05 0.75 0.18 0.018 0.2 0.85 0.033 0.017 3.99 0.2 0.23
\ \ 2.62 \ \ 0.67 \ \ \ \ 0.47
Reference [9] [12] [17] [19] [22] [23] [24] [26] [8] [35] This work
Fig.7 CVs of (A) RC, (B) CC and (C) HQ at concentration levels of 1, 5, 10, 20, 50, 100, 200, 300, 500 and 1000 µM in PBS solution (pH 7, 0.1 M). The concentration of CC and HQ, RC and HQ, RC and CC are 100 µM; Calibration plots of oxidation peak currents of (B) RC, (D) CC and (F) HQ vs. concentrations of RC, CC, and HQ, respectively. (G) CVs of RC, CC and HQ at concentration levels of 1, 5, 10, 20, 50, 100, 200, 300, 500 and 1000 µM in PBS solution (pH 7, 0.1 M). (H) Peak currents vs concentrations of RC, CC, and HQ, respectively. Scan rate: 50 mV s–1
LIU Hong-Ying et al. / Chinese Journal of Analytical Chemistry, 2019, 47(9): e19113–e19120
activation and materials modified GCE for simultaneous detection of isomers of dihydroxybenzene is listed in Table 1. The results disclosed that the CA-GCE displayed a good detection limit and satisfied the demands of practical application.
89.9%–106.8%, respectively. And the recoveries of HQ, CC and RS in river water samples ranged from 100.9% to 104.9%, 91.6% to 95.9% and 95.1% to 96.0%, respectively. These results indicated that CA-GCE method possessed good feasibility in detection of real samples.
3.6
4
Selectivity, repeatability and stability of the method
To evaluate the selectivity of CA-GCE, some possible interferants such as Na+, K+, Ca2+, Zn2+, Mg2+, Cu2+, Pb2+, H2O2, and o-cresol were examined by CV. As displayed in Fig.8, these substances did not inhibit the current signals of RC, CC and HQ, which indicated that CA-GCE possessed good anti-interference ability. To test the repeatability, the same electrode was used to simultaneously detect 100 μM RC, CC, and HQ for four times under the same experimental circumstances. The relative standard deviations of RC, CC and HQ were 0.09%, 0.57% and 2.20%, respectively, indicating good constancy of CAGCE. Furthermore, the CA-GCE stored at room temperature for 3 days was used for measuring the concentration of HQ, CC and RC to investigate the stability. It was found that the oxidation peak currents of HQ, CC and RC were 96.3%, 94.67%, and 92.72% of the original values respectively, indicating a good stability. 3.7
Conclusions
In this work, an electrochemical sensor based on ammoniated-PBS activated CA-GCE was developed and characterized by electrochemical impedance spectroscopy, etc. Furthermore, CA-GCE was employed for simultaneously detecting HQ, CC as well as RC with high selectivity and sensitivity. Under the optimal conditions, the linear ranges for simultaneous detection of RC, CC, and HQ were 5–200 μM, 10–300 μM, and 1–300 μM, and the limits of detection were 0.46, 0.23 and 0.47 μM, respectively. The CA_GCE also possessed good anti-interference ability and stability. Consequently, this method showed wide applications in the fields of environments and others.
Analysis of real water samples
To test the applicability, this method was used to determine concentrations of HQ, CC and RS in the tap water samples and Yueya river water samples in Hangzhou Dianzi University and standard addition test was also conducted. As shown in Table 2, the recoveries of HQ, CC and RS in tap water samples were 97.3%–97.7%, 83%–97.7%, and Table 2 Sample Lake water Tap water
Fig.8
Histograms of current signals in the presence of 3-fold concentrations of Na+, K+ Ca+, Mg2+, Zn2+, Cu2+, Pb2+, H2O2, and o-cresol
Simultaneous determination results of HQ, CC and RS in real samples
Added (μM)
Found (μM)
Recovery (%)
RSD (%, n=3)
HQ
CC
RC
HQ
CC
RC
HQ
CC
RC
HQ
CC
RC
80 280 80 280
80 280 80 280
50 150 50 150
80.74 293.80 78.13 272.50
73.28 268.42 66.40 275.28
48.01 142.60 53.39 134.90
100.9 104.9 97.7 97.3
91.6 95.9 83 98.3
96.0 95.1 106.8 89.9
0.9 0.9 6.0 7.9
0.1 0.5 3.5 5.1
2.5 4.1 5.6 5.6
References
[5]
Nagaraia P, Vasantha R A, Sunitha K R. Talanta, 2001, 55(6): 1039‒1046
[1]
Zhang D D, Peng Y, Qi H L, Gao Q, Zhang C. Sens. Actuators
[6]
B, 2006, 136(1): 113–121 [2]
Dong S Y, Zhang P H, Yang Z, Huang T L. J. Solid State
[7]
Electrochem., 2012, 16(12): 3861–3868 [3]
Li S J, Xing Y, Deng D H, Shi M M, Guan P P. J. Solid State Marrubini G, Calleri E, Coccini T, Castoldi A F, Manzo L. Chromatographia, 2005, 62(1-2): 25–31
Cui H, He C X, Zhao G W. J. Chromatogr. A, 1999, 855(1): 171–179
[8]
Electrochem., 2015, 19(3): 861–870 [4]
Mihaljica S, Radulovic D, Trbojevic J. Chromatographia, 2005, 61(1-2): 25–29
Zhang H, Li S, Zhang F H, Wang M X, Lin X C, Li H X. J. Solid State Electrochem., 2017, 21(3): 735–745
[9]
Jiang H M, Wang S Q, Deng W F, Zhang Y M, Tan Y M, Xie Q J, Ma M. Talanta, 2017, 164(1): 300–306
LIU Hong-Ying et al. / Chinese Journal of Analytical Chemistry, 2019, 47(9): e19113–e19120
[10] Liu L Y, Ma Z, Zhu X H, Alshahrani L A, Tie S, Nan J M. Microchim. Acta, 2016, 183(12): 3293–3301 [11] Goulart L A, Mascaro L H. Electrochim. Acta, 2016, 196(1): 48–55 [12] Wang W, Yang X, Gu Y X, Ding C F, Wan J. Ionics, 2015, 21(3): 885–893 [13] Wittig J R, Wittemer S, Veit M. J. Chromatogr. B, 2001, 761(1): 125–132 [14] Richtera L, Nguyen H V, Hynek D, Kudr J, Adam V. Analyst, 2016, 141(19): 5577–5585 [15] Zare H R, Eslami M, Namazian M. Electrochim. Acta, 2011, 56(5): 2160–2164 [16] Song D M, Xia J F, Zhang F F, Xiang W J, Wang Z H, Xia L,
[27] Ribeiro G H, Vilarinho L M, Ramos T D S, Bogado A L, Dinelli L R. Electrochim. Acta, 2015, 176(10): 394–401 [28] Vilian A T E, Chen S, Huang L, Ali M A, Al-Hemaid F M A. Electrochim. Acta, 2014, 125(10): 503–509 [29] Erogul S, Bas SZ, Ozmen M, Yildiz S. Electrochim. Acta, 2015, 186(20): 302–313 [30] Unnikrishnan B, Ru P L, Chen S M. Sens. Actuators B, 2012, 169(5): 235–242 [31] Hason S, Vetterl V, Jelen F, Fojta M. Electrochim. Acta, 2009, 54(6): 1864–1873 [32] Liu L, Cui H, An H, Zhai J P, Pan Y. Ionics, 2017, 23(6): 1517–1523 [33] Chiavazza E, Berto S, Giacomino A, Malandrino M, Barolo C,
Xia Y Z, Li Y H, Xia L H. Sens. Actuators B, 2015, 206(1):
Prenesti E, Vione D, Abollino O. Electrochim. Acta, 2016,
111–118
192(1): 139–147
[17] Zhang H S, Bo X J, Guo L P. Sens. Actuators B, 2015, 220(1): 919–926 [18] Ramin M A T, Ghadimi H, Ab Ghani S. Sens. Actuators B, 2013, 177: 612–619 [19] Song D M, Xia J F, Zhang F F, Bi S, Xiang W J, Wang Z H, Xia L, Xia Y Z, Li Y H, Xia L H. Sens. Actuators B, 2015, 206(1): 111–118 [20] Xiao L L, Yin J, Li Y C, Yuan Q H, Shen H J, Hu G Z, Gan W. Analyst, 2016, 141(19): 5555–5562 [21] Zhang Y L, Xiao S X, Xie J L, Yang Z M, Pang P F, Gao Y T. Sens. Actuators B, 2014, 204(1): 102–108 [22] Goulart L A, Gonçalves R, Correa A A, Pereira E C, Mascaro L H. Microchim. Acta, 2018, 185(1): 12 [23] Chen Y, Liu X Y, Zhang S, Yang L Q, Liu M L, Zhang Y Y, Yao S Z. Electrochim. Acta, 2017, 231(20): 677–685 [24] Huang W, Zhang T, Hu X Y, Wang Y, Wang J M. Microchim. Acta, 2018, 185(1): 37 [25] Huang J S, Zhang X P, Zhu L M,You T Y. Sens. Actuators B, 2016, 224(1): 568–576 [26] Wang Y, Qu J H, Li S L, Dong Y, Qu J Y. Microchim. Acta, 2015, 182(13-14): 2277–2283
[34] Xu Q, Guo R X, Wang C Y, Hu X Y. Talanta, 2007, 73(2): 262–268 [35] Wang X Y, Xi M, Guo M M, Sheng F, Xiao G, Wu S, Uchiyama S, Matsuura H. Analyst, 2016, 141(3): 1077–1082 [36] Devadas B, Rajkumar M, Chen S. Int. J. Electrochem. Soc., 2013, 8(4): 5241–5249 [37] Rafiq K, Mai H D, Kim J K, Woo J M, Moon B M, Park C H, Yoo H. Sens. Actuators B, 2017, 251(1): 472–480 [38] Watanabe H, Yamazaki H, Wang X, Uchiyama S. Electrochim. Acta, 2009, 54(4): 1362–1367 [39] Shi K, Shiu K K. Anal. Chem., 2002, 74(4): 879–885 [40] Kong Y, Chen X H, Yao C, Ma M J. Anal. Methods, 2011, 3(9): 2121–2126 [41] Xing Q Y, Pei W W, Xu R Q, Pei J. Organic Chemistry. Beijing: Higher Education Press, 2005: 374 [42] Anil K A, Kumara S B E, Ganesh P S, Shobha R T, Venkata R G. J. Electroanal. Chem., 2017, 799(15): 505–511 [43] Peng L, Ji X, Wan H Z, Ruan Y J, Xu K, Chen C, Miao L, Jiang J J. Electrochim. Acta, 2015, 182: 361–367 [44] Nematollahi D, Golabi S M. J. Electroanal. Chem., 1996, 405(1): 133–140
Cite this article as: Chinese J. Anal. Chem., 2019, 47(9): e19113–e19120
RESEARCH PAPER
Simultaneous Detection of Hydroquinone, Catechol and Resorcinol by an Electrochemical Sensor Based on Ammoniated-Phosphate Buffer Solution Activated Glassy Carbon Electrode LIU Hong-Ying1, ZHU Lang-Lang1, HUANG Zhi-Heng1, QIU Yu-Bing1, XU Han-Xiao1, WEN Jia-Jun1, XIONG Wei-Wei3, LI Li-Hua1,*, GU Chun-Chuan2,* 1
College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Hangzhou 310018, China Deparment of Clinical Laboratory, Hangzhou Cancer Hospital, Hangzhou 310002, China 3 School of Environmental & Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003, China 2
Abstract:
An electrochemical sensor was successfully fabricated by coupled ammoniated modification with PBS activation on glassy
carbon electrodes (CA-GCE) and characterized by electrochemical impedance spectra. The CA-GCE showed outstanding electrochemical performance, and was applied to simultaneous detection of resorcinol (RC), catechol (CC) and hydroquinone (HQ), which could be ascribed to new active sites by the introduction of amino and oxygen-containing groups and H-bonds formed between hydroxyl groups of RC, CC, and HQ with amine, hydroxyl and carboxyl groups of CA-GCE. The reaction kinetics of RC, CC, and HQ and their reaction on CA-GCE were studied. Experimental results showed that the electrochemical reaction was adsorption controlled. Under the optimal conditions, the linear detection ranges for RC, CC, and HQ were 5–200 μM, 10–300 μM, and 1–300 μM, respectively, with their detection limits of 0.47, 0.23 and 0.46 μM, respectively. Interference and repeatability was further investigated. This strategy opened a new horizon for qualitative and quantitative detection of dihydroxy benzene. Key Words:
Ammoniated; Phosphate buffer solution activation; Hydroquinone; Catechol; Resorcinol
1 Introduction Resorcinol (RC), catechol (CC) and hydroquinone (HQ) represent three isomers of dihydroxy benzene. They are commonly applied in the field of dye, pharmaceuticals, cosmetics, antioxidants, pesticides, and rubbers industries [1]. However, these compounds can harm human health and pollute the environment, and are thus regarded as the significant environmental contaminants by the U.S. Environmental Protection Agency[2,3]. So, it is very important to distinguish and detect concentrations of these organic
substances. Plenty of methods and techniques have been developed for detection and identification of these organics in recent years, including high-performance liquid chromatography (HPLC)[4], spectrophotometry[5], chromatography[6], chemiluminescence[7] and electrochemical method[8-12]. HPLC is widely applied due to its high efficiency and sensitivity[13], but is hindered by the prolonged testing and exorbitant costs. Spectrophotometric detection is based on the specific wavelength of the material, but it is difficult to distinguish isomers. Chemiluminescent method has high sensitivity and convenient operation, but is unable to distinguish isomers with
________________________ Received 6 July 2018; accepted 28 June 2019 *Corresponding author. Email: [email protected]; [email protected] This work was supported by the Science and Technology Program of Zhejiang Province of China (No. LGF18H200005), the National Natural Science Foundation of China (Nos. 21405029, 617310008), the Medical and Health Technology Development Program of Zhejiang Province (No. 2017KY533), and the Young and Middle-aged Academic Leaders of Zhejiang Province, China. Copyright © 2019, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences. Published by Elsevier Limited. All rights reserved. DOI: 10.1016/S1872-2040(19)61183-7
LIU Hong-Ying et al. / Chinese Journal of Analytical Chemistry, 2019, 47(9): e19113–e19120
similar chemical reaction conditions. The electrochemical methods have attracted more attentions in recent years due to its simplicity, convenience, low-cost maintenance, high selectivity, wide detection range and high sensitivity[14,15]. Until now, the fabrication of modified glassy carbon electrode (GCE) in the detection of dihydroxy benzene isomers used a variety of materials, such as carbon material[16‒22], bimetallic nanostructured materials[23], doping graphite materials[24,25], metal oxides and sulfides[26‒30] and so on. Although lower detection limits and wider detection ranges were obtained by the above electrodes, their complex operation and ease of peeling off when testing severely limited the stability and sensitivity[31]. Therefore, activated electrodes which can directly modify related groups on the surface of glassy carbon electrode have been developed[8,32‒36]. Ammonification[37,38], sulfuric acid activation[39], and phosphate buffer solutions (PBS) activation[8] were the three main forms. These methods greatly simplified the modifying process. In addition, some nitrogen-containing groups and oxygencontaining groups which modified on the surface of the electrode[40] can improve the efficiency of electron transfer in the electrode. So, it is vital for exploring new activating methods. In this work, a novel composite activation electrode (CA-GCE) was successfully developed, as shown in Fig.1. First, primary and secondary amino groups were introduced into the surfaces of GCE by dripping it in an ammonium carbamate solution and then assisting electrooxidation treatment. Then, the above aminated GCE was further activated by simple anodic and cathodic polarization in PBS to introduce some oxygen-containing groups. Subsequently, the CA-GCE featured electrochemical impedance spectra (EIS). The CA-GCE exhibited good electrochemical behavior towards the electro-oxidation of RC, CC, and HQ, which
Fig.1
could be ascribed to that the synergy effect between amine groups and oxygen-containing groups could expand the surface area of electrode and increase the efficiency of electron transfer. Based on this, a novel electrochemical biosensor was developed for determination of concentrations of RC, CC and HQ.
2 Experimental 2.1
Instruments and reagents
Electrochemical experiments were conducted on a CS100 electrochemical workstation (Wuhan CorrTest Instruments Co., Ltd., China) employing a standard three-electrode system with the GCE as working electrode (WE), a platinum electrode as counter electrode (CE), and an Ag/AgCl electrode as reference electrode (RE). HQ, CC and RC with analytical grade were obtained from the Macklin Co., Ltd. (Shanghai, China). Ammonium carbamate was from the Aladdin group in Shanghai, China. PBS with different pH values were prepared by mixing 0.1 M NaH2PO4 and K2HPO4 in different ratios. Each solution was formulated using deionized water. All chemicals used were of at least analytical grade. 2.2
Fabrication of CA-GCE
After being polished by 0.30 and 0.05 μm Al2O3 powder, the GCE was ultrasonically cleaned with anhydrous ethanol and deionized water for 8 min each. Then, the GCE was dried with N2 and placed in ammonium carbamate solution (0.1 M). Then, using the constant potential method, the electrode was
Schematic of fabrication of CA-GCE and detection of RC, CC and HQ
LIU Hong-Ying et al. / Chinese Journal of Analytical Chemistry, 2019, 47(9): e19113–e19120
polarized at +1.1 V for 20 min, –1.0 V for 15 min to obtain an ammoniated electrode (Am-GCE). Finally, Am-GCE was further activated in PBS solution (0.1 M, pH 7) via the constant potential method at +1.7 V anodic polarization for 20 min, and cathodic polarization at ‒1.0 V for 15 min to obtain CA-GCE. For comparison, Am-GCE and PBS activated electrode (PGCE) was prepared by the first and second step. 2.3
Characterization of modified electrodes
EIS were tested in 0.1 M KCl solution containing 20 mM K3Fe(CN)6/K4Fe(CN)6. 2.4
Detection of HQ, RC and CC in real samples
Tap water samples and the Yueya Lake water samples in Hangzhou Dianzi University were detected. Filter papers were used firstly to remove large particles. Then, various concentrations of HQ, RC and CC were spiked in the real water samples. Finally, CA-GCE was used to determine the concentrations of HQ, RC and CC and the recoveries were calculated.
3 3.1
Results and discussion Characterization of CA-GCE
EIS was explored to investigate the electrochemical behavior of electrodes. As shown in Fig.2A and Fig.2B, CA-GCE had the lowest electron transfer resistance, indicating a highest charge transfer rate. This confirmed that the composite activation process could efficiently accelerate electron transfer rate of electrochemical probe Fe[CN]63‒/4‒. It might be due to the synergy effect between diverse groups of modification layer. 3.2
Electrochemical behaviors of RC, CC and HQ on CA-GCE
The cyclic voltammetry responses of 100 μM RC, CC and HQ on modified electrodes PGCE, Am-GCE, CA-GCE and bare
Fig.2
GCE in PBS (pH 7, 0.1 M) were analyzed. As shown in Fig.3, two redox peak pairs and an oxidation peak obviously appeared on both activated GCEs. For CC, the redox peak potential difference (ΔEp) was approximately 20–25 mV, 25–30 mV and 15–20 mV for PGCE, Am-GCE and CA-GCE, respectively. For HQ, ΔEp was approximately 23–28 mV, 25–30 mV, 20–25 mV and 20–25 mV for PGCE, Am-GCE, CA-GCE and bare GCE, respectively, while no distinct oxidation peak was found for bare GCE. This indicated good reversibility for the above activated GCE. However, the peak current of HQ on CA-GCE was about 1.85 and 1.54 times as those on Am-GCE and PGCE. The peak current of CC at CA-GCE was about 1.29 and 1.23 times as those on at Am-GCE and PGCE. This indicated the sensitivities of both CC and HQ at the CA-GCE were better than those of Am-GCE and PGCE. In summary, the CA-GCE showed an outstanding electrochemical behavior, indicating a promising potential for simultaneously detecting RC, CC and HQ. For PGCE, after electrochemical treatment, hydroxyl and carboxyl groups were introduced to the surface of the electrode. These abundant carboxyl and hydroxyl groups could greatly increase the electrochemical activity of PGCE. For Am-GCE, some primary amino groups and other N-containing groups were introduced to the surface of electrode by electrochemical polarization methods[8]. The introduction of these N-containing groups greatly improved the electrochemical performance of the electrode. But for CA-GCE, it might be ascribed to some of following reasons. First, the introduction of amino and oxygen-containing groups could supply new active sites, and thus accelerated the electron transport rate. Second, H-bonds were formed between hydroxyl groups of RC, CC and HQ with amine, hydroxyl and carboxyl groups of CA-GCE. These H-bonds could promote electron transfer rates. Third, the electrostatic interaction between these carboxyl groups (negative) and amino groups (positive) could enhance their electron transfer efficiency. Furthermore, the redox process of RC, CC, and HQ was also studied. As shown in Fig.3, they come forward one after another in the sequence of HQ, CC and RC. We analyzed various causes of this phenomenon on the basis theory of organic chemistry[41]. It was well known that -OH was a strong ortho-para substituent and had two effects on the benzene
(A) Nyquist plots of CA-GCE, PGCE, Am-GCE, and GCE. Frequency range: 0.1–1.0 ×105 Hz; (B) The enlarged view of (A)
LIU Hong-Ying et al. / Chinese Journal of Analytical Chemistry, 2019, 47(9): e19113–e19120
Fig.3
Cyclic voltammograms (CVs) for simultaneous detection of 100 μM RC, CC and HQ on Am-GCE, PGCE, CA-GCE and GCE in PBS (pH 7, 0.1 M). Scan rates: 50 mV s–1
ring. On one hand, the electronegativity of oxygen was so large that it produced an electron-induced effect. This effect could lower the electron cloud density on the benzene ring. On the other hand, a conjugated system was generated by the formation of p-π conjugate system between the lone pair of oxygen in ‒OH with π bond of benzene. This system could increase the electron cloud density of benzene ring, particularly for the ortho-position and para-position. For these two effects, the latter took the dominant position. Back to this point, [M]2‒ generated by HQ and CC formed a more stable quinone structure via electron transfer. This quinone structure was a very stable 8-atom conjugate system that contained six carbon atoms and two oxygen atoms. Thus, RC was the most difficult species to oxidize because the π-conjugation of keys did not pass between meta positions. Additionally, the oxidization of HQ was simpler than the oxidization of CC. 3.3
Effect of scan rates
The kinetic processes of RC, CC and HQ on CA-GCE were examined by studying various effects of scan rates on potential and peak currents[42]. CVs of 100 μM RC, CC and HQ in PBS (pH 7, 0.1 M) on the CA-GCE at various scan rates are displayed in Fig.4. It could be seen that oxidation peak current increased regularly with an increasing sweep rate.
Fig.4
As shown in Fig.4B and Fig.4C, the peak current and scan rate showed a linear relationship in the range of 10–90 mV s–1, indicating a surface-controlled mechanism[43]. The regression equations were ipa (μA) = (1.76 ± 0.09) + (0.15 ± 0.005)v (mV s‒1) for HQ, ipa (μA) = (1.30 ± 0.08) + (0.08 ± 0.002)v (mV s‒1) for CC, and ipa (μA) = (2.78 ± 0.06) + (0.06 ± 0.003)v (mV s‒1) for RC, with R2 of 0.993, 0.995 and 0.988, respectively. Furthermore, the peak current and the square root of the scan rate showed a linear relationship at 100–1000 mV s–1, revealing a diffusion-controlled mechanism[43]. The regression equations were ipa (μA) = (–4.55 ± 0.67) + (64.21 ± 1.68)v1/2 (V s‒1) for HQ, ipa (μA) = (–7.47 ± 0.32) + (53.32 ± 0.54)v1/2 (V s‒1) for CC, and ipa (μA) = (–7.27 ± 0.75) + (46.85 ± 1.62)v1/2 (V s‒1) for RC, with R2 of 0.993, 0.999 and 0.988, respectively. These variations demonstrated that CA-GCE had faster charge-transfer kinetics. In addition, it could be observed that there was a positive shift in the oxidation peaks potential and a negative shift in the reduction peaks potential of RC, CC, and HQ. Furthermore, the electrochemical redox reaction of CC on the CA-GCE (Fig.5) was explained according to ECEC mechanism[44]. The CC (I) could be oxidized to o-quinone (II), which was formed via rapid electron transfer (E1). Later, o-quinone (II) was followed by a 1,4-nucleophilic addition of primary ammonia on the CA-GCE to the quinone, producing the adduct (III) (C). Then the adduct (III) was oxidized to form quinonoids (IV) by electron transfer (E2). Finally, IV transformed to 3,4-diaminocatechol (V) by a 1,4-nucleophilic addition just like C above. Thus, the above reaction followed the ECEC mechanism proposed in Fig.5. With the generation of chemical reaction, the number of electron transfers in the redox process of CC increased from 2 to 4. The above results proved that the electrochemical reactions of CC on CA-GCE were controlled by the adsorption process, and two protons and two electrons attended the electrochemical oxidation. 3.4
Effect of pH value
It is generally believed that there is relationship between electrocatalytic properties of RC, CC, and HQ at CA-GCE and
(A) CVs of CA-GCE in PBS (pH 7.0, 0.1 M) containing 100 µM RC, CC and HQ at the scan rate of 10, 15, 20, 30, 50, 70, 90, 100, 150, 200, 250, 300, 350, 400, 500, 600, 700, 800 and 1000 mV s–1 (a‒t); Calibration plots of oxidation peak current for RC, CC and HQ vs scan rate at 0–90 mV s–1 (B) and 100–1000 mV s–1 (C), respectively
LIU Hong-Ying et al. / Chinese Journal of Analytical Chemistry, 2019, 47(9): e19113–e19120
Fig.5
Diagram of ECEC mechanism
pH. Furthermore, the concentration of H+ will affect the adsorption capacity of RC, CC and HQ[29]. Therefore, the effects of pH on both peak current and potential of RC, CC and HQ on CA-GCE were studied. Figure 6 shows CVs of CA-GCE in PBS (0.1 M) containing 100 µM RC, CC and HQ at various pH levels and their calibration plots. As shown in Fig.6B, the oxidation peak current of HQ and CC increased gradually as pH increased and leveled off at pH 6.18 and 7.00, respectively. However, the oxidation peak current of RC gradually decreased while pH was mounting. It might be ascribed to the fact that the electrooxidation reaction was difficult to occur at higher pH levels due to the shortage of protons. In summary, pH 7.00 was selected in the next experiments. Further studies about the connection between the oxidation peak potentials of HQ, CC and RC and pH were carried out. As shown in Fig.6C, there was a solid linear relationship between the oxidation peak potentials of HQ and CC as well as RC and pH. The regression equations were Epa (V) = (0.46 ± 0.011) – (0.049 ± 0.0017) pH for RC, Epa (V) = (0.61 ± 0.038) – (0.056 ± 0.005) pH for CC, and Epa (V) = (1.05 ± 0.015) – (0.061 ±0.0025) pH for HQ, with R2 of 0.994, 0.960 and 0.992 respectively. The slope of the above equations was nearly 59 mV/pH which was obtained from the equation ΔE/ΔpH = 2.303mRT/nF (m and n are the number of protons and electrons, respectively). It showed that two protons and two electrons process was involved in the electrochemical oxidation of HQ, CC and RC on CA-GCE[29].
Fig.6
3.5
Simultaneously detection of RC, CC and HQ
CV was employed to simultaneously detect RC, CC and HQ by CA-GCE with the scan rate of 50 mV s–1 in PBS (pH 7, 0.1 M). First, the concentrations of RC, CC or HQ were increased from 1 to 1000 µM while CC and HQ, RC and HQ, RC and CC two were kept at 100 µM. Then, the CV curves were drawn and the relationship between the concentration and peak current was examined. As shown in Fig.7A‒Fig.7F, there was a good linear relationship between the peak current and the concentration of RC, CC, or HQ. The regression equations were Ipa (μA) = (6.51 ± 0.18) + (0.059 ± 0.0035)CRC (μM), Ipa (μA) = (10.96 ± 0.46) + (0.066 ± 0.003)CCC (μM) and Ipa (μA) = (13.91 ± 0.15) + (0.046 ± 0.0016)CHQ (μM), with R2 of 0.983, 0.990 and 0.991, respectively. The limits of detection of RC, CC and HQ were 0.47, 0.23 and 0.46 μM (S/N = 3), respectively. Subsequently, the simultaneous detection of RC, CC and HQ was exploited through recording CV of CA-GCE by varying the concentrations of RC, CC and HQ. As shown in Fig.7G, the peak currents of RC, CC and HQ enhanced independently as the concentrations of HQ, CC and RC increased from 1 μM to 1000 μM. This indicated a strong linear association between the concentration and the peak current. The above experimental results showed that RC, CC and HQ could be detected simultaneously by CA-GCE with high selectivity and sensitivity, and did not interfere with each other. Finally, the comparison of CA-GCE and other
(A) CVs of CA-GCE in PBS (0.1 M) with 100 µM RC, CC and HQ at varying pH values (pH = 4.6, 5.44, 6.18, 7, 7.82 and 8.82) (a–f); Calibration plots of pH vs oxidation peak (B) and peak potential (C) of RC, CC and HQ. Scan rates: 50 mV s–1
LIU Hong-Ying et al. / Chinese Journal of Analytical Chemistry, 2019, 47(9): e19113–e19120
Table 1
Comparison of different modified electrodes for simultaneous determination of RC, CC and HQ
Modified electrode material Graphene-like carbon nanosheets Graphene quantum dots Porous reduced graphene oxide MWCNTs-PDDA-GR AgNP/MWCNT Au-PdNF/rGO Fe/PC AuNP/ZnS/NiS@ZnS quantum dots PGCE Am-GCE CA-GCE
Linear range (µM)
Detection limit (µM)
HQ
CC
RC
HQ
CC
RC
0.1–30 4–600 5–90 0.5–400 2.5–260 1.6–440 0.1–120 0.5–400 10–300 5–260 1–300
0.5–50 6–400 5–120 0.5–400 20–260 2.5–160 1–120 0.1–300 10–300 5–260 10–300
\ \ 5‒90 \ \ 2–112 \ \ \ \ 5-200
0.02 0.4 0.08 0.02 0.16 0.5 0.014 0.024 3.57 0.2 0.46
0.05 0.75 0.18 0.018 0.2 0.85 0.033 0.017 3.99 0.2 0.23
\ \ 2.62 \ \ 0.67 \ \ \ \ 0.47
Reference [9] [12] [17] [19] [22] [23] [24] [26] [8] [35] This work
Fig.7 CVs of (A) RC, (B) CC and (C) HQ at concentration levels of 1, 5, 10, 20, 50, 100, 200, 300, 500 and 1000 µM in PBS solution (pH 7, 0.1 M). The concentration of CC and HQ, RC and HQ, RC and CC are 100 µM; Calibration plots of oxidation peak currents of (B) RC, (D) CC and (F) HQ vs. concentrations of RC, CC, and HQ, respectively. (G) CVs of RC, CC and HQ at concentration levels of 1, 5, 10, 20, 50, 100, 200, 300, 500 and 1000 µM in PBS solution (pH 7, 0.1 M). (H) Peak currents vs concentrations of RC, CC, and HQ, respectively. Scan rate: 50 mV s–1
LIU Hong-Ying et al. / Chinese Journal of Analytical Chemistry, 2019, 47(9): e19113–e19120
activation and materials modified GCE for simultaneous detection of isomers of dihydroxybenzene is listed in Table 1. The results disclosed that the CA-GCE displayed a good detection limit and satisfied the demands of practical application.
89.9%–106.8%, respectively. And the recoveries of HQ, CC and RS in river water samples ranged from 100.9% to 104.9%, 91.6% to 95.9% and 95.1% to 96.0%, respectively. These results indicated that CA-GCE method possessed good feasibility in detection of real samples.
3.6
4
Selectivity, repeatability and stability of the method
To evaluate the selectivity of CA-GCE, some possible interferants such as Na+, K+, Ca2+, Zn2+, Mg2+, Cu2+, Pb2+, H2O2, and o-cresol were examined by CV. As displayed in Fig.8, these substances did not inhibit the current signals of RC, CC and HQ, which indicated that CA-GCE possessed good anti-interference ability. To test the repeatability, the same electrode was used to simultaneously detect 100 μM RC, CC, and HQ for four times under the same experimental circumstances. The relative standard deviations of RC, CC and HQ were 0.09%, 0.57% and 2.20%, respectively, indicating good constancy of CAGCE. Furthermore, the CA-GCE stored at room temperature for 3 days was used for measuring the concentration of HQ, CC and RC to investigate the stability. It was found that the oxidation peak currents of HQ, CC and RC were 96.3%, 94.67%, and 92.72% of the original values respectively, indicating a good stability. 3.7
Conclusions
In this work, an electrochemical sensor based on ammoniated-PBS activated CA-GCE was developed and characterized by electrochemical impedance spectroscopy, etc. Furthermore, CA-GCE was employed for simultaneously detecting HQ, CC as well as RC with high selectivity and sensitivity. Under the optimal conditions, the linear ranges for simultaneous detection of RC, CC, and HQ were 5–200 μM, 10–300 μM, and 1–300 μM, and the limits of detection were 0.46, 0.23 and 0.47 μM, respectively. The CA_GCE also possessed good anti-interference ability and stability. Consequently, this method showed wide applications in the fields of environments and others.
Analysis of real water samples
To test the applicability, this method was used to determine concentrations of HQ, CC and RS in the tap water samples and Yueya river water samples in Hangzhou Dianzi University and standard addition test was also conducted. As shown in Table 2, the recoveries of HQ, CC and RS in tap water samples were 97.3%–97.7%, 83%–97.7%, and Table 2 Sample Lake water Tap water
Fig.8
Histograms of current signals in the presence of 3-fold concentrations of Na+, K+ Ca+, Mg2+, Zn2+, Cu2+, Pb2+, H2O2, and o-cresol
Simultaneous determination results of HQ, CC and RS in real samples
Added (μM)
Found (μM)
Recovery (%)
RSD (%, n=3)
HQ
CC
RC
HQ
CC
RC
HQ
CC
RC
HQ
CC
RC
80 280 80 280
80 280 80 280
50 150 50 150
80.74 293.80 78.13 272.50
73.28 268.42 66.40 275.28
48.01 142.60 53.39 134.90
100.9 104.9 97.7 97.3
91.6 95.9 83 98.3
96.0 95.1 106.8 89.9
0.9 0.9 6.0 7.9
0.1 0.5 3.5 5.1
2.5 4.1 5.6 5.6
References
[5]
Nagaraia P, Vasantha R A, Sunitha K R. Talanta, 2001, 55(6): 1039‒1046
[1]
Zhang D D, Peng Y, Qi H L, Gao Q, Zhang C. Sens. Actuators
[6]
B, 2006, 136(1): 113–121 [2]
Dong S Y, Zhang P H, Yang Z, Huang T L. J. Solid State
[7]
Electrochem., 2012, 16(12): 3861–3868 [3]
Li S J, Xing Y, Deng D H, Shi M M, Guan P P. J. Solid State Marrubini G, Calleri E, Coccini T, Castoldi A F, Manzo L. Chromatographia, 2005, 62(1-2): 25–31
Cui H, He C X, Zhao G W. J. Chromatogr. A, 1999, 855(1): 171–179
[8]
Electrochem., 2015, 19(3): 861–870 [4]
Mihaljica S, Radulovic D, Trbojevic J. Chromatographia, 2005, 61(1-2): 25–29
Zhang H, Li S, Zhang F H, Wang M X, Lin X C, Li H X. J. Solid State Electrochem., 2017, 21(3): 735–745
[9]
Jiang H M, Wang S Q, Deng W F, Zhang Y M, Tan Y M, Xie Q J, Ma M. Talanta, 2017, 164(1): 300–306
LIU Hong-Ying et al. / Chinese Journal of Analytical Chemistry, 2019, 47(9): e19113–e19120
[10] Liu L Y, Ma Z, Zhu X H, Alshahrani L A, Tie S, Nan J M. Microchim. Acta, 2016, 183(12): 3293–3301 [11] Goulart L A, Mascaro L H. Electrochim. Acta, 2016, 196(1): 48–55 [12] Wang W, Yang X, Gu Y X, Ding C F, Wan J. Ionics, 2015, 21(3): 885–893 [13] Wittig J R, Wittemer S, Veit M. J. Chromatogr. B, 2001, 761(1): 125–132 [14] Richtera L, Nguyen H V, Hynek D, Kudr J, Adam V. Analyst, 2016, 141(19): 5577–5585 [15] Zare H R, Eslami M, Namazian M. Electrochim. Acta, 2011, 56(5): 2160–2164 [16] Song D M, Xia J F, Zhang F F, Xiang W J, Wang Z H, Xia L,
[27] Ribeiro G H, Vilarinho L M, Ramos T D S, Bogado A L, Dinelli L R. Electrochim. Acta, 2015, 176(10): 394–401 [28] Vilian A T E, Chen S, Huang L, Ali M A, Al-Hemaid F M A. Electrochim. Acta, 2014, 125(10): 503–509 [29] Erogul S, Bas SZ, Ozmen M, Yildiz S. Electrochim. Acta, 2015, 186(20): 302–313 [30] Unnikrishnan B, Ru P L, Chen S M. Sens. Actuators B, 2012, 169(5): 235–242 [31] Hason S, Vetterl V, Jelen F, Fojta M. Electrochim. Acta, 2009, 54(6): 1864–1873 [32] Liu L, Cui H, An H, Zhai J P, Pan Y. Ionics, 2017, 23(6): 1517–1523 [33] Chiavazza E, Berto S, Giacomino A, Malandrino M, Barolo C,
Xia Y Z, Li Y H, Xia L H. Sens. Actuators B, 2015, 206(1):
Prenesti E, Vione D, Abollino O. Electrochim. Acta, 2016,
111–118
192(1): 139–147
[17] Zhang H S, Bo X J, Guo L P. Sens. Actuators B, 2015, 220(1): 919–926 [18] Ramin M A T, Ghadimi H, Ab Ghani S. Sens. Actuators B, 2013, 177: 612–619 [19] Song D M, Xia J F, Zhang F F, Bi S, Xiang W J, Wang Z H, Xia L, Xia Y Z, Li Y H, Xia L H. Sens. Actuators B, 2015, 206(1): 111–118 [20] Xiao L L, Yin J, Li Y C, Yuan Q H, Shen H J, Hu G Z, Gan W. Analyst, 2016, 141(19): 5555–5562 [21] Zhang Y L, Xiao S X, Xie J L, Yang Z M, Pang P F, Gao Y T. Sens. Actuators B, 2014, 204(1): 102–108 [22] Goulart L A, Gonçalves R, Correa A A, Pereira E C, Mascaro L H. Microchim. Acta, 2018, 185(1): 12 [23] Chen Y, Liu X Y, Zhang S, Yang L Q, Liu M L, Zhang Y Y, Yao S Z. Electrochim. Acta, 2017, 231(20): 677–685 [24] Huang W, Zhang T, Hu X Y, Wang Y, Wang J M. Microchim. Acta, 2018, 185(1): 37 [25] Huang J S, Zhang X P, Zhu L M,You T Y. Sens. Actuators B, 2016, 224(1): 568–576 [26] Wang Y, Qu J H, Li S L, Dong Y, Qu J Y. Microchim. Acta, 2015, 182(13-14): 2277–2283
[34] Xu Q, Guo R X, Wang C Y, Hu X Y. Talanta, 2007, 73(2): 262–268 [35] Wang X Y, Xi M, Guo M M, Sheng F, Xiao G, Wu S, Uchiyama S, Matsuura H. Analyst, 2016, 141(3): 1077–1082 [36] Devadas B, Rajkumar M, Chen S. Int. J. Electrochem. Soc., 2013, 8(4): 5241–5249 [37] Rafiq K, Mai H D, Kim J K, Woo J M, Moon B M, Park C H, Yoo H. Sens. Actuators B, 2017, 251(1): 472–480 [38] Watanabe H, Yamazaki H, Wang X, Uchiyama S. Electrochim. Acta, 2009, 54(4): 1362–1367 [39] Shi K, Shiu K K. Anal. Chem., 2002, 74(4): 879–885 [40] Kong Y, Chen X H, Yao C, Ma M J. Anal. Methods, 2011, 3(9): 2121–2126 [41] Xing Q Y, Pei W W, Xu R Q, Pei J. Organic Chemistry. Beijing: Higher Education Press, 2005: 374 [42] Anil K A, Kumara S B E, Ganesh P S, Shobha R T, Venkata R G. J. Electroanal. Chem., 2017, 799(15): 505–511 [43] Peng L, Ji X, Wan H Z, Ruan Y J, Xu K, Chen C, Miao L, Jiang J J. Electrochim. Acta, 2015, 182: 361–367 [44] Nematollahi D, Golabi S M. J. Electroanal. Chem., 1996, 405(1): 133–140