Electrochemical behavior of azo food dye at nanoclay modified carbon electrode-a nanomolar determination

Accepted Manuscript Electrochemical behavior of azo food dye at nanoclay modified carbon electrode-a nanomolar determination Nagaraj P. Shetti, Deepti S. Nayak, Shweta J. Malode PII:

S0042-207X(18)30741-3

DOI:

10.1016/j.vacuum.2018.06.050

Reference:

VAC 8070

To appear in:

Vacuum

Received Date: 4 May 2018 Revised Date:

11 June 2018

Accepted Date: 19 June 2018

Please cite this article as: Shetti NP, Nayak DS, Malode SJ, Electrochemical behavior of azo food dye at nanoclay modified carbon electrode-a nanomolar determination, Vacuum (2018), doi: 10.1016/ j.vacuum.2018.06.050. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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Electrochemical behavior of azo food dye at nanoclay modified carbon electrode-a nanomolar determination

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Nagaraj P. Shetti*, Deepti S. Nayak, Shweta J. Malode Electrochemistry and Materials Group, Department of Chemistry, K. L. E. Institute of Technology, Gokul, Hubballi-580030, affiliated to Visvesvaraya Technological University, Karnataka, India. *

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Author for correspondence: Dr. Nagaraj P. Shetti, E-mail: [email protected], Tel.: +91 9611979743; Fax: 0836 – 2330688

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Abstract

In the current research, nanoclay particles modified carbon paste surface employed to determine sunset yellow (SY), a well-known azo food dye in nano level. With several astonishing characteristics such as strong adsorption, large surface area, and simple surface modification, the modifier grabbed some interest. The surface features of the modifier were premeditated by SEM

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(Scanning electronic microscopy) and XRD (X-ray diffraction) analysis. Unlike other techniques adopted for the electro oxidation study. A tremendous electrocatalytic behavior of the nanoclay modified electrode was explored towards the dye oxidation and a linear vibrant relationship in

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0.001 µM to 0.1 µM range with a LOD value of 0.2 nM. The main practical applicability of the fabricated sensor was explored by determining the dye in tablets, food materials including

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biological fluids. The low detection limit with good sensitivity, stability and specificity makes the modified sensor valuable for the entire analysis of SY. Keywords: Nanoclay; Electrochemical behavior; Sunset Yellow; Biomedical Analysis; Food Analysis

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Introduction In present scenario, the aptitude of electrochemical sensors was augmented from micro-molar to pico-molar determination of drug molecules as well as food additives by modulating the sensing

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surfaces [1-3]. High porosity of the materials, low electro-conductivity, great stability, vast surface area fascinated interest of electrochemists. Considering to the above points clay and its composites stood promising modifiers [4]. Generally clay particles are layered aluminosilicates

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with layered sheet type structure embedded over one another. These particles also called as phyllosilicates (sheet like silicates). Clay particles and its composite are chemically stable with

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controlled unique features. But now a day usage of nanomaterials of such type of minerals found advantageous.

Clay nanoparticles are actually subjugated via phyllosilicates and are totally alienated by common clay by various approaches like, stability, mechanical strength, large aspect ratio etc.

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and in last few years number of researches were assembled on multifarious applications of clay nano materials. Among them the key research provinces comprises of its synthesis, characterization, nanocomposites preparation and apply as solid ancestor for the advancement of Some of the appliance of nanoclay includes in the area of cosmetics [5],

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new materials.

medicine [6, 7], textile industry [8], food industry [9], environment protection [10] etc.

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In the present work we selected montmorillonite (MMT) nanoclay as surface modifier to determine a dye. This nanoclay belongs to smectite group which stood promising among the other members due to its chemical and physical properties. MMT nanoclay is having dioctahedral structure with 2:1 sheet linkage. From the literature review, found that MMT nanoclays are having the most competent potential for reinforcement which is ultimately associated with its vast surface area and aspect ratio [11]. Recently these are also utilized as

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electrode modifiers for drug determination and the results show its amazing selectivity, sensitivity, stability towards the analysis [12-16]. Carbon paste electrodes (CPEs) with reproducible values, less expensive, stability, and easy

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surface renewal, well-matched with various types of modifiers [15-18]. It shows extensive applications in electro analytical chemistry [17-19]. An azo dye, Sunset yellow (SY) give an appealing yellow shading to regular sustenance, for example, drinks, organic products,

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confections etc. [20]. The broad utilization of SY is between 0-50 µg/mL [21]. However, it causes some side effects, if it is inhaled above a certain limit (Fig. 1).

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Some analytical methods frequently reported on SY includes high-performance liquid chromatography [22-24] and spectrophotometry [25, 26]. Despite the fact that the above said techniques are largely acknowledged, but are tedious and expensive. For the on-site detection of SY, the electrochemical strategy has been considered as the best contender. In this manner, the

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construction of the sensor is a significant stride in the determination of SY. Reported works on SY includes some electrochemical methods [27-33], and also by expanded graphite paste electrode [34], MWCNTs and gold nanoparticles modified GCE [35], poly (L-cysteine) modified

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GCE [36], polyallylamine modified electrode [37], boron doped diamond electrode [38], graphene oxide and MWCNTs nanocomposite modified electrode [39] and Cu-BTC modified

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sensor [40], montmorillonite modified electrode [41], an electrode modified with molecularly imprinted polymers on functionalized MWCNTs [42], had been exploited to the determination of SY. Subsequently, there is still a requirement of a clear and an inexpensive sensor for SY detection with simple surface renewability, more remarkable long-standing steadiness, high affectability, and accuracy.

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Based on literature survey, not much reports on the application of MMT nanoclay as sensing substance for dye quantification. Hence, in the current study we utilized MMT nanoclay to modify the carbon paste surface (NC/CPE) and applied that to determine an azo dye, SY.

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Scanning electronic microscope (SEM) and X-ray diffraction (XRD) studies reveals surface characteristics. Nanomolar level determination of SY is shown by fabricated NC/CPE and

sample.

Experimental Instrumentation and chemicals

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“Here Figure 1.”

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applied them for the identification in tablets, food samples, as well as in spiked human urine

The clay nanoparticles structure dimension were subjected to powder XRD (Phillips PW1729, Cu kα), and SEM (Jeol JSM-6360). With the help of CHI Company, electrochemical analyzer

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D630, USA, voltammetric measurements were carried out. The cell was integrated by three electrodes, proposed sensor as NC-CPE, counter sensor as platinum wire, and reference electrode as Ag/AgCl (3.0 M KCl). Renewal of working sensor was completed by means of polishing and

performed.

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then washed using water. By utilizing pH meter (Elico Ltd., India) the pH measurements were

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Nano clay with particle size of ≤ 20µm, the dye SY and other chemical reagents were purchased from Sigma Aldrich. For entire study double distilled water was used. The SY (0.01 mM) solution prepared in double distilled water. Different pH supporting electrolyte phosphate buffer saline (PBS) having 3.0 to 11.2 was primed with a 0.2 M concentration [43, 44].

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Preparation of modified electrode Merging of graphite powder with paraffin oil homogeneously in 7:3 ratio done to fabricate carbon paste. This paste was crammed firmly in a polytetrafluoroethylene tube (PTFE) cavity,

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and polished. After each measurement, the used paste was discarded and packed new paste. Similarly, the NC modified paste electrode was prepared by adding clay nanoparticles in an

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apposite amount to the blended mixture during the paste preparation. Procedures for pharmaceutical preparations

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Finelyground powder of SY coated tablet was dissolved 100 ml volumetric flask and sonicated for ten minutes. The resulting solution was studied for testing effect of excipients with clinical samples by standard addition method and accurateness of the proposed sensing technique was analyzed. The recovery study used to test the exactitude of the method.

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Procedures for SY analysis in food samples

In commercially available soft drinks, this method was also applied to detect SY. The real samples were prepared in pH buffer by using commercially available soft drinks (Maaza; The

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Coca-cola Company, Frooty; Parle Agro India Pvt. Ltd.). The SWVs were recorded in optimized conditions and by standard addition method the content of the dye was determined in food

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samples.

Analysis of urine samples

At room temperature, the collected human urine samples were centrifuged (4383 G) and then using 6.0 pH, spiked urine test solutions were prepared. The recovery studies were carried out using SWV technique.

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Results and discussion Determination of active surface area Randles-Sevcik equation used to determine active exposed area in the vicinity of proposed

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sensor. To carry out this KCl (0.1 M) and K3Fe(CN)6 (1.0 mM) were used. By varying scan rates at 298 K LSV technique was adopted [47]. The area found to be 0.042 cm2 unmodified CPE while modified CPE showed almost two times greater area i.e., 0.086 cm2.

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Ip = (2.69 x 105) n3/2 A D01/2 ν1/2 C0*

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Nano clay particles characterization

(1)

The modifier particles surface features lead a very significant component in electrochemical sensor working mechanism. Thus the characterization study was done by using SEM and X-ray diffraction (XRD) analysis.

SEM image (Fig. 2A) of clay nanoparticles portrays the characteristic “cornflake” type sheets

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which arranged in random manner. For sensor area enrichment this kind of assembly was very favorable. Better the surface area, more dye particles will be loaded on the electrode surface. The

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XRD image (Fig. 2B) shows the diffraction peak at 2θ = 20.05° with high intensity. “Here Figure 2.”

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Influence of pre-concentration time Pre-concentration time effect was studied in the range of 0-100 seconds which helps in electro analytical chemistry to gather analyte molecules near electrode active surface to enhance the sensitivity (Fig. 3). Highest current was observed at 60 seconds; hence further steps were carried out incorporating the same time as accumulation time. “Here Figure 3.”

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Effect of nanoclay concentration on SY behaviour Voltammogram of SY was recorded by changing the weight of modifier during the sensor

further studies did maintaining the ratio constant. Electro-oxidation performance of SY

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preparation. From the observation 4.0% NC amount was found be most advantageous. Hence

LSVs using CPE and NC-CPE in absence and presence of 0.01 mM SY in pH 6.0 PBS at 50

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mVs−1 were obtained (Fig. 4). It was observed that a less peak currents obtained at anodic

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potential (Ep) = 0.828 V with peak current -2.616 µA at CPE, while at NC-CPE, a fine oxidation peak with Ep= 0.796 V and peak current of -6.585 µA was evidenced. Modifier NC increases the peak currents by making the electron transfer fast. The surface characteristics such as strong adsorptive competence, stability and large surface area [11] were responsible for such electrochemical behavior. In addition there might be some interaction between nanoclay particles

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and SY molecules electro statically, which lead to high consignment of dye on NC-CPE. “Here Figure 4.”

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Effect of supporting electrolyte

Electrocatalytic character of NC and SY in different pH PBS was studied using 0.01 mM analyte

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by LSV method, from 3.0-11.2 pH series of ionic strength 0.2 M (Fig. 5). Involvement of protons was evidenced since there was negative shift of potential values of peak [46]. At 6.0 pH, uppermost current of the peak was perceived. Hence, additional studies carried out using pH 6.0 (Fig. 5A). From Ep versus pH plot (Fig. 5B), linear equation attained is as follows; Ep= -0.030 pH + 0.928; R2 = 0.993. The slope value denotes same number of protons and electrons are transferred [47]. “Here Figure 5.” 7

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Influence of scan rate The electrode reaction mechanism and other details can be obtained from scan rate variation parameter. LSVs of SY were verified varying scan rates in pH 6.0 (Fig. 6). The vlues of peak

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current (Ip) increased with increased scan rate (υ) increase (Fig. 6A). A linear correlation between the υ1/2 and Ip demonstrates that the process is controlled by diffusion. Ip (µA) = 35.34 υ1/2 – 1.291; R2 = 0.995

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The log Ip vs. log υ plot results in a straight line gives a slope of 0.618 (Fig. 6B). This is close to the diffusion-controlled process theoretical value of 0.5 [48] leads equation: log Ip (µA) = 0.618

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log υ + 1.613; R2 = 0.995. Linear relation was observed between Ep and log ν (Fig. 6C) with the regression equation: Ep (V) = 0.010 log υ + 0.716; R2 = 0.970. According to Laviron’s theory, relationship between Ep and υ is given by [49].

RTk0

2.303 R T Ep =

E0 +

log

αnF

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αnF

2.303 R T

+

αnF

logυ

(2)

According to Bard and Faulkner [50], α is calculated as,

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∆Εp= Ep - Ep/2=

47.7 αn

mV

(3)

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The value of α found to be 0.55. The rate constant was calculated to be 2.13 x 103 s-1 and one is the number of electron from Ep versus log υ intercept. “Here Figure 6.”

Oxidation mechanism of SY The participation of equivalent quantity of electrons and protons was concerned in the SY oxidation process, which was determined from LSV data at different pH values and also by scan rate variation study. Similar oxidation behavior reported for some compounds like hydroxyl8

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substituted azo dyes also [51]. Based upon the results electrochemical reaction of SY was anticipated in the following Fig. 7.

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“Here Figure 7.” Analytical applications Concentration study and detection limit

Fig. 8 obtained by recording SWVs of SY at modified sensor varying the concentration range

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from 0.001 µM to 0.1 µM in pH 6.0 with an equation: Ip (µA) = 9.091 C (µM) + 1.225; R2 =

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0.979. Limit of detection and quantification data (LOD and LOQ) for SY were estimated by the developed sensitive SWV method. Value of 0.2 nM LOD and 0.9 nM LOQ was calculated employing equations 3Sb/M and 10Sb/M (S=blank standard deviation, M= slope) [52]. The proposed work results into an effective, extremely sensitive technique with low detection values for SY compared to reported sensors performances (Table 1).

Hence current work is

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recommended to show potential for detection of SY. “Here Figure 8.”

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“Here Table 1.”

Effect of excipients

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In presence of some metabolites interfering agents, SWVs of were recorded. The SWVs recorded were compared to the standard voltammogram obtained in absence of SY and the result showed that the potential difference with the drug do not exceed ±5%. Hence SY reactions at the sensing base, does not get affected by the subsistence of any excipients (Figure 9). Thus, the modified working sensor can be competently exploited for SY finding. “Here Figure 9.”

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Tablet and food analysis

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Solutions were prepared according to the procedure 2.3. SWVs were recorded by an addition of a recognized measure of dye to pre-analyzed specimens. The recovery lied in the range from 95.0 98.60% (Table 2). The estimated method was suitable for food sample analysis. The available

“Here Table 2.”

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SY detection in urine samples

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fruit juices in market were taken for the studies. The obtained results were included in Table 2.

The SWV voltammetric method developed for SY quantification was utilized for urine samples. The recovery of SY in urine samples was analyzed by spiking urine sample with identified amount of SY. A quantitative analysis showed that peak currents increased with SY addition to the samples. Recovery studies were conceded and results are illustrated in Table 3, which are

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good for SY quantification in urine samples.

“Here Table 3.”

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NC-CPE Repeatability and Reproducibility

Adapted sensor repeatability was checked by storing the working sensor an air free pot, for ten to

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fifteen days. The sensors maintained 98.82% of its preliminary Ip with respect to 0.01mM of SY. This results in a very good stability of NC modified CPE. Intra-day reproducibility was checked keeping constant temperature taking a fixed amount of dye (0.01 mM), five tiresome readings were documented. % RSD (relative standard deviation) of about 2.98% was noticeable for good reproducibility of the sensor for SY detection. Thus obtained results connote that the fabricated electrode is highly stable and reproducible in the determination of SY. 10

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Conclusion In this paper NC particles were introduced as efficient modifier to the CPE matrix for SY quantification. The morphology of clay nanoparticles were studied by XRD and SEM analysis.

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Compared to bare CPE the modified CPE shows enriched resolution, sensitivity and selectivity towards the analysis, due to the multifarious features of nanoclay. SY is electrochemically active in all the pH studied, but in pH 6.0 an accentuated peak was observed. The process was diffusion

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controlled and unequal number of electrons-protons transfer was observed. Compared to reported techniques, this study is very notable on account of utilized modifiers for working sensor and

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also because of its unique properties. Therefore, SY quantification and determination in food samples and human urine samples the current study is advantageous.

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Acknowledgements

Deepti S. Nayak, thanks the Department of Science and Technology, Government of India, New

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work.

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Delhi for the awarding Inspire Fellowship in Science and Technology to carry out the research

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48. Brown, E.R., Large, R.F., Weissberger, A., Rossiter, B.W., Physical methods of chemistry. New York: Wiley Interscience. Rochester; 1964.

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49. Laviron, E., General expression of the linear potential sweep voltammogram in the case of diffusion less electrochemical systems, J. Electroanal. Chem., 1979. 101: p. 19-28. 50. Bard, A.J., Faulkner, L.R., Electrochemical methods: fundamentals and applications. 2nd ed. New York: John Wiley and sons; 2004. 51. Sadler, J., Bard, A., The electrochemical reduction of aromatic azo compounds. J. Am. Chem. Soc., 1968. 90: p. 1979-1989. 52. Shetti, N.P., Malode, S.J., Nandibewoor, S.T., Electro-oxidation of captopril at a gold electrode and its determination in pharmaceuticals and human fluids, Anal. Methods, 2015. 7: p. 8673-8682. 16

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Figure captions Fig. 1. Chemical structure of Sunset yellow (SY). Fig. 2. Surface morphology study of nanoclay particles: (A) SEM image; (B) XRD pattern.

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Fig. 3. Variation of peak current for 0.01 mM SY with accumulation time.

Fig. 4. Voltammetric behavior of 0.01 mM SY in pH 6.0, phosphate buffer (I = 0.2 M); Scan rate = 0.05 Vs-1; Accumulation time = 60 s: (a) LSV of phosphate buffer of pH 6.0 at CPE;

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(a*) LSV of 0.01 mM SY at CPE; (b) LSV of phosphate buffer of pH 6.0 at nanoclay modified CPE; (b*) LSV of 0.01 mM SY at NC-CPE.

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Fig. 5. Linear sweep voltammograms obtained for 0.01 mM SY in buffer solution of different pH at NC-CPE; Scan rate = 0.05 Vs-1; Accumulation time = 60 s: (A) Variation of peak currents Ip / µA of SY with pH, (B) Influence of pH on the peak potential Ep / V of SY. Fig. 6. Linear sweep voltammograms of 0.01 mM SY in buffer solution of pH 6.0 (I = 0.2 M )

TE D

at NC-CPE with scan rate of : (1) blank; (2) 0.01; (3) 0.02; (4) 0.03; (5) 0.06; (6) 0.09; (7) 0.10 V s-1; (8) 0.12; (9) 0.15; (10) 0.2. (Accumulation time = 60 s). Fig. 7. Possible electrode reaction mechanism of Sunset yellow (SY).

EP

Fig. 8. Square wave voltammograms with increasing concentrations of SY in pH 6.0 at NC-CPE: (1) blank; (2) 0.001; (3) 0.006; (4) 0.01; (5) 0.03; (6) 0.06; (7) 0.1; (8) 0.18 µM

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(Accumulation time=60 s); Inset: Plot of concentration versus peak current Ip / µA.

Fig. 9. Influence of potential interferents on the voltammetric response of 0.01 mM SY.

17

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Table captions Table 1. Comparison of detection limits of SY by voltammetric methods using diverse working

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electrodes. Table 2. Analysis of SY in tablets and food samples by SWV and recovery studies at NC-CPE.

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EP

TE D

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Table 3. Application of SWV for the determination of SY in spiked human urine samples.

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Tables Table 1. Technique LOD (M) AdSVo 1.6 x 10-6 DPVp 1.1 x 10-8 DPV 3.0 x 10-8

AuNP/CPEc

[29]

GN/PTA/GCEd

DPV

0.5 x 10-7

MIP-rGO-ILe

DPV

4.0 x 10-9

CTAB-Gr-Pt/GCEf

DPV

4.2 x 10-9

[32]

AuNP/ RGO/GCEg

DPV

2.0 x 10-9

[33]

DPV

5.0 x 10-9

[34]

DPV

4.03 x 10-8

[35]

DPV

4.0 x 10-9

[36]

SWVq

3.5 x 10-6

[37]

DPV

13.1 x 10-9

[38]

LSVr

25.0 x 10-9

[39]

MIP/f-MWCNTsm/GCE

DPV

5.0 x 10-9

[42]

NC-CPEn

SWV

0.2 x 10-9

Present work

MWCNT/AuNPi Poly (L-cysteine)/ GCEj

BDDEk

EP

GO/MWCNTsl

TE D

Polyallylamine/ GCE

[30] [31]

SC

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EGPEh

Hanging mercury drop electrode; b Multiwalled carbon nanotube modified glassy carbon electrode;c Gold nanoparticles modified carbon paste electrode; dGraphene wrapped phosphotungustic acid modified glassy carbon electrode; e Molecular imprinted ionic liquid polymer-ionic liquid functionalized graphene composite film coated glassy carbon electrode; f Hexadecyltrimethyl ammonium bromide functionalized graphene supported platinum nanoparticles composite modified glassy carbon electrode; g Gold nanoparticles and reduced graphene oxide modified glassy carbon electrode; hExpanded graphite paste electrode; i Multiwalled carbon nanotube/gold nanoparticles modified electrode; j Glassy carbon electrode; k Boron doped diamond electrode; lGraphene oxide and multiwalled carbon nanotubes nanocomposite; m molecularly imprinted polymers on functionalized multi-walled carbon nanotubes; n nanoclay modified carbon paste electrode; o Adsorptive stripping voltammetry; p Differential pulse voltammetry; q Square wave voltammetry; r Linear sweep voltammetry.

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a

Reference [27] [28]

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Electrodes HMDEa MWCNT/ GCEb

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Table 2.

Sample

Declared (mol/L)

Detected(mol/L)*

Recovery (%)

Tablet sample 1

1.0 x 10-4

0.986 x 10-4

98.60

1.91

Tablet sample 2

0.5 x 10-4

0.475 x 10-4

95.00

1.98

Tablet sample 3

0.2 x 10-4

0.195 x 10-4

97.80

1.93

Fruit Juice 1

4.0 x 10-6

3.89 x 10-6

97.25

1.52

Fruit Juice 2

6.0 x 10-6

5.80 x 10-6

96.66

1.45

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EP

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SC

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TE D

*Average five readings

RSD(%)

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Table 3.

Urine samples

Spiked (10-4 M)

Detected (10-4 M)*

Recovery (%)

Sample 1

0.2

0.1993

99.6

1.82

Sample 2

0.5

0.4755

95.1

1.91

Sample 3

0.8

0.7693

96.1

1.89

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SC

AC C

EP

TE D

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*Average five readings

RSD (%)

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N

N

M AN U

O3S

SC

HO

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Figures

AC C

EP

TE D

Fig. 1. Chemical structure of Sunset yellow (SY).

SO3

M AN U

SC

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AC C

EP

TE D

Fig. 2. Surface morphology study of nanoclay particles: (A) SEM image; (B) XRD pattern.

TE D

M AN U

SC

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EP

Fig. 3. Variation of peak current for 0.01 mM SY with accumulation time.

EP

TE D

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SC

RI PT

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Fig. 4. Voltammetric behavior of 0.01 mM SY in pH 6.0, phosphate buffer (I = 0.2 M); Scan rate

AC C

= 0.05 Vs-1; Accumulation time = 60 s: (a) LSV of phosphate buffer of pH 6.0 at CPE; (a*) LSV of 0.01 mM SY at CPE; (b) LSV of phosphate buffer of pH 6.0 at nanoclay modified CPE; (b*) LSV of 0.01 mM SY at NC-CPE.

EP

TE D

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SC

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Fig. 5. Linear sweep voltammograms obtained for 0.01 mM SY in buffer solution of different pH

AC C

at NC-CPE; Scan rate = 0.05 Vs-1; Accumulation time = 60 s: (A) Variation of peak currents Ip / µA of SY with pH, (B) Influence of pH on the peak potential Ep / V of SY.

EP

TE D

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SC

RI PT

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Fig. 6. Linear sweep voltammograms of 0.01 mM SY in buffer solution of pH 6.0 (I = 0.2 M )

AC C

at NC-CPE with scan rate of : (1) blank; (2) 0.01; (3) 0.02; (4) 0.03; (5) 0.06; (6) 0.09; (7) 0.10 V s-1; (8) 0.12; (9) 0.15; (10) 0.2. (Accumulation time = 60 s).

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O

N

- H+

N

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SO3

O

N

O3S

N

TE D

O3S

N

O3S

EP

SO3

Fig. 7. Possible electrode reaction mechanism of Sunset yellow (SY).

AC C

N

SC

O3S

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HO

SO3

-eO

N

N

SO3

TE D

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SC

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EP

Fig. 8. Square wave voltammograms with increasing concentrations of SY in pH 6.0 at NC-CPE: (1) blank; (2) 0.001; (3) 0.006; (4) 0.01; (5) 0.03; (6) 0.06; (7) 0.1; (8) 0.18 µM (Accumulation

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time=60 s); Inset: Plot of concentration versus peak current Ip / µA.

EP

TE D

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SC

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Fig. 9. Influence of potential interferents on the voltammetric response of 0.01 mM SY.

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Highlights

Nanoclay particles modified carbon paste surface employed to determine sunset yellow

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•

(SY), a well-known azo food dye in nano level. •

The surface features of the modifier were premeditated by SEM and XRD analysis.

•

The main practical applicability of the fabricated sensor was explored by determining the

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The low detection limit with good sensitivity, stability and specificity makes the modified

EP

TE D

sensor valuable for the entire analysis of SY.

AC C

•

SC

dye in tablets, food materials including biological fluids.