scholarly journals An Electrocatalytic Screen-Printed Amperometric Sensor for the Selective Measurement of Thiamine (Vitamin B1) in Food Supplements

Biosensors ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 98 ◽  
Author(s):  
Amy Smart ◽  
Kelly L. Westmacott ◽  
Adrian Crew ◽  
Olena Doran ◽  
John P. Hart

An electrocatalytic screen-printed sensor has been investigated for the measurement of the biologically important biomolecule vitamin B1 (thiamine) for the first time in food supplements. Under basic conditions, the vitamin was converted to its electrochemically active thiolate anion species. It was shown that an electrocatalytic oxidation reaction occurred with the screen-printed carbon electrode containing the mediator cobalt phthalocyanine (CoPC-SPCE). This had the advantage of producing an analytical response current at an operating potential of 0 V vs. Ag/AgCl compared to +0.34 V obtained with plain SPCEs. This resulted in improved selectivity and limit of detection. Detailed studies on the underlying mechanism occurring with the sensor are reported in this paper. A linear response was obtained between 0.1 and 20 µg mL−1, which was suitable for the quantification of the vitamin in two commercial products containing vitamin B1. The mean recovery for a multivitamin tablet with a declared content of 5 mg was 101% (coefficient of variation (CV) of 9.6%). A multivitamin drink, which had a much lower concentration of vitamin B1 (0.22 mg/100 mL), gave a mean recovery of 93.3% (CV 7.2%). These results indicate that our sensor holds promise for quality control of food supplements and other food types.

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4324 ◽  
Author(s):  
Nurul Talib ◽  
Faridah Salam ◽  
Yusran Sulaiman

Clenbuterol (CLB) is an antibiotic and illegal growth promoter drug that has a long half-life and easily remains as residue and contaminates the animal-based food product that leads to various health problems. In this work, electrochemical immunosensor based on poly(3,4-ethylenedioxythiophene)/graphene oxide (PEDOT/GO) modified screen-printed carbon electrode (SPCE) for CLB detection was developed for antibiotic monitoring in a food product. The modification of SPCE with PEDOT/GO as a sensor platform was performed through electropolymerization, while the electrochemical assay was accomplished while using direct competitive format in which the free CLB and clenbuterol-horseradish peroxidase (CLB-HRP) in the solution will compete to form binding with the polyclonal anti-clenbuterol antibody (Ab) immobilized onto the modified electrode surface. A linear standard CLB calibration curve with R2 = 0.9619 and low limit of detection (0.196 ng mL−1) was reported. Analysis of milk samples indicated that this immunosensor was able to detect CLB in real samples and the results that were obtained were comparable with enzyme-linked immunosorbent assays (ELISA).


2020 ◽  
Vol 16 (5) ◽  
pp. 570-579
Author(s):  
Fuzi M. Fartas ◽  
Jaafar Abdullah ◽  
Nor A. Yusof ◽  
Yusran Sulaiman ◽  
Mohd I. Saiman ◽  
...  

Background: Bisphenol A (BPA) is considered one of the most common chemicals that could cause environmental endocrine disrupting. Therefore, there is an increasing demand for simple, rapid and sensitive methods for BPA detection that result from BPA leaching into foods and beverages from storage containers. Herein, a simple laccase electrochemical biosensor was developed for the determination of BPA based on Screen-Printed Carbon Electrode (SPCE) modified graphenegold/ chitosan. The synergic effect of graphene-gold/chitosan nanocomposite as electrode modifier greatly facilitates electron-transfer processes between the electrolyte and laccase enzyme, thus leads to a remarkably improved sensitivity for bisphenol A detection. Methods: In this study, laccase enzyme is immobilized onto the Screen-Printed Carbon Electrode (SPCE) modified Graphene-Decorated Gold Nanoparticles (Gr-AuNPs) with Chitosan (Chit). The surface structure of nanocomposite was studied using different techniques including Field Emission Scanning Microscopy (FESEM), TRANSMISSION Electron Microscopy (TEM), Raman spectroscopy and Energy Dispersive X-ray (EDX). Meanwhile, the electrochemical performances of the modified electrodes were studied using Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV). Results: The developed laccase biosensor offered excellent analytical performance for the detection of BPA with a sensitivity of 0.271 μA/μM and Limit of Detection (LOD) of 0.023 μM, respectively. Moreover, the constructed biosensor showed good reproducibility, selectivity and stability towards BPA. The sensor has been used to detect BPA in a different type of commercial plastic products as a real sample and satisfactory result was obtained when compared with the HPLC method. Conclusion: The proposed electrochemical laccase biosensor exhibits good result which is considered as a promising candidate for a simple, rapid and sensitive method especially in the resource- limited condition.


2019 ◽  
Vol 824 ◽  
pp. 182-189
Author(s):  
Chim Math ◽  
Wijitar Dungchai ◽  
Sudtida Pliankarom Thanasupsin

17α-methyltestosterone (MT) is a synthetic androgen. It is used widely for inducing an all-male population of Nile tilapia (Oreochromis niloticus). In this work, the detection of MT was conducted using screen-printed carbon electrodes (SPCE). These were a bare electrode, a bismuth modified electrode (Bi-SPCE) and an antimony modified electrode (Sb-SPCE). The successful electrode modification was confirmed by scanning electron microscopy. The electroanalytical performance of the SPCE modified electrodes for MT detection was examined by cyclic voltammetry. The highest active surface area of 1.073x10-4 cm2 was obtained on Sb-SPCE. This indicates that Sb-SPCE can enhance the sensitivity of MT detection better than the bare-SPCE and the Bi-SPCE. The Sb-SPCE showed a linear response for MT concentrations ranging from 2 to 8 mg.L-1. The sensitivity obtained from the slope of a calibration curve was -0.452 mA.mol-1.L-1 in a Britton-Robinson buffer pH 4.0 containing Sb 16 mg.L-1 with deposition potential and deposition time of 1 V and 90 seconds, respectively. A linear relationship between the square root of the scan rate and the peak current revealed that mass transfer of MT to the electrode was driven by a diffusion mechanism. The limit of detection was found to be 1 mg.L-1.


Al-Kimia ◽  
2018 ◽  
Vol 6 (2) ◽  
Author(s):  
Dian Siska Rahma Fatonah ◽  
Deden Saprudin ◽  
Dyah Iswantini ◽  
Novik Nurhidayat

Biosensor based on biofilm of L. plantarum has been successfully done for determination of uric acid in human urine compared with colorimetric enzymatic produced relative error of less than 5%. L. plantarum has uricase activity to react with uric acid, to maintain the stability of bacteria forming themselves into biofilms. Magnetite is known to increase sensitivity of the biosensor. The combination of magnetite-polyethylene glycol (Fe3O4-PEG) was used to modify the surface of Screen-Printed Carbon Electrode modified (SPCE) and the resulting modified electrode (biofilm/Fe3O4/PEG/SPCE) displayed good electrocatalytic activity to the oxidation of UA. The composition of biofilms with optical density 1, magnetite 100 mgmL-1 and PEG 3% v / v were able to increase the current up to 48% in 4mM of UA. The biosensor with an optimum composition produced good linearity with a concentration range, limit of detection, limit of quantitation, sensitivity, and repeatability were found to be 0.1 - 4.3 mM, 70 µM,  234 µM, 25.392 µA mM-1, 2.38%, respectively. This biosensor stable up to 49 days of measurement with the remaining activity was 90.70% and selective for interference compounds such as salt, urea, glucose, ascorbic acid. This method has a good stability, sensitivity, and potential application in clinical analysis. Keyword: biofilm, biosensor, L. plantarum, magnetite, uric acid.


2021 ◽  
Vol 24 (2) ◽  
pp. 43-50
Author(s):  
Wulan Tri Wahyuni ◽  
Rudi Heryanto ◽  
Eti Rohaeti ◽  
Achmad Fauzi ◽  
Budi Riza Putra

A screen-printed carbon electrode is a suitable electrode for electrochemical sensors due to its simplicity and portability. This study aimed to fabricate a screen-printed carbon electrode modified with poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (SPCE-PEDOT:PSS) to improve the electrochemical performance for uric acid detection. The SPCE was fabricated using a layer-by-layer painting process of conductive ink consisting of graphite as a conductive material, polystyrene as a polymeric binder, and dichloromethane solvent on a polyvinyl chloride paper substrate. The fabricated SPCE was then modified with PEDOT:PSS by a drop-casting method. The characterization of SPCE-PEDOT:PSS surface morphology was performed using the scanning electron microscopy technique. The SPCE-PEDOT:PSS provided an acceptable linearity (R2 = 0.9985, 0.9993, 0.9985), sensitivity (0.070, 0.015, 0.024 µA/µM), precision (%RSD = 2.70%, 2.89%, 2.40%), limit of detection (1.61 µM, 1.14 µM, 1.62 µM), and limit of quantitation (5.37 µM, 3.81 µM to 5.39 µM) in measurement of uric acid standard solution using cyclic voltammetry, amperometry, and differential pulse voltammetry techniques, respectively. The studies using SPCE-PEDOT:PSS indicated that the electrode could be applied in the electrochemical measurement of uric acid in the human urine sample.


2015 ◽  
pp. 97-102
Author(s):  
Ani Mulyasuryani ◽  
Alfita Savitri

Hydroquinone in whitening face cream has been banned since 2008, but is still found facial bleaching creams containing hydroquinone. Therefore, in this study have been developed voltammetric method for the determination hydroquinone in face whitening cream. This study has been carried out optimization of pH and measurement conditions. Optimizationof pH has been done in cyclic voltammetry, while the optimization of measurement carried out by differential pulse voltammetry. In this study, using a screen printed carbon electrode with a three electrode system. The results showed that the increase in pH causes a decrease in the anodic peak potential (Epa) of hydroquinone. The optimum conditions resulted at pH 2 in which the anodic current (Ipa) is the highest. The optimum condition resulted at high pulse 200 mV and scan rate at 15 mV/sec. The linear regression concentration is 1-100 μM, limit of detection is 0.015 μM and sensitivity is 0.0652 μM/µA. The results showed that the concentration of hydroquinone in the face whitening cream samples ranged from 0 to 0.02%DOI :http://dx.doi.org/10.15408/jkv.v0i0.3145.


2018 ◽  
Vol 55 (5B) ◽  
pp. 78
Author(s):  
Nguyen Xuan Viet

This research reported the simple method to determine of dopamine (DA) in the simultaneous presence of ascorbic acid (AA) and uric acid (UA). Three – electrode system manufactured by screen printing method was used due to its disposal and low cost. The screen printed carbon electrode (SPCE) was oxidized by electrochemical technique in acid medium. The capacity of oxidized electrode for selective detection of dopamine was confirmed in a sufficient amount of ascorbic acid and uric acid. The large separated peaks of DA from ascorbic acid and uric acid are observed. The peak separation between UA and DA, DA and AA was 110 mV and 160 mV, respectively. The bare SPCE cannot determine simultaneously AA and DA due to the overlap peaks of AA and DA around 0.2 V vs AgCl/Ag. This sensor also exhibited good sensitivity to DA with limit of detection 100 nM in phosphate buffer solution.


Biosensors ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 27 ◽  
Author(s):  
Samuel J. Rowley-Neale ◽  
Dale A. C. Brownson ◽  
Graham Smith ◽  
Craig E. Banks

We demonstrate a facile methodology for the mass production of graphene oxide (GO) bulk-modified screen-printed electrodes (GO-SPEs) that are economical, highly reproducible and provide analytically useful outputs. Through fabricating GO-SPEs with varying percentage mass incorporations (2.5%, 5%, 7.5% and 10%) of GO, an electrocatalytic effect towards the chosen electroanalytical probes is observed, which increases with greater GO incorporated compared to bare/graphite SPEs. The optimum mass ratio of 10% GO to 90% carbon ink produces an electroanalytical signal towards dopamine (DA) and uric acid (UA) which is ca. ×10 greater in magnitude than that achievable at a bare/unmodified graphite SPE. Furthermore, 10% GO-SPEs exhibit a competitively low limit of detection (3σ) towards DA at ca. 81 nM, which is superior to that of a bare/unmodified graphite SPE at ca. 780 nM. The improved analytical response is attributed to the large number of oxygenated species inhabiting the edge and defect sites of the GO nanosheets, which are able to exhibit electrocatalytic responses towards inner-sphere electrochemical analytes. Our reported methodology is simple, scalable, and cost effective for the fabrication of GO-SPEs that display highly competitive LODs and are of significant interest for use in commercial and medicinal applications.


2018 ◽  
Vol 69 (4) ◽  
pp. 854-859 ◽  
Author(s):  
Angela Miccoli ◽  
Patrizia Restani ◽  
Laura Floroian ◽  
Nicoleta Taus ◽  
Mihaela Badea ◽  
...  

Melatonin (N-acetyl-5-methoxytryptamin) is a ubiquitous molecule widely distributed in nature. It is a hormone produced by the pineal gland, which plays a role in the body�s sleep cycles and it is a powerful antioxidant. It is possible to find it in several foods (fruit, rice, corn) and as food supplement. Screen-printed carbon electrode (DRP-150) and graphene modified screen-printed electrode (DRP-110GPH) were tested as sensors for the detection of melatonin using electrochemical detection (differential pulse voltammetry), at different pH values (7.4, 7.0, and 6.4). Quantitative detection of melatonin was possible, with better results when graphene modified screen-printed electrodes were used. The pH influenced the position of the peak as well, with lowering the pH moves more in the right. Both electrodes have been tested on samples of food supplements containing melatonin, with good recovery degrees.


2021 ◽  
Vol 9 ◽  
Author(s):  
Sopit Phetsang ◽  
Duangruedee Khwannimit ◽  
Parawee Rattanakit ◽  
Narong Chanlek ◽  
Pinit Kidkhunthod ◽  
...  

A novel copper (II) ions [Cu(II)]-graphene oxide (GO) nanocomplex-modified screen-printed carbon electrode (SPCE) is successfully developed as a versatile electrochemical platform for construction of sensors without an additionally external redox probe. A simple strategy to prepare the redox GO-modified SPCE is described. Such redox GO based on adsorbed Cu(II) is prepared by incubation of GO-modified SPCE in the Cu(II) solution. This work demonstrates the fabrications of two kinds of electrochemical sensors, i.e., a new label-free electrochemical immunosensor and non-enzymatic sensor for detections of immunoglobulin G (IgG) and glucose, respectively. Our immunosensor based on square-wave voltammetry (SWV) of the redox GO-modified electrode shows the linearity in a dynamic range of 1.0–500 pg.mL−1 with a limit of detection (LOD) of 0.20 pg.mL−1 for the detection of IgG while non-enzymatic sensor reveals two dynamic ranges of 0.10–1.00 mM (sensitivity = 36.31 μA.mM−1.cm−2) and 1.00–12.50 mM (sensitivity = 3.85 μA.mM−1.cm−2) with a LOD value of 0.12 mM. The novel redox Cu(II)-GO composite electrode is a promising candidate for clinical research and diagnosis.


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