Graphene Modified Molecular Imprinting Electrochemical Sensor for Determining the Content of Dopamine

2019 ◽  
Vol 15 (6) ◽  
pp. 628-634
Author(s):  
Rong Liu ◽  
Jie Li ◽  
Tongsheng Zhong ◽  
Liping Long

Background: The unnatural levels of dopamine (DA) result in serious neurological disorders such as Parkinson’s disease. Electrochemical methods which have the obvious advantages of simple operation and low-cost instrumentation were widely used for determination of DA. In order to improve the measurement performance of the electrochemical sensor, molecular imprinting technique and graphene have always been employed to increase the selectivity and sensitivity. Methods: An electrochemical sensor which has specific selectivity to (DA) was proposed based on the combination of a molecular imprinting polymer (MIP) with a graphene (GR) modified gold electrode. The performance and effect of MIP film were investigated by differential pulse voltammetry (DPV) and cyclic voltammetry (CV) in the solution of 5.0 ×10-3 mol/L K3[Fe(CN)6] and K4[Fe(CN)6] with 0.2 mol/L KCl at room temperature. Results: This fabricated sensor has well repeatability and stability, and was used to determine the dopamine of urine. Under the optimized experiment conditions, the current response of the imprinted sensor was linear to the concentration of dopamine in the range of 1.0×10-7 ~ 1.0×10-5 mol/L, the linear equation was I (µA) = 7.9824+2.7210lgc (mol/L) with the detection limit of 3.3×10-8 mol/L. Conclusion: In this work, a highly efficient sensor for determination of DA was prepared with good sensitivity by GR and great selectivity of high special recognization ability by molecular imprinting membrane. This proposed sensor was used to determine the dopamine in human urine successfully.

2020 ◽  
Vol 20 (6) ◽  
pp. 3356-3360
Author(s):  
Hao Yong Yin ◽  
Yi Fan Zheng ◽  
Ling Wang

We report the formation of gold nanoparticles on indium tin oxide conducting glass (ITO) surface via electrodeposition method at room temperature. The prepared nano-Au electrodes has been fabricated for sensitive detection of Pb2+, and showed highly selective response toward Pb2+. The electrochemical detection of Pb2+ were determined by differential pulse stripping voltammetric (DPSV). The nano-Au electrochemical sensor could detect Pb2+ from 0.5 to 10 μM with detection limits of 0.06 μM (S/N= 3) and sensitivity of 0.27996 mA μM−1. The proposed sensor is simple, reliable, sensitive, selective, and low-cost, thus holds potential for practical application in Pb2+ detection.


2014 ◽  
Vol 6 (17) ◽  
pp. 6885-6892 ◽  
Author(s):  
Ali A. Ensafi ◽  
F. Saeid ◽  
B. Rezaei ◽  
Ali R. Allafchian

A new electrochemical method was developed for epinephrine detection based on NiFe2O4–MWCNT-modified electrode. The nanocomposite has a synergic effect on the oxidation of epinephrine.


2016 ◽  
Vol 8 (45) ◽  
pp. 8028-8032
Author(s):  
Taimara Polidoro Ferreira ◽  
Rafael Arromba de Sousa ◽  
Denise Lowinsohn

The simultaneous electrochemical determination of lead (Pb) and cadmium (Cd) in low-cost jewelry was achieved using differential pulse voltammetry (DPV).


2019 ◽  
Vol 9 (3) ◽  
pp. 416-422
Author(s):  
Rafael Souza Antunes ◽  
Douglas Vieira Thomaz ◽  
Luane Ferreira Garcia ◽  
Eric de Souza Gil ◽  
Vernon Sydwill Sommerset ◽  
...  

Purpose: Jenipapo fruit (Genipa americana L) is a natural source of polyphenol oxidases (PPOs) whose potential in pharmaceutical analysis is noteworthy. Henceforth, this work reports the electrochemical study of a low-cost PPO-based biosensor produced from the crude extract of Jenipapo fruits and accounts a practical approach to employ this biosensor in the determination of methyldopa and paracetamol in pharmaceutical samples. Methods: In order to investigate the electrochemical properties of the biosensor, theoretical and practical approaches were employed, and both samples and the biosensor were analyzed through electrochemical impedance spectroscopy (EIS) and voltammetric techniques, namely: differential pulse voltammetry (DPV) and cyclic voltammetry (CV). Results: showcased that the biosensor presented good analytical features, as well as low detection limits (8 μmol L-1 for methyldopa and 5 μmol L-1 for paracetamol). The relative standard deviation was less than 5% mid-assay. Conclusion: The use of this biosensor is a reliable, low cost and useful alternative in the pharmaceutic determination of phenolic drugs (e.g. methyldopa and paracetamol).


2017 ◽  
Vol 10 (1) ◽  
pp. 21-28 ◽  
Author(s):  
Ivana Sálusová ◽  
Kristína Cinková ◽  
Barbora Brtková ◽  
Marian Vojs ◽  
Marián Marton ◽  
...  

Abstract The electrochemical behavior and determination of ascorbic acid (AA) was investigated at a bare boron-doped diamond (BDD) electrode using cyclic and differential pulse voltammetry. The influence of pH of supporting electrolyte and scan rate on the current response of analyte was examined to select the suitable experimental conditions. It was found that AA provided one well-shaped irreversible and diffusioncontrolled oxidation peak at +0.87 V vs. Ag/AgCl in Britton-Robinson buffer pH 4.0. Applying differential pulse voltammetry, the peak current of AA was linearly proportional to its concentration from 5 × 10-6 to 2 × 10-4 mol L-1 (R2 = 0.999), with the limit of detection of 1.1 × 10-6 mol L-1 and the good repeatability (relative standard deviation of 2.3 %). The developed electroanalytical protocol was successfully applied to determine the content of AA in commercial pharmaceutical preparations, based on the standard additions method, with the obtained recovery of 122 %. The accomplished analytical performance indicates that BDD electrodes are promising electrochemical sensors for pharmaceutical analysis.


Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 268 ◽  
Author(s):  
Xiao-Zhen Feng ◽  
Annaleizle Ferranco ◽  
Xiaorui Su ◽  
Zhencheng Chen ◽  
Zhiliang Jiang ◽  
...  

Simple and facile electrochemical sensors for nitrite detection were fabricated by directly depositing ferrocenoyl cysteine conjugates Fc[CO-Cys(Trt)-OMe]2 [Fc(Cys)2] or Fc[CO-Glu-Cys-Gly-OH] [Fc-ECG] on screen-printed electrodes (SPEs). The modified carbon electrodes were characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Results indicated that Fc-ECG/SPE sensor showed enhanced current response and a lower overpotential than Fc(Cys)2/SPE sensor for nitrite detection. Optimal operating conditions were estimated for nitrite detection by DPV. The concentration of nitrite showed a good linear relationship with the current response in the range of 1.0–50 μmol·L−1 and with 0.3 μmol·L−1 as the concentration for limit of detection. There were no interferences from most common ions. The development of this electrochemical sensor was used for nitrite detection in pickled juice with a R.S.D. lower than 2.1% and average recovery lower than 101.5%, which indicated that disposable electrochemical sensor system can be applied for rapid and precise nitrite detection in foods.


2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Serge Foukmeniok Mbokou ◽  
Maxime Pontié ◽  
Jean-Philippe Bouchara ◽  
Francis Merlin Melataguia Tchieno ◽  
Evangeline Njanja ◽  
...  

Electrochemical determination of acetaminophen (APAP) was successfully performed using a carbon paste electrode (CPE) modified with coffee husks (CH-CPE). Scanning electron microscopy (SEM) and SEM-energy dispersive X-ray spectroscopy (SEM-EDX) were, respectively, used for the morphological and elemental characterization of coffee husks prior to their utilization. The electrochemical oxidation of APAP was investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and square wave voltammetry (SWV). SWV technique appeared to be more sensitive since the oxidation current of APAP was twofold higher with the CH-CPE sensor than with the bare CPE, in relation to the increase in the organophilic character of the electrode surface. Furthermore, on CH-CPE, the current response of APAP varied linearly with its concentration in the range of 6.6 μM to 0.5 mM, leading to a detection limit of 0.66 μM (S/N=3). Finally, the proposed CH-CPE sensor was successfully used to determine the amount of APAP in commercialized tablets (Doliprane® 500 and Doliprane 1000), with a recovery rate ranging from 98% to 103%. This novel sensor opens the way for the development of low-cost and reliable devices for the electroanalysis of pharmaceutical formulations in developing countries.


2019 ◽  
Vol 15 (6) ◽  
pp. 648-655 ◽  
Author(s):  
Shengzhong Rong ◽  
Deng Pan ◽  
Xuehui Li ◽  
Mucong Gao ◽  
Hongwei Yu ◽  
...  

Background: 8-Hydroxy-2’-deoxyguanosine (8-OHdG) has been regarded as a typical stable biomarker of DNA oxidative damage, and its level is one of the criteria for early diagnosis of various diseases. Considering the significance of 8-OhdG, various analytical techniques have been used for assaying 8-OHdG but all of them suffer from basic limitations like highly expensive instrumentation, large amount of sample requirement, complicated sample pre-treatment, tedious and time-consuming procedures etc. However, electroanalytical sensors provide a faster, easy and sensitive means of analyzing. Methods: The chitosan (CS) film provided the high electrode activity and stability which is required for detecting 8-OHdG though direct electrochemical oxidation. Zirconia was employed because it has some unique properties, such as high redox activity and selectivity etc. High-performance composite was easily detected by differential pulse voltammetry at a working voltage of 0. 51 V (vs. Ag/AgCl). A rapid and sensitive electrochemical sensor based on CS and metal oxide nanocrystalline for the determination of 8-OHdG was established. Results: Under optimized experimental conditions, the peak currents of differential pulse voltammetry increased as the concentrations of 8-OHdG increased from 10 to 200 ng·mL-1. The detection limit was 3.67 ng·mL-1 which was calculated by the S/N ratio of 3. The recoveries of the real spiked samples are in the range between 93.2 to 105.3%. Conclusion: The electrochemical sensor for direct 8-OHdG determination using a new CS/zirconia composite for GCE modification was developed and showed excellent reproducibility, stability and sensitivity for the specific determination of 8-OHdG in real urine specimen.


Author(s):  
Hamid Sarhadi ◽  
Zare Maryam

In the field of determination of vitamin B9 (folic acid, FA), we have described the development of a sensitive electrochemical sensor through promoting the screen-printed electrode (SPE) and taking the advantage of zinc ferrite magnetic nanoparticles (ZnFe2O4MNPs). Cyclic voltammetry (CV) experiments demonstrated the powerful activity of ZnFe2O4MNPs/SPE for electrooxidation of FA by showing the prominent oxidation peak at 600 mV vs. Ag/AgCl. By differential pulse voltammetry (DPV) measurements, a linear relation between current response and concentration of vitamin B9 was determined in the range of 1.0–100.0 µM, and detection limit is found to be 0.3 µM (S/N=3). Except high sensitivity, the developed sensor demonstrated high stability, reproducibility and repeatability, and was also successfully applied to specify FA in real samples of vitamin B9 tablets and human urine.


2020 ◽  
Vol 17 (4) ◽  
pp. 1198
Author(s):  
Santhy Wyantuti ◽  
Zulida Setyorini ◽  
Safri Ishmayana ◽  
Yeni Hartati ◽  
M Firdaus

This study was aimed to develop an optimized Dy determination method using differential pulse voltammetry (DPV). The Plackett-Burman (PB) experimental design was used to select significant factors that affect the electrical current response, which were further optimized using the response surface method-central composite design (RSM-CCD). The type of electrolyte solution and amplitude modulation were found as two most significant factors, among the nine factors tested, which enhance the current response based on PB design. Further optimization using RSM-CCD shows that the optimum values for the two factors were 0.1046 M and 0.1082 V respectively. When the optimum conditions were applied for Dy determination good recovery and precision were achieved with values of 91.58%, and 99.80%, respectively. The detection limit and quantification limit of the method were 1.4322 mg/L and of 4.7741 mg/L, respectively.


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