Highly sensitive and rapid determination of sunset yellow in drinks using a low-cost carbon material-based electrochemical sensor

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.

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Immobilization of Pseudomonas aeruginosa static biomass on eggshell powder for on-line preconcentration and determination of Cr (VI)

Open Chemistry ◽

10.1515/chem-2020-0031 ◽

2020 ◽

Vol 18 (1) ◽

pp. 303-313 ◽

Cited By ~ 1

Author(s):

Aamir Rasheed ◽

Tahseen Ghous ◽

Sumaira Mumtaz ◽

Muhammad Nadeem Zafar ◽

Kalsoom Akhter ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Low Cost ◽

Colorimetric Detection ◽

Time Flow ◽

Highly Sensitive ◽

Glass Column ◽

On Line ◽

Preconcentration Time ◽

Ultra Trace

AbstractIn the present work, a novel continuous flow system (CFS) is developed for the preconcentration and determination of Cr (VI) using Pseudomonas aeruginosa static biomass immobilized onto an effective and low-cost solid support of powdered eggshells. A mini glass column packed with the immobilized biosorbent is incorporated in a CFS for the preconcentration and determination of Cr (VI) from aqueous solutions. The method is based on preconcentration, washing and elution steps followed by colorimetric detection with 1,5-diphenyl carbazide in sulphuric acid. The effects of several variables such as pH, retention time, flow rate, eluent concentration and loaded volume are studied. Under optimal conditions, the CFS method has a linear range between 10 and 100 μg L-1 and a detection limit of 6.25 μg L-1 for the determination of Cr (VI). The sampling frequency is 10 samples per hour with a preconcentration time of 5 mins. Furthermore, after washing with a 0.1 M buffer (pH 3.0), the activity of the biosorbent is regenerated and remained comparable for more than 200 cycles. Scanning electron microscopy reveals a successful immobilization of biomass on eggshells powder and precipitation of Cr (VI) on the bacterial cell surface. The proposed method proves highly sensitive and could be suitable for the determination of Cr (VI) at an ultra-trace level.

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Applicability of Cork as Novel Modifiers to Develop Electrochemical Sensor for Caffeine Determination

Materials ◽

10.3390/ma14010037 ◽

2020 ◽

Vol 14 (1) ◽

pp. 37

Author(s):

Mayra K. S. Monteiro ◽

Djalma R. Da Silva ◽

Marco A. Quiroz ◽

Vítor J. P. Vilar ◽

Carlos A. Martínez-Huitle ◽

...

Keyword(s):

Electrochemical Sensor ◽

Linear Response ◽

High Performance ◽

Low Cost ◽

Pharmaceutical Formulations ◽

Caffeine Concentration ◽

Real Samples ◽

Wide Range ◽

Potential Use

This study aims to investigate the applicability of a hybrid electrochemical sensor composed of cork and graphite (Gr) for detecting caffeine in aqueous solutions. Raw cork (RAC) and regranulated cork (RGC, obtained by thermal treatment of RAC with steam at 380 °C) were tested as modifiers. The results clearly showed that the cork-graphite sensors, GrRAC and GrRGC, exhibited a linear response over a wide range of caffeine concentration (5–1000 µM), with R2 of 0.99 and 0.98, respectively. The limits of detection (LOD), estimated at 2.9 and 6.1 µM for GrRAC and GrRGC, suggest greater sensitivity and reproducibility than the unmodified conventional graphite sensor. The low-cost cork-graphite sensors were successfully applied in the determination of caffeine in soft drinks and pharmaceutical formulations, presenting well-defined current signals when analyzing real samples. When comparing electrochemical determinations and high performance liquid chromatography measurements, no significant differences were observed (mean accuracy 3.0%), highlighting the potential use of these sensors to determine caffeine in different samples.

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Highly Sensitive Nanostructured Electrochemical Sensor Based on Carbon Nanotubes-Pt Nanoparticles Paste Electrode for Simultaneous Determination of Levodopa and Tyramine

Russian Journal of Electrochemistry ◽

10.1134/s1023193517120023 ◽

2018 ◽

Vol 54 (3) ◽

pp. 292-301 ◽

Cited By ~ 14

Author(s):

Mehdi Baghayeri ◽

Hadi Beitollahi ◽

Ali Akbari ◽

Samaneh Farhadi

Keyword(s):

Carbon Nanotubes ◽

Electrochemical Sensor ◽

Simultaneous Determination ◽

Pt Nanoparticles ◽

Highly Sensitive ◽

Paste Electrode

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Electrochemical Sensor for Determination of Pb2+ Based on Gold Nanoparticles

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2020.17415 ◽

2020 ◽

Vol 20 (6) ◽

pp. 3356-3360

Author(s):

Hao Yong Yin ◽

Yi Fan Zheng ◽

Ling Wang

Keyword(s):

Gold Nanoparticles ◽

Electrochemical Sensor ◽

Electrochemical Detection ◽

Tin Oxide ◽

Indium Tin Oxide ◽

Room Temperature ◽

Low Cost ◽

Differential Pulse ◽

Practical Application

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.

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