scholarly journals The use of a gold electrode for the determination of amphetamine derivatives and application to their analysis in human urine

2013 ◽  
Vol 78 (9) ◽  
pp. 1373-1385 ◽  
Author(s):  
Marina Nevescanin ◽  
Milka Avramov-Ivic ◽  
Slobodan Petrovic ◽  
Dusan Mijin ◽  
Sonja Banovic-Stevic ◽  
...  
Keyword(s):  
Quantitative Determination ◽  
Human Urine ◽  
High Performance ◽  
Gold Electrode ◽  
Simple Procedure ◽  
Reference Method ◽  
Linear Increase ◽  
Urine Samples ◽  
Amphetamine Derivatives

The catalytic abilities of gold electrode were tested for the quantitative determination of amphetamine (A) and 3,4-methylenedioxy-N-methylamphetamine (MDMA) standards by their oxidation using cyclic voltammetry (CV). The value of the oxidative currents of A and MDMA standards at 0.80 V vs. SCE in 0.05 M NaHCO3 at the scan rate of 50 mV/s is linear function of concentration in range of 110.9-258.9 mM and 38.7-229.2 mM, respectively. Square wave voltammetry (SWV) revealed linear increase of current with concentration of MDMA (range 30.9-91.6 mM) and thus quantitative determination of amphetamine derivates. SWV analysis is successfully performed in spiked urine samples as well. A and MDMA in the presence of sucrose and as a content in illegally produced tablets were also analyzed. The voltammetric determination of A and MDMA derivatives using CV and SWV at gold electrode is a rapid, selective and simple procedure and its accuracy was confirmed with reference method, high performance liquid chromatography (HPLC). The spiked urine samples analysis offers additional possibility for the rapid detection of A and MDMA in human urine.

Development of Dispersive Liquid-Liquid Microextraction Procedure for Trace Determination of Malathion Pesticide in Urine Samples

2020 ◽  
Author(s):  
Maryam RAMIN ◽  
Monireh KHADEM ◽  
Fariborz OMIDI ◽  
Mehran POURHOSEIN ◽  
Farideh GOLBABAEI ◽  
...  
Keyword(s):  
Enrichment Factor ◽  
Human Urine ◽  
High Performance ◽  
Limit Of Detection ◽  
Urine Samples ◽  
Human Urine Samples ◽  
Extraction Solvent ◽  
Ultraviolet Detector ◽  
Relative Standard

Background: Measurement of pesticides in biological matrices is become a serious challenge for researches because of their very low concentration in different matrices. The aim of this study was to develop a new sample preparation method with high accuracy and validity, simplicity and short retention time for determination of malathion. Methods: Dispersive liquid-liquid micro-extraction (DLLME) technique coupled with high-performance liquid chromatography equipped with ultraviolet detector (HPLC-UV) developed for trace extraction and determination of malathion pesticide in human urine samples. This study was done in 2017 at Tehran University of Medical Sciences, Tehran, Iran. One variable at a time (OVAT) method was used to optimize parameters affecting the malathion extraction. Different parameters such as extraction solvent, disperser solvent, and volume of the extraction solvent, volume of the disperser solvent, centrifugation time and speed, salt addition, and sample pH were studied and optimized. Results: Under the optimized conditions, the limit of detection and enrichment factor of the method were 0.5 µg L-1 and 200, respectively. The calibration curve was linear in the concentration range of 2-250 µg L-1 . The relative standard deviation for six replicate experiments at 200 µg L-1 concentration was less than 3%. The relative recoveries of spiked urine samples were 96.3%, 101.7% and 97.3% at three different concentration levels of 50, 200 and 1000 µg L-1 , respectively. Conclusion: DLLME procedure was successfully developed for the extraction of malathion from human urine samples. Compared to other extraction techniques, the proposed procedure had some advantages such as shorter extraction time, better reproducibility, and higher enrichment factor.  

scholarly journals Modification of screen printed gold electrode with 1,4-dithiothreitol: Application to sensitive voltammetric determination of Sudan II

2020 ◽  
Author(s):  
Kuddusi Karaboduk
Keyword(s):  
High Performance ◽  
Gold Electrode ◽  
Electrochemical Impedance ◽  
Reference Method ◽  
Differential Pulse ◽  
Peak Current ◽  
Ft Ir ◽  
Recovery Percentage ◽  
Screen Printed

Abstract Objectives The aim of this study is to investigate the electrochemical behavior of Sudan II (SuII) using a screen printed gold electrode (SPGE) modified with 1,4-dithiothreitol (DTT) and to determine the amount of Sudan II by voltammetry. Materials and Methods A DTT modified screen printed gold electrode (DTT/SPGE) was fabricated and its application for differential pulse voltammetric (DPV) determination of SuII was reported. Fourier transform infrared spectroscopy (FT-IR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy were used for the characterization of modified electrode. The effects of instrumental and chemical parameters were optimized for the determination of SuII. The fabricated electrode was used for the analysis of SuII in fortified and real samples. High performance liquid chromatography (HPLC) was preferred as a reference method for the evaluation of the obtained voltammetric results. Results The electrochemical studies and FT-IR demonstrated that the SPGE was modified with DTT. The obtained peak current at DTT/SPGE was 6.67 times higher than that recorded with SPGE. At the optimized conditions of DPV in pH = 2.5 of H2SO4, the oxidation peak current of SuII was proportional to its concentration in range: 0.001 - 1.500 μmol L -1 with a detection limit of 0.0002 μmol L -1 (S/N=3). For the analysis of SuII, 101.67 - 104.33% of recovery percentage was obtained. Conclusions A new electrode was successfully improved for the determination of SuII. This highly selective and sensitive electrode supplied the fast determination of SuII in ketchup, chili sauce and salsa dip sauce. In addition, voltammetric and chromatographic results are found to be consistent.

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