Anodic Stripping Voltammetric Determination of Aurothiomalate in Urine Using a Screen‐Printed Carbon Electrode

Abstract

This work describes an electroanalytical method for determining gold(I) thiomalate, aurothiomalate, widely used for treatment of reumatoid arthiritis, using a screen-printed carbon electrode (SPCE). Aurothiomalate (AuTM) was determined indirectly at the same electrode by accumulating it first at À 1.5 V vs. printed carbon. At this potential in the adsorbed state, the AuTM is reduced to Au(0), which is then oxidized at two steps at À 0.22 V and þ 0.54 V on SPCE. Using optimized conditions of 60 s deposition time, À 1.5 V (vs. printed carbon) accumulation potential, 100 mV s À1 scan rate, linear calibration graphs can be obtained by monitoring the peak at þ 0.54 V for AuTM in HCl 0.1 mol L À1 from 1.43 Â 10 À6 to 1.55 Â 10 À4 mol L À1 . A limit of detection obtained was 6.50 Â 10 À7 mol L À1, and the relative standard deviation from five measurements of 3.0 Â 10 À5 mol L À1 AuTM is 4.5%. The method was successfully applied for AuTM determination in human urine sample.

Screen-printed carbon electrode modified with poly-L-histidine applied to gold(III) determination

“…This peak current can be attributed to the reduction of gold(III) species to gold(I). 17,19,33 The response on the screen-printed carbon electrode coated with poly-L-histidine (SPCE/PH) film is essentially the same. However, there is an increase in the peak intensity for both experiments (curve b), while a bigger increase is observed in the chloride medium.…”

“…The urine sample (10.0 mL) was then acidified with 1.0 mL of hydrochloric acid and the solution was heated for 20 min at 80 ºC to hydrolyze any proteins that may have been present in the sample. 33 The solution yielded was diluted with 0.1 mol L -1 KCl (pH 1.0) solution at a ratio 200 µL to a 10.0 mL final volume. The gold-ion content in these samples was determined using the standard addition method of gold(III) stock solution in four successive additions in order to obtain a final added gold ion concentration of 0.5, 1.0, 2.0 and 4.0 µmol L -1 , respectively.…”

Effect of Scan Rate and pH on Determination Amoxilline Using Screen Printed Carbon Electrode Modified With Functionalized Graphene Oxide

“…Oviedo, Spain).The principle function of a potentiostatis controlling potential and measuring current; which was connected via a USB connection to laptop computer installed with the measurement software Drop View (DropSens DRP-110). The measurement was made with screen printed carbon electrode (SPCE) having, carbon counter electrode CE, silver/silver chloride reference electrode RE and a carbon working electrode WE (4 mm diameter) printed on a ceramic surface [8],a small area enables very small sample to perfome the measurement. Volumes smaller than 10 μl deposited directly on the electrode surface [9] are adequate for the analysis.…”

“…,°= ° ( / )−2.303 ∕ (8) ,° was an effective formal potential, the potential midway between the peaks for redox peaks for A and B. The dependence formal redox potential ° of AMOX on the pH was investigated by cyclic voltammetry.…”

Development of Electro-Analytical Methods Using Electrochemical Carbon-Based Sensors for Determination of Trifloxystrobin, Gentamicin and Lapachol

“…Surfactants might play important roles in electrochemical processes since they can mediate the interaction between electroactive species and electrode [177,178]. Surfactants might influence redox processes and minimize the passivation of the electrode surface caused by adsorption of electrogenerated products or by sample matrix components [179,180]. In addition, they improve the solubility of more hydrophobic analytes and facilitate mass transport [181,182].…”