A glassy carbon electrode modified with reduced graphene oxide for sensitive determination of bumetanide in urine at levels required for doping analysis

Abstract

The dopant bumetanide (BMT) was banned by the World Anti-Doping Agency. The authors describe a voltammetric sensor for the determination of BMT in urine that is based on the use of a glassy carbon electrode modified with reduced graphene oxide (GCE/rGO). The GCE/rGO was prepared by electrodeposition from a solution of GO. The oxidation of BMT occurs best at +0.75 V in the GCE/rGO with an approximately 13-fold gain in the anode current compared to a conventional GCE. The oxidation mechanism was investigated by means of electrolysis, while the analysis of the products was carried out via the LC-MS/MS. Under optimized conditions (scan rate 100 mV s −1 ; pH 4.0; accumulation time 25 s) and by using linear sweep adsorptive stripping voltammetry, the response covers the 0.26 to 50 μmol L −1 BMT concentration range. The detection limit is 75 nmol L −1. The sensor was successfully applied and validated by LC-MS/MS analysis of spiked urine sample.

Enhanced Detection of Ponceau 4R Food Dye by Glassy Carbon Electrode Modified with Reduced Graphene Oxide

“…The r-GO/GCE was prepared through the electrodeposition of the previously prepared graphene oxide suspension in a glassy carbon electrode applying a potential of −1.4 V for 500 s, forming a stable and reproducible film. 28,29 After each modification, the sensor was subjected to successive voltammetric cycles (15 cycles) in the range of 0.40 to 1.1 V in 0.1 mol L −1 BR buffer solution at a scan rate of 75 mV s −1 for stabilization of the modified electrode surface.…”

Research on Detection of Sterol Doping in Sports by Electrochemical Sensors: A Review

“…Diuretics rapidly reduce the concentration of other stimulants and their metabolites in body uids and excreta in a short time, a ecting the accuracy of drug test results. Diuretics can interfere with drug testing, resulting in false negative omissions [10][11][12][13]. Diuretics and masking agents are high-incidence stimulants.…”

Electrochemical Determination of the Steroid Tibolone and Its Metabolites in Saliva Samples

“…Therefore, TIB was included in the group "S1 -Anabolic Agents" since 2006 and in the subgroup of "other anabolic agents" in the annual list of prohibited substances in sports by the World Anti-Doping Agency (WADA) [6] which is used by world institutions, such as the International Olympic Committee and the International Federation of Football Association (FIFA). [7] These prohibited substances can be used to improve athletic performance, such as increase in muscle mass by increasing protein synthesis, inhibiting protein catabolism, increased nitrogen retention and stimulation of red blood cell production, in addition to favoring increased aggressiveness and motivation. [8][9][10] Therefore, the development of simple, low-cost, and sensitive analytical methods to determine TIB or its metabolites in biological fluids (e. g., saliva samples) is highly relevant.…”