Simultaneous voltammetric sensing of levodopa, piroxicam, ofloxacin and methocarbamol using a carbon paste electrode modified with graphite oxide and [beta]-cyclodextrin

• Published in: Mikrochimica acta (1966) Vol. 186; no. 3
• Main Authors: Santos, Anderson Ma, Wong, Ademar, Vicentini, Fernando Campanhã, Fatibello-Filho, Orlando
• Format: Journal Article
• Language: English
• Published: Springer 01.03.2019
• Subjects: Cyclodextrins; Dopa; Graphite; Methocarbamol; Ofloxacin; Piroxicam; Sensors
• ISSN: 0026-3672; 1436-5073
• DOI: 10.1007/s00604-019-3296-x

A carbon paste electrode (CPE) was modified with graphite oxide (GrO) and [beta]-cyclodextrin (CD) to obtain a sensor for simultaneous voltammetric determination of levodopa (LD), piroxicam (PRX), ofloxacin (OFX) and methocarbamol (MCB). The morphology, structure and electrochemical properties of the functionalized GrO were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, contact angle measurements and cyclic voltammetry. Under the optimal experimental conditions, the sensor is capable of detecting LD, PRX, OFX and MCB by square wave voltammetry (SWV) at working potentials of +0.40, +0.60, +1.03 and + 1.27 V (versus Ag/AgCl), respectively. Response is linear from 1.0 to 20 [mu]M for LD, from 1.0 to 15 [mu]M for PRX, from 1.0 to 20 [mu]M for OFX, and from 1.0 to 50 [mu]M for MCB. The respective limits of detection are 65, 105, 89 and 400 nM. The method was successfully applied to the simultaneous determination of LD, PRX, OFX and MCB in (spiked) real river water and synthetic urine samples, and the results were in agreement with those obtained using a spectrophotometric method, with recoveries close to 100%.