Amperometric flow-injection determination of the anthelmintic drugs ivermectin and levamisole using electrochemically pretreated boron-doped diamond electrodes

Abstract

Sensitive, simple, low-cost, and rapid amperometric flow-injection methods were developed for determination of ivermectin (IVM) and levamisole (LVM) in anthelmintic pharmaceutical drugs and urine samples. These determinations were carried out with a cathodically (for IVM) or anodically (for LVM) pretreated boron-doped diamond electrode using aqueous 0.5molL−1 H2SO4 (with and without addition of 30% V/V of ethanol) as supporting electrolyte. The amperometric detection was performed at an applied electrode potential of E=1.40V, for IVM, and E=1.90V, for LVM, vs. Ag/AgCl (3.0molL−1 KCl). The respective analytical curves presented good linearity in the investigated concentration ranges (0.60–50μmolL−1, for IVM, and 0.010–5.0μmolL−1, for LVM) and the detection limits were 0.30μmolL−1 for IVM, and 1nmolL−1, for LVM. Investigation of possible interferents showed no significant interference with the here-proposed methods; thus, they were used to determine IVM and LVM in pharmaceutical formulations as well as in urine samples, with results that showed good agreement with comparative methods. Furthermore, a mechanism for LVM electrooxidation was proposed using exhaustive potentiostatic electrolysis and NMR measurements.