Journal of Electroanalytical Chemistry, Vol.754, 154-159, 2015
Simultaneous determination of antihypertensive drugs by flow injection analysis using multiple pulse amperometric detection with a cathodically pretreated boron-doped diamond electrode
A flow injection analysis (FIA) and multiple pulse amperometric detection (MPA) using a cathodically pretreated boron-doped diamond electrode (CPT-BDD) were employed for simultaneous determination of the antihypertensive drugs hydrochlorothiazide (HTZ) and enalapril (ENP). A dual-potential waveform as a function of time, previously optimized, was used: E-det.1 = +1.50 V / 150 ms (pulse potential at which HTZ was oxidized) and E-det.2 = +1.80 V / 150 ms (pulse potential at which oxidation of both analytes - HTZ and ENP - occurs). The analytical curves presented good linearity from 0.40 to 8.00 mu mol L-1 for HTZ and from 0.03 to 1.00 mu mol L-1 for HTZ, and the detection limits were 0.20 mu mol L-1 for HTZ and 0.01 mu mol L-1 for ENP. The proposed flow method presented an analytical frequency of 89 determinations per hour, good precision and accuracy, was successfully applied to the simultaneous determination of HTZ and ENP in pharmaceutical samples and the results obtained using the FIA-MPA method were in agreement with those obtained using a comparative method (HPLC) at a 95% confidence level. (C) 2015 Elsevier B.V. All rights reserved.