Advanced sensing performance towards simultaneous determination of quaternary mixture of antihypertensives using boron-doped diamond electrode

An advanced, simple and rapid voltammetric method for a quaternary mixture determination of antihypertensive drugs, namely amlodipine besylate (AML), amiloride hydrochloride (AMI), hydrochlorothiazide (HCTZ) and atenolol (ATN), is described. An anodically pretreated boron-doped diamond electrode (using + 0.5 A cm− 2 during 30 s in 0.5 mol L− 1 H2SO4) was employed for square-wave voltammetric determination of these drugs with very well-resolved and reproducible oxidative peaks at 0.68, 0.89, 1.04 and 1.21 V (vs Ag/AgCl (3.0 mol L− 1 KCl)), respectively, in ammonium buffer solution (pH 9.0). Using optimized experimental conditions, the corresponding peaks heights increased linearly within the concentration range of 0.90-31, 8.7-125, 29-260 and 11-91 μmol L− 1 with detection limit of 0.30, 0.09, 0.08 and 0.06 μmol L− 1 for AML, AMI, HCTZ and ATN, respectively. The viability of the proposed method was successfully assessed by simultaneous quantification of the studied drugs in commercially available pharmaceutical formulations and also in spiked tap water sample with the recovery values ranged from 93.9 to 104%. The accuracy of the developed protocol was proven statistically by comparison with high performance liquid chromatography as a reference (comparative) method. The accomplished results fortify the fact that the boron-doped diamond electrode in connection with the square-wave voltammetric technique may constitute an advanced electroanalytical platform for simple and rapid simultaneous determination of various biologically active substances to replace chemically modified electrodes, especially in drug sensing.