Abstract
Oxidation behavior of tretinoin (TRN) was evaluated using anodic stripping voltammetry (ASV), differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques in Britton-Robinson (B-R) pH 7. The glassy carbon (GC) electrode was used to deposit the compound (TRN) into its surface to record a well-defined oxidation peak at 0.75 V in the presence of Ag/AgCl reference electrode and a Pt counter electrode. Some analytical parameters were studied to obtain the best oxidation signal, for example; buffer solution, pH, accumulation potential and time, amplitude, frequency, scan rate and convection rate. The high sensitivity anodic peak was obtained using B-R, pH 7, 40 s accumulation time, −0.6 V accumulation potential, 50 mV amplitude, 20 Hz frequency, 350 mV s−1 scan rate, and 1000 rpm. These parameters were chosen as optimum conditions for the continued experiments. The analytical performance of the used technique was evaluated using the study of repeatability, stability, recovery, calibration curve and detection limit. Repeatability and stability was monitored for 5 × 10−6 mol L−1 of TRN to give 0.24% relative standard deviation (RSD%) for eighth anodic measurements, while the stability was been very well for 80 min. The calibration curve was studied over the range of 1 × 10−6–1 × 10−5 mol L−1 (n = 6), yielded, a linear relationship between concentrations and anodic current for TRN. A detection limit (LOD) was calculated to be 7.5 × 10−9 mol L−1 (2.25 ppb), while a quantification limit (LOQ) was yielded 2.49 × 10−8 mol L−1 (7.47 ppb). Anodic stripping voltammetry method was developed and applied for the determination of TRN in the human urine and plasma samples.