Abstract
An inexpensive, rapid, safe and green method for pindolol assay in medicines was developed using sequential injection analysis (SIA) technique. The method was based on the oxidation of pindolol by dichromate in sulfuric acid media. A chromogenic form of pindolol was spectrophotometrically detected at 640 nm. The 3(3) full-factorial design approach was applied to optimize acid concentration, pindolol volume and reaction time. The automation of SIA and the optimization process offered satisfactorily selectivity to the method. The recovery of pindolol in the presence of clopamide as a companion drug, besides excipients usually found in tablet formulation, was in the range of 96.5-98.4%. The automation also provided good repeatability, with a relative standard deviation value of 2.2% for seven replicates. Additionally, the miniaturization of SIA rendered the method reagent-saving (the total consumed reagent volumes was 120 mu L) and environ-mentally-friendly (the total waste volume was 1320 mu L). Furthermore, both the automation and miniaturization offered a rapid procedure (the sample frequency was 22 samples/h). On the other hand, the chemometric optimization improved the detectability of the method with the limits of detection and quantification of 0.57 and 1.9 mu g/mL, respectively.