Automated spectrophotometric determination of clomipramine on a multicommutated flow system Original Research Article

An automated multicommutated flow system for the spectrophotometric determination of clomipramine in pharmaceutical preparations was developed. The method was based on the oxidation of clomipramine by ammonium monovanadate in acidic medium yielding a coloured product with an absorbance maximum at 620 nm. The reaction development was enhanced when the binary sampling approach was exploited to insert the sample into the carrier stream. This approach, consisting of the intercalation of small sample and reagent aliquots, led to a more efficient sample zone homogenisation. The determinations were carried out at two distinct sampling times (6 and 12 s) in order to evaluate the system’s performance under different dispersion conditions, which also showed the versatility of the multicommutation time-based sample insertion. Beer’s law was verified for clomipramine concentrations of up to 50 mg l−1. R.S.D. (n=10)<2.0 and 1.3% were attained for sampling times of 6 and 12 s, respectively. The results were in agreement with those obtained by the reference procedure, with R.D.<2.6%.