CHEMOMETRICAL OPTIMIZATION FIA OF PERPHENAZINE ASSAY

A flow injection method for the assay of perphanazine using cerium(IV) as oxidant in a sulphuric acid media was adopted. Different chemometr ic techniques, considered the main objective of this work, were utilis ed to optimise sensitivity and sample throughput as a function of five experimental variables. The optimum conditions obtained by the super modified simplex method were, 0.170 M sulphuric acid, 2.13 mM cerium(I V), 2.56 ml min(-1) flow rate, 52 cm coil length, and 136 mu l sample loop size. A central composite design was successfully employed, chara cterising the relation between these variables and the response surfac e. and hence validating the optimum conditions obtained by the simplex method. Regression analysis of the data from the experimental design, demonstration that a second order polynomial model is an adequate des cription of the surface over the factor limits studied. Further analys is of the response surface revealed the presence of a broad maximum ar ound the simplex method optimum. A linear calibration curve in the ran ge 50-500 ppm together with a sampling frequency of at least 120 s h(- 1) and a relative standard deviation of less than 0.8% were obtained f or the determination of perphenazine in its purl analytical grade. Res ults of the perphenazine assay in pharmaceutical preparations indicate s that the method does not suffer interference from excipients renderi ng the method suitable for the assay of perphenazine in drug formulati ons. (C) 1998 Elsevier Science B.V. All rights reserved.