Simultaneous Determination of Sulfamethoxazole and Phthalazine by HPLC and Multivariate Calibration Methods

Two multivariate calibration methods are compared for the simultaneous chromatographic determination and separation of Sulfamethoxazole (SMX) and Phthalazine (PHZ) by High Performance Liquid Chromatography (HPLC). Multivariate calibration techniques such as Classical Least Squares (CLS) and Inverse Least Squares (ILS) were introduced into HPLC to determine the quantification by using UV detector at 235, 250, 260 and 270 nm. Sixteen binary mixtures of SMX and PHZ as calibration set and eight binary mixtures as prediction set were used. Results show that, Relative Errors of Prediction (REP) of CLS and ILS for SMX and PHZ were 0.17%, 0.63% and 0.15%, 0.56%, respectively.