Sequential Injection Chromatography with Monolithic Column for Phenothiazines Assay in Human Urine and Pharmaceutical Formulations

Background: Sequential injection chromatography (SIC) with monolithic column has been proposed with potential benefits for separation and quantification. Objective: To utilize SIC to develop a new assay method for the separation and quantification of some phenothiazines (promethazine, chlorpromazine and perphenazine) in human urine and synthetic pharmaceutical formulations. Methods: The 3(2) full-factorial design was adopted to study the effect of mobile phase composition on separation efficiency, retention time, peak height and baseline. The separation was conducted on a C-18 monolithic column (100 x 4.6 mm) using a mobile phase composition of phosphate:acetonitrile:methanol (60:28:12) at pH 4.0. The detection was carried out using a miniaturized fiber optic spectrometer at 250 nm. Results: Satisfactory analytical features, including number of theoretical plates (1809-6232), peak symmetry (1.0-1.3), recovery (95.5-99.1% in pharmaceutical formulations and 91.6-94.7% in urine), intra-day precision (0.36-1.60% for pharmaceutical formulation and 2.96-3.67 for urine), inter-day precision (1.47-2.28% for pharmaceutical formulation), limits of detection (0.23-0.88 mu g/ml) and limits of quantification (0.77-2.90 mu g/ml), were obtained. Conclusion: The remarkable advantages of the proposed SIC method are the inexpensiveness in terms of instrumentation and reagent consumption.