Quantitative determination of paracetamol, caffeine and codeine in pharmaceautic tablets by capillary electrophoresis

A new capillary electrophoresis method has been developed to analyze the pharmaceutical preparations containing ternary combination of paracetamol, caffeine and codeine phosphate. Best results were obtained by using a background electrolyte solution consist of 25 mM pH 8,5 phosphate buffer containing % 10 methanol. The separation was performed through a fused silica capillary (50 ?m internal diameter, 56 cm total length, 47,5 cm effective length) at 25 oC with the application of 10 s of hydrodynamic injection at 40 mbar pressure and a potential of 27 kV. Detection wavelength was 210 nm. Under these conditions, the migration times were found to be 4,427 min for paracetamol, 3,952 min for caffeine, and 3,253 min for codeine phosphate. Linearity ranges for the method were determined as 99,72 ? 1994,40 ?gmL-1 for paracetamol, 5,75 ? 115,04 ?gmL-1 for caffeine and 1,84 ? 36,80 ?gmL-1 for codeine phosphate. Limit of detections were found as 0,724 ?gmL-1 for paracetamol, 0,533 ?gmL-1 for caffeine and 0,263 ?gmL-1 for codeine phosphate. Limit of quantitations were found as 2,415 ?gmL-1 for paracetamol, 1,776 ?gmL-1 for caffeine and 0,877 ?gmL-1 for codeine phosphate. According to the obtained results, the method is sensitive, specific and repeatable.