Simultaneous electrochemiluminescence determination of sulpiride and tiapride by capillary electrophoresis with cyclodextrin additives

Sulpiride and tiapride are often used in the treatment of depression, schizophrenia and psychopathology of senescence, gastric or duodenal ulcers and are also partly excreted by kidney. This work developed a simple and sensitive method for their simultaneous monitoring in human urine based on capillary electrophoresis coupled with electrochemiluminescence detection by end-column mode. β-Cyclodextrin (β-CD) was used as an additive to the running buffer to obtain the absolute separation of sulpiride and tiapride. Under optimized conditions the proposed method displayed a linear range from 1.0 × 10−7 to 1.0 × 10−4 M for both sulpiride and tiapride with the correlation coefficients more than 0.995 (n = 6). Their limits of detection were 1.0 × 10−8 M (45 amol) and 1.5 × 10−8 M (68 amol) at a signal to noise ratio of 3, respectively. The relative standard deviations for six determinations of 2.0 μM sulpiride and 3.0 μM tiapride were 1.8 and 2.5%, respectively. For practical application an extract step with ethyl acetate at pH 11 was performed to eliminate the influence of ionic strength in sample. The recoveries of sulpiride and tiapride at different levels in human urine were between 84 and 95%, which showed that the method was valuable in clinical and biochemical laboratories for monitoring sulpiride and tiapride for various purposes.