Determination of p-toluene sulfonic acid in phenol matrix by capillary zone electrophoresis with ultraviolet detection

The p-toluene sulfonic acid (MA) in phenol matrix was separated and determined by capillary electrophoresis with ultraviolet detector. the effect of the concentration and pH of the buffer on separation was investigated. Cinnamic acid has been chosen as the internal standard from four compounds, the calibration curves of PTSA in 50 mg/L phenol matrix were obtained with and without the internal standard. The linear range was from 1.25 to 12.5 mg/L and the correlation coefficient was 0.9999 for both curves. The limit of detection of PISA was 0.75 mg/L at 3 times of SIN. Finally, the concentration of PTSA in four synthesized samples was determined with method of standard additions, and the effect of matrix was discussed. The values of MA in these samples were 1.01, 0.94, 1.56 and 0.00 mg/L respectively.