Abstract: A novel method for the separation and determination of o-phthalaldehyde (OPA), p-chloro-m-xylenol (PCMX) and triclosan in daily chemicals and compound chemical disinfectants in a single run by micellar electrokinetic chromatography (MEKC) was established. The factors such as the buffer concentration and pH, the concentration of sodium dodecyl sulfate (SDS), and the sample buffer, were investigated in detail. The analysis was carried out using a 50 μm uncoated capillary of 40.2 cm in total length (effective length: 30 cm). The running buffer was 20 mmol/L Na2B4O7 and 80 mmol/L SDS. The sample buffer was 2 mmol/L Na2B4O7-8 mmol/L SDS (without pH adjustment) containing 10% (v/v) methanol. The detection wavelength was 214 nm. The relative standard deviations (RSDs) of the corrected peak areas of the three components were in the range of 1.1%-3.8%, and the RSDs of migration times were less than 0.9%. The limits of detection (LODs, S/N=3) were 4.0, 0.4 and 0.4 mg/L, and the limits of quantification (LOQs, S/N=10) were 12, 1.2, and 1.2 mg/L for OPA, PCMX and triclosan, respectively. The corrected peak areas and the concentrations of the three components showed good linear relationship within the ranges of 12-2 000 mg/L, 1.2-200 mg/L and 1.2-200 mg/L with the correlation coefficients of 0.9994, 0.9993 and 0.9995 for OPA, PCMX and triclosan, respectively. The method was used for the determination of the three components in compound chemical disinfectants, hand washing liquids, soaps and a toothpaste. The results showed that the three components could be assayed in a single run with simple sample pretreatment, rapidity, accuracy and low cost, and the method is convenient for routine analysis.

Key words: bactericides, daily chemical, disinfectant, o-phthalaldehyde (OPA), p-chloro-m-xylenol (PCMX), triclosan, micellar electrokinetic chromatography (MEKC)