Capillary electrophoresis with capacitively coupled contactless conductivity detection for low molecular weight organic acids in different samples

CE with capacitively coupled contactless conductivity detection (CE-C⁴D) was explored and validated for the identification and quantification of organic acids in various types of samples. The analyses were performed under optimized conditions, using a buffer system composed of 20 mM MES-histidine (His), pH 6.0, 0.1 mM CTAB, 0.025% HP-β-CD, and 10% methanol. The investigation included a study of the effects of buffer pH, concentration of CTAB, type and concentration of organic additives, on the migration behavior, resolution and selectivity of the organic acids. The intra- and interday RSDs (n = 6) obtained for migration time and peak area were typically in the range of 0.12-2% and 0.5-4%, respectively. Linearity, detection limits, and repeatability were evaluated. In order to evaluate the application potential of the developed method, real samples from different sources were analyzed. The results demonstrate that CE-C⁴D is a versatile tool for analyzing organic acids in beverages, Chinese herbal medicines (CHM) and plants as it allows for their detection, identification, and quantification.