Sensitive Determination of Bromate in Water Samples by Capillary Electrophoresis Coupled with Electromembrane Extraction

Electromembrane extraction (EME) as a novel sample preparation technique was firstly applied for the purification and enrichment of bromate (BrO3−) in drinking water prior to capillary zone electrophoresis with capacitively coupled contactless conductivity detection (CZE-C4D). BrO3−, as the primary disinfection by-product of ozonation, could be well separated with the major inorganic anions coexisting in water samples using a 300 mmol L−1 acetic acid solution as the running buffer. Under the optimum conditions, the calibration curve showed good linearity (r2 = 0.996), and the limit of detection was down to 0.12 ng mL−1 with the enrichment factor at 267. The relative standard deviation (RSD) values for peak area and migration time at a spiked concentration of 10 ng mL−1 of bromate were below 8.8 and 2.5 %, respectively. This proposed EME-CZE-C4D method has been successfully applied to analyze bottled drinking water and tap water samples with recoveries in the range of 85~98 %, providing an alternative to the determination of bromate in drinking water.