Abstract: A simple and inexpensive flow injection-capillary electrophoresis (FI-CE) system with contactless conductivity detection (CCD) for automated quantitative analysis of chloride, nitrate, and sulfate in various water samples is demonstrated. A glass bottle containing the background electrolyte that is raised above the FI-CE interface generates a pulse-free, highly reproducible flow of the electrolyte through the FI-CE interface. The system operates at a flow rate of 300 Lmin-1 with an injection volume of only 4 L. The repeatability of peak areas (n = 18) was better than 0.81% RSD and the sample throughput was 90 samples per hour using the background electrolyte containing 12 mM L-histidine adjusted to pH 4.00 with acetic acid. The limits of detection were better than 125 gL-1 and were comparable to those obtained by conventional CE systems with CCD. Various calibration methods for FI-CE system with electrokinetic injection were tested and their suitability for the analysis of anions in real samples was evaluated.

Abstract: A flow injection-capillary electrophoresis system with contactless conductivity detection and hydrostatic-pressure-generated flow was used for the fast and sensitive speciation of Se(IV) and Se(VI). The sample throughput was 25 samples per hour using a background electrolyte solution containing 8.75 mM l-histidine (His) adjusted to pH 4.00 with acetic acid. The repeatability of peak areas (n=8) was better than 1.41% and the limits of detection were 190 µg L-1 and 7.5 µg L-1 for Se(IV) and Se(VI), respectively. The interference from carbonate, typically present in water samples, was eliminated by using a low-pH electrolyte in which carbonate is uncharged and migrates at the EOF front. The method was applied to the analysis of Se(IV) and Se(VI) in soil samples that were spiked with both selenium species and the results for recovery of both selenium species were in good agreement with their introduced concentrations.