Monitoring Chloride and Nitrite Ions in 2,4-Dichlorofluorobenzene Plant Effluent by CE

A capillary electrophoresis method was developed for the separation and determination of chloride and nitrite in the effluents obtained during the process development of the synthesis of 2,4-dichlorofluorobenzene. Monitoring chloride and nitrite in the process effluents is necessary to improve the yield, minimize the formation of undesirable compounds and also to reduce environmental pollution. A buffer consisting of boric acid, chromate and tetradecyltrimethylammonium bromide was used for the separation. Nitrate was used as the internal standard. Indirect UV detection was performed at 254 nm using chromate co-ion as a chromophore. The limit of detection of chloride and nitrite were 0.85 and 1.05 ppm, respectively. The intra- and inter-day variance values were less than 3% with correlation coefficients for the two target anions of >0.999. The recoveries for chloride and nitrite ranged from 99.24% to 101.56%. Chlorides and nitrites in the process samples were in the range of 0.08–0.16% and 0.18–0.28%, respectively. There was no interference from other peaks under the optimized electrophoretic conditions.