In-line Membrane Extraction-IC Determination of Inorganic Anions in n-Butyl Acetate

Inorganic anions (including Cl-, NO2-, Br-, and NO3-) in sample of n-butyl acetate was extracted by de-ionized water, passing through the hollow fibre membrane, and determined by IC. Optimized conditions were given as follows: ① rate of agitation: 450 r·min-1; ② flow-rate of extraction: 30 μL·min-1; ③ time of extraction: 30 min. When operated under the optimum conditions, linear relationships between values of response signals and mass concentration of the 4 anions were obtained in definite ranges and detection limits (3S/N) found for the 4 anions were 0.002, 0.006, 0.100, 0.004 mg·L-1 respectively. Mixed solutions containing 1.00 mg·L-1 for each of Cl- and Br-, and 0.20 mg·L-1 for each of NO2- and NO3- were analyzed by the proposed method to test for precision, values of RSD′s (n=6) found were 6.4%, 7.9%, 12% and 7.4% respectively. A sample of pure n-butyl acetate was analyzed by this method and recovery was tested by standard addition method, giving results of average recovery of 89%, 115%, 115% and 103% for Cl-, NO3-, Br- and NO3- respectively.