Determination of Chloride and Sulfate in Lithium Carbonate by Ion Chromatography

Sample of lithium carbonate (0.500 g) was dissolved in some water, and made up its volume to 100 mL with water. An aliquot of 10.00 mL of the sample solution was taken for IC separation of Cl^- and SO₄^2- ions without removing the matrix carbonate. The anion exchange column Dionex IonPac AS11 was used for separation at column temperature of 30 ℃ and 15 mmol·L^-1 KOH solution produced by a KOH eluant generator was used as the mobile phase, with flow-rate of 1.0 mL·min^-1. Linearity ranges for Cl^- and SO₄^2- were within 16.0, 3.2 mg·L^-1, with values of detection limits (3s/k) of 0.004, 0.01 mg·L^-1, respectively. Test for precision was made with a same sample, giving values of RSDs (n=6) less than 2.7%. Test for recovery was made by standard addition method, giving results in the range of 93.8%-106%. As shown by the results of analysis of substantial samples, consistent values were obtained as compared with those found by electrochemical method and ion chromatography with on-line matrix removing.