Determination of Potassium,Calcium and Magnesium Present as Impurities in Lithium Phosphate by Ion-Chromatography

Ion-chromatography with depressed conductivity detection was applied to the determination of K,Ca and Mg present as impurities in lithium phosphate.The analysis was carried out on the DX-80 ion-chromatograph and the chromatographic column of Ion Pak CS12A-5 μm was used as cation separation column.2×10-2mol·L-1 methylsulfonic acid solution was used as eluant at a flow-rate of 2 mL·min-1,and K+,Ca2+ and Mg2+ were determined in the eluate.Linear relationships between the peak areas and concentrations of K+,Ca2+ and Mg2+ were obtained with correlation coefficients of 0.999 6,0.999 3 and 0.999 4 respectively,and detection limits of 0.02 mg·L-1 (for K+) and 0.05 mg·L-1 (for Ca2+ and Mg2+) were found.Tests for precision and recovery were performed giving values of RSD′s less than 3%,and values of recovery in the range of 98.1%-100.3%.