DETERMINATION OF LITHIUM ION BY LIQUID-PHASE DIAPHRAGM GLOW DISCHARGE-ATOMIC EMISSION SPECTROSCOPY

Determination of lithium ion by liquid-phase diaphragm glow discharge atomic emission spectroscopy (LDGD-AES) in aqueous solution is described. The discharge was generated in a rectangular slot on a quartz tube interposed between two submerged graphite electrodes. The effects of applied voltage, pH, and the addition of organic compounds on the determination were examined. It was shown that increasing the applied voltage and adding methanol to the solution increased sensitivity and decreased the limit of detection significantly. Under the optimum conditions of pH 0.5, applied voltage 800V, and in the presence of 0.8% methanol, a limit of detection of 4 mu g/L and a relative standard deviation of 1.3% (n=11) were achieved. The analytical performance of LDGD-AES was compared to the performance of flame atomic absorption spectrometry.