A flame-photometric method for determining traces of calcium in lithium chloride

Abstract

The determination of calcium in solutions of lithium chloride (1·5 per cent. w/v) containing up to 2 µg per ml of calcium, and up to 1 µg per ml of aluminium has been investigated. The use of different organic solvents has been studied, and the sensitivity of the determination has been increased 3-fold by the use of an aqueous methanol-butanol mixture. It has been shown that the only serious interference effect, that arising from the presence of the aluminium content, can be prevented by the addition of trans-1,2-diaminocyclohexane-NNN′N′-tetra-acetic acid (CDTA). Recoveries from synthetic samples showed no appreciable bias, and replicate results indicated a satisfactory precision, and a sensitivity of about 0·02 µg per ml.