Determination of Calcium and Magnesium in High Purity Sodium Chloride by Atomic Absorption Spectrometry Combined with 1-Phenyl-3-Methy1-4-Benzoy1-5-Pyrazolone Extraction
1988 Volume 42 Issue 2 Pages 59-62
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1988 Volume 42 Issue 2 Pages 59-62
Trace amount of calcium and magnesium in high purity sodium chloride was determined b atomic absorption spectrometry combined with 1-pheny1-3-methyl-4-benzoy1-5-pyrazolone (PMBP)-MIBK extraction. The optimum conditions for the extraction of calcium and magnesium were examined. The procedure was as follows: About 40 g of the salt sample was dissolved in water and diluted to 200 ml. Twenty ml of the sample solution was pipetted into a 100 ml separating funnel. Ten ml of NH3-NH4Cl buffer solution (pH 9), which had been purified by two extractions with PMBP-MIBK solution, was added. Then 10 ml of 0.02 M PMBP-MIBK solution was added and the two phases were shaken for 5 min to extract calcium and magnesium to the MIBK phase. The separated organic layer was analyzed by atomic absorption spectrometry.
The relative standard deviation of four repeated analyses of sodium chloride was 4.1-5.9% for calcium and 1.4-8.3% for magnesium, respectively. The recoveries of calcium and magnesium added to sodium chloride samples were excellent.
