Rapid determination of magnesium and calcium in water and serum by ion chromatography

Technical Report · Sat Aug 01 04:00:00 EDT 1987

OSTI ID:6182460

Smith, D L

Single column ion chromatography was used to separate calcium and magnesium on poly(styrene-divinylbenzene) sulfonated to a capacity of 9 ..mu..eq/g. A 0.12 M HClO/sub 4/ eluent was used. The ions were complexed with Arsenazo I, at pH 10, in a post column reactor. The complexes were monitored spectrophotometrically at 590 nm. The separation of these ions is achieved in under three minutes. The method is rapid, reproducible, accurate and relatively free of interferences. A variety of water samples were analyzed and results agreed to within 10% with those obtained from an EDTA titration. Serum samples were analyzed for the total and ionized fractions of calcium and magnesium. For the total ion concentration, the serum was acidified, centrifuged and the liquid layer was injected into the chromatograph. The ionized forms of calcium and magnesium were separated, from the protein matrix, on a ''mini'' column filled with 0.07 g of XAD-4 resin sulfonated to a capacity of 2.8 meq/g. The ions were eluted from the ''mini'' 4 column with 4 M HCl, the mixture was buffered to pH 10 and injected into the chromatograph. A flow rate of 35 mL/min was required to push the serum sample through the ''mini'' column to prevent the equilibria of the bound fractions of calcium and magnesium from shifting.

• Research Organization: Ames Lab., IA (USA)
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 6182460
• Report Number(s): IS-T-1318; ON: DE87013601
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102* -- Chemical & Spectral Procedures
ALKALINE EARTH METALS
BLOOD SERUM
CALCIUM
CHEMICAL ANALYSIS
CHROMATOGRAPHY
ELEMENTS
HYDROGEN COMPOUNDS
ION EXCHANGE
MAGNESIUM
METALS
ORGANIC COMPOUNDS
ORGANIC POLYMERS
OXYGEN COMPOUNDS
PETROCHEMICALS
PETROLEUM PRODUCTS
POLYMERS
QUANTITATIVE CHEMICAL ANALYSIS
RESINS
SEPARATION PROCESSES
WATER