AN ION-EXCHANGE ATOMIC-ABSORPTION METHOD FOR THE DETERMINATION OF IONIZED CALCIUM AT MILLIMOLAR LEVELS

被引：2

作者：

HEWAVITHARANA, AK ^{[1
]}

MUTUCUMARANA, V ^{[1
]}

KRATOCHVIL, B ^{[1
]}

机构：

[1] UNIV ALBERTA,DEPT CHEM,EDMONTON T6G 2G2,ALBERTA,CANADA

来源：

CANADIAN JOURNAL OF CHEMISTRY-REVUE CANADIENNE DE CHIMIE | 1991年 / 69卷 / 12期

关键词：

ION EXCHANGE; ATOMIC ABSORPTION; FREE CALCIUM DETERMINATION; ION SPECIATION;

D O I：

10.1139/v91-284

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

A quantitative ion exchange/atomic absorption method is described for measuring the fraction of free calcium in solution at millimolar levels. Sample solutions are equilibrated with a micro-column of strong-acid type cation-exchange resin under electrolyte concentrations (0.75 mol/L NaNO3) high enough to provide conditions where the calcium sorbed on the resin is proportional to the free calcium in solution. After a water wash, the sorbed calcium is eluted from the resin with nitric acid directly into an atomic absorption spectrophotometer. Free calcium levels were estimated using calibration curves obtained over the range 0-5 mM calcium with a precision of +/- 0.05 mM. The effect of magnesium, at concentrations twice that of calcium, on measured calcium levels is negligible. The method is pH insensitive over the range 5-7. Selectivity for free calcium in the presence of complexing ligands such as citrate and phosphate is high. The method shows promise for the determination of ionized calcium in biological systems.

引用

页码：1976 / 1979

页数：4

共 19 条

[1] FREE NICKEL ION CONCENTRATION IN SEWAGE BY AN ION-EXCHANGE COLUMN-EQUILIBRATION METHOD [J].

CANTWELL, FF ;

NIELSEN, JS ;

HRUDEY, SE .

ANALYTICAL CHEMISTRY, 1982, 54 (09) :1498-1503

[2] SEMIAUTOMATED METHOD FOR ESTIMATION OF IONIC CALCIUM ACTIVITY AND CONCENTRATION IN BIOLOGICAL SOLUTIONS [J].

CHAM, BE .

CLINICA CHIMICA ACTA, 1972, 37 (NMAR) :5-&

[3] THE FORMATION OF PROTON AND ALKALI-METAL COMPLEXES WITH LIGANDS OF BIOLOGICAL INTEREST IN AQUEOUS-SOLUTION - POTENTIOMETRIC AND PMR INVESTIGATION OF LI+, NA+, K+, RB+, CS+ AND NH4+ COMPLEXES WITH CITRATE [J].

CUCINOTTA, V ;

DANIELE, PG ;

RIGANO, C ;

SAMMARTANO, S .

INORGANICA CHIMICA ACTA-BIOINORGANIC CHEMISTRY, 1981, 56 (02) :L45-L47

[4]

DANIELE PG, 1983, ANN CHIM-ROME, V73, P495

[5]

ESTHAM RD, 1978, BIOCH VALUES CLIN ME

[6]

FLEISH H, 1976, UROLITHIASIS RES

[7]

HELFFERICH F, 1962, ION EXCHANGE, P169

[8]

Helffrich F., 1962, ION EXCHANGE, P230

[9] VARIABILITY OF IONIZED CALCIUM WITH PH OF NORMAL URINE [J].

JACOBSON, AL ;

SINGHAL, PC ;

MANDIN, H ;

HYNE, JB .

BIOCHEMICAL MEDICINE, 1979, 22 (03) :383-386

[10]

Martell A.E., 1977, CRITICAL STABILITY C, V3

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