Atomic Absorption Spectrometry of Calcium in Sea Water by Using a Strontium Carbonate Coprecipitation Method

Studies on Environmental Analysis (Part 39)

Abstract

Determination of calcium was studied by a coprecipitation method with a strontium carbonate andthe subsequent atomic absorption spectrometry (AAS).
Fifteen milliliters of 2 g Sr/l strontium chloride and 15 ml of 20 w/v 70 potassium carbonate wereadded to sample water, which was then stirred for 30 min. After collecting the precipitate containingcalcium on a membrane filter, the precipitate was dissolved with 2 ml of (1+12) HNO₃, andwas used for AAS. The linear range of calibration curve was from 10 to 1,000 μg/l, and the limitof detection and the lower limit of determination were found to be 1.5 and 5.1 μg/l, respectively.This method was not influenced by sample size from 100 to 1,000 ml, and was satisfactorily appliedto determine calcium ions in environmental water without any interfering effects of the copresentions.
The values obtained from the calibration curve method agreed with those from the standard addition method.