Abstract
The interference of the twenty-four water-soluble organic compounds in atomic absorption spectrophotometry of calcium in an air-acetylene flame was studied.
A Nippon Jarrell-Ash model AA-1 atomic absorption/flame emission spectrophotometer and a slit burner (slit width 0.5×100mm) were used. A hollow cathode lamp of calcium(Westinghouse) was used as a source of radiation.
The interference of the water-soluble organic compounds on calcium were observed the concentration in the order of 100 ppm. Such interferences were found to be greatly different from each other depending on the concentrations and on the types of the compounds.
Some examples of these interferences caused by the water-soluble organic compounds were as follows and their values were expressed by the relative absorbance.
Glucose: 1.22, Ascorbic acid: 1.24, EDTA: 1.82, Ethylene glycol: 1.49, Ethanolamine: 1.38, Pyruvic acid: 1.31, Tartaric acid: 0.85, Glycolic acid: 0.88.
The method of controlling the interference caused by the water-soluble organic compounds was studied by an addition of a compound which yields an intensive enhancement interference on calcium.
As the results, it was found that ammonium perchlorate gave an intensive enhancement interference on calcium. The interference of ammonium perchlorate was stronger than that of the water-soluble organic compounds. Accordingly, the interference of the water-soluble organic compounds on calcium can be controlled by an addition of ammonium perchlorate.
The exact quantitative analysis of calcium containing some water-soluble organic compounds was made by atomic absorption spectrophotometry in an air-acetylene flame, provided that the ammonium perchlorate was added in the sample solution and standard solution of calcium in equal concentration.
