The simultaneous determination of inorganic anions using an ion chromatographic method comparisons with colorimetric assays

Even at present there are few experiments dealing with the levels of inorganic anions present in human serum; only chloride and phosphate are determined routinely. The fact that much less attention has been paid to other anions is due to a lack of rapid or convenient analytical methods. A suitable, though novel, method for the determination of anions is ion chromatography. After an appropriate dilution, the sample is directly injected into the ion chromatography without further pretreatment and plural anions are determined simultaneously. In this paper, the authors report on ion chromatography measurements; i.e., on (1) the accuracies of measurements, (2) comparisons with colorimetric assays, and (3) an approach to the quantitative analysis of inorganic anions present in human serum. Standard solutions including equal amounts of 7 anion species fluoride, chloride, nitrite, phophate, bromid, nitrate, and sulphate, were made. These anions were accurately measured simultaneously, ranging from about 100 mg/l to 0.1 mg/l. Using river and hot spring water in Oita prefecture, good results were obtained from a comparative study of traditional colorimetric assays and the ion chromatographic methods. The concentrations of phosphate, bromide, nitrate, and sulphate in a standard human serum were determined and these agreed with the values found by other methods. The ion chromatographic method is a rapid and reliable technique for the simultaneous determination of these anions in a small volume of serum. At present the authors are engaged in investigating the effects of various diseases on the levels of the inorganic anions.