Round robin tests for the anion determination of atmospheric particulate matters and rainwater by ion chromatography

A study on interlaboratory comparison was undertaken by request from the Air Quality Bureau of Environment Agency, Japan, and the analytical reliability of ion chromatography by round robin tests and the comparison with the results by the conventional colorimetric or nephelometric methods were investigated. Choosing NO3- and SO42- as the ions to be measured, using some standard solution and extract solution of atmospheric particulate matters and rainwater. The results by ion chromatography showed with well reproducibility and accuracy by using the same instrument and at the same laboratory, and the agreement of the interlaboratory was also good. In comparison with the results by ion chromatography and the conventional method, a good agreement was obtained for ion concentrations of (10100)μg ml-1 and was not so well for ion concentrations below a few μg ml-1 level. The good agreement and high precision were obtained for ion chromatography, but the poor agreement and precision were observed for the conventional method. It was demonstrated from these results that ion chromatography can be employed as a standard method to be an excellent analytical method for ions in atmospheric samples.