Estimation of metal impurities in high-purity nitric acids used for metal analysis by inductively coupled plasma-mass spectrometry.

A simple method to estimate the amounts of ultra-trace metal impurities in nitric acid reagents has been developed. The determination of sixty-four metals in nitric acid was accomplished by direct measurements of 0.1 M nitric acids accurately diluted with ultrapure water by ICP-MS. Though accurate metal concentration could not be obtained for all of the elements, we could effectively evaluate the nitric acid quality by comparing the ion counts of the samples, ultrapure water and standard metal solutions for a calibration prepared with Ultrapur nitric acid.