TM93-01 Identification of Low Levels of Sodium Contamination in Nitric Acid Samples

For several years the nitric acid ampules have been tested using the regular level ICP or AA methods and previously approved nitric acid ampules as control materials. The quality acceptance of nitric acid ampules was based on consistency of preparation. The contract with the current ampule supplier requires sodium contamination to be no more than 0.5 mg/L. The ampules have routinely and easily met the contract specification, and the detection limits of the AA and ICP methods of 0.1 and 0.2 mg/L, respectively. For review, the NWQL determines sodium in water samples supplied in white polyethylene bottles by the following methods: