1.1 This test method is applicable for the analysis total nitrogen (organic nitrogen + ammonia-N + nitrate-N + nitrite-N) as nitrate and total phosphorus as orthophosphate in unfiltered water samples by alkaline persulfate digestion followed by ion chromatography. 1.2 Total Kjeldahl nitrogen (TKN) is determined by the calculation. To determine TKN subtract the nitrate-N and nitrite-N in a digested sample from a non-digested sample. 1.2 The LOD, LOQ, and reporting range below are based on the two-step process for this test method-digestion and analytical step. Because the digestion step requires a sample dilution, the LOD and LOQ are higher than undigested samples. The reporting range, LOD, and LOQ can be modified and perhaps improved depending on several factors. 1.3 The digestion reagent contains background nitrate and results in higher detection limits. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
This standard is needed because it is a new, direct injection technique for the simultaneous determination of total nitrogen and total phosphorous.
Keywordsion chromatography; alkaline persulfate digestion; total nitrogen; total phosphate; nitrate; phosphate; ortho-phosphate; total Kjeldahl nitrogen
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
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