A Critical Study on the Methods of Water Analysis. (IX)

[摘要] Even in the present times, a micro chemical determination of nitrate is not an easy problem. Almost all of the methods now usually adopted, have many difficulties on the preparations of reagents and the analytical processes. A chief and common demerit of these methods is a necessity of a largequantity of concentrated sulphuric acid. Sulpuhric acid, completely free from even a minute quantity of nitrate, is too expensive to use it for daily routine works.The present autbor has prepared a next new reagent for this purpose.α-Naphtyl amine 1g.Sulphanylic acid 10g.Tartaric acid 88g.Zink dust 1 to 1.5g.Zink dust reduces nitrate to nitrite, and then the pink colour due to nitrite appears. Nitrite formerly present must be removed. There are two methods for the elimination of nitrite; the one is an oxydation with bromine, and the other is a destruction of it with sodium azide in an acidic solution.

[学科分类] 大气科学