NEN 6646-1990
水.通过连续流动分析光度分析法测定铵态氮的含量以及氨态氮和有机态氮的总含量(凯氏法)
Water - Photometric determination of the content of ammonium nitrogen and of the sum of the contents of ammoniacal and organically bound nitrogen according to Kjeldahl by continuous flow analysis