含泥沙的地表水总氮测定准确度的提高方法

针对碱性过硫酸钾消解紫外分光光度法测定含泥沙的地表水中总氮时,数据准确度常受到絮凝沉淀的干扰的问题,采用一次性0.45μm水相针式滤器过滤消解后水样,快速有效地去除絮凝沉淀的干扰,达到了提高含泥沙的地表水总氮测定准确度的目的。结果表明,该方法相对标准偏差2.0%,加标回收率为92.0%~96.5%,符合实验室质控要求。

A Method of Improving the Accuracy in the Determination of Total Nitrogen in Surface Water Containing Sediments

In determination of total nitrogen in surface water containing sediments using the alkaline potassium persulfate digestion -UV spectrophotometry,data accuracy is often influenced by insoluble floc .In this study,the digested sample was filtered through a 0.45 μm aqueous needle filter,which quickly and efficiently removed the insoluble floc and improved the accuracy of total nitrogen determination.Experimental results showed that using this method ,the RSD was below 2.0% and the recoveries were in the range of 92.0 % ~96.5 %,which met the laboratory quality control requirements .