夹管电磁阀定量-流动注射分析系统测定海水中亚硝酸盐和硝酸盐氮

Determination of Nitrite and Nitrate-Nitrogen in Seawater by Flow Injection Analysis Based on Quantificational Pipe Clamp Solenoid Valves

采用3个夹管电磁阀联用代替传统六通阀的样品定量方法,自制一套多通道流动注射分析仪,并优化了仪器的最佳测试条件,实现了海水中硝酸盐氮和亚硝酸盐氮含量的测定。本分析系统结构简单,性能可靠,测定频率为28个/h。测试结果表明,亚硝酸盐氮和硝酸盐氮的线性范围(以氮含量计)分别为25～1000μg/L和50～1000μg/L(R≥0.999),检出限分别为1.8和4.8μg/L;加标回收率在94.5%～105.3%之间;加标200.0μg/L的回收实验的相对标准差在1.3%～4.5%之间(n=6)。经t检验分析,本方法与国标方法测定数据无显著性差异,可适用于海水中微量亚硝酸盐氮和硝酸盐中氮的快速测定分析。

Using three pipe clamp solenoid valves to replace the traditional six-port valve for sample quota,a set of multichannel flow injection analyzer was designed for the determination of nitrate and nitrite in seawaters.The construction of apparatus is simple and has potential to be used for analysis of nitrite and nitrate.The sample throughput of nitrite and nitrate was 28 samples/h.The liner range of nitrite and nitrate was 25.0-1000 μg/L and 50.0-1000 μg/L(R≥0.999).The detection limits of nitrite and nitrate were 1.81 μg/L and 4.82 μg/L.The recovery of nitrate and nitrite was 94.5%-105.3%.The relative standard deviations for 200 μg/L of nitrate and nitrite was 1.3%-4.5%(n = 6).The results showed that there are not significance differences between this method and national standard method in the t-test analysis.The method is suitable for fast analysis of nitrite and nitrate in seawater.