镉柱还原光度法测定海水中的硝酸盐氮

Detection of nitrate nitrogen in seawater with cadmium column and spectrophotometry

将纯镉柱还原法与流动注射技术和分光光度法相结合,建立了一种快速测定海水样品中硝酸盐氮含量的方法。用粒径为2～5 mm的镉粒填装有效柱长为10 cm的镉柱,在停留时间为480 s,温度为20～35℃,pH2.5～3.0条件下,还原效率可稳定在95%以上,且测定结果不受海水中主要共存离子的影响。方法对硝酸盐氮的测定范围为0～20.0μg/mL,检出限为0.015μg/mL。对实际海水样品中的硝酸盐氮含量进行测定,相对标准偏差≤1.5%,平均加标回收率≤104%。

Nitrate nitrogen is one of the main pollutions which lead to eutrophication in seawater.So it＇s quite important to monitor the concentration of the nitrate nitrogen in seawater quickly and effectively.Using a column filled with pure cadmium,cooperating with FIA and spectrophotometry,a method to determine the nitrate nitrogen in seawater was established.As result,when the diameters of cadmium particles are 2~5 mm,the length of the cadmium column is 10 cm,the residence time is 480 s,the reduction temperature is 20 ℃~35 ℃,and pH is 2.5 to 3.0,the percent reduction can be stabilized at more than 95%.The result is not infected by the coexisting ions in seawater.The measurement range of this method is 0~20.0 μg/mL,and the detection limit is 0.015 μg/mL.The concentration of the nitrate nitrogen in real seawater samples was detected with the method.The RSD is less than 1.5%,and the average recovery is 101.6%.Compared with national standard,the results are similar to each other.