氨氮测定水样絮凝预处理方法的改进

Improvement of Flocculation Pretreatment Method for Determination of Ammonia Nitrogen in Water Samples

对纳氏试剂光度法测定氨氮的水样絮凝预处理方法进行了改进,水样取样量和所加入的显色剂减少一半,絮凝时水样p H调节约为6.5。改进后方法检出限<0.025mg/L,连续配制五天的校准曲线无显著性差异,试验样品均在其质控范围内。同时用改进法对水样进行测定,样品精密度及准确度均能达到质控要求。此方法既准确可靠,又方便快捷。

An improvement has been provided to the flocculation pretreatment of ammonia-nitrogen determination in water by the method of Nessler′s reagent photometry. The dosage of the water sampling and chromogenic agent has been reduced by half while the p H of the water was adjusted around 6.5. The detection limit was lower than 0.025mg/L. There was no significant difference in five days continuous preparation of calibration curve and the determination of the standard specimen was also within the scope of quality control. The precision and accuracy of the ammonia-nitrogen determination in water were satisfactory and completely meet the request of quality control by using the improved method. This improved method was accurate,reliable and more convenient.