新双波长分光光度法测定水中痕量亚硝酸盐氮

Determination of Trace Nitrite Nitrogen in Water by New Dual-wavelengths Spectrophotometry

摘要:
目的改进测定水中痕量亚硝酸盐氮。

方法在酸性介质中,水中亚硝酸盐氮能与对氨基苯磺酰胺重氮化,再与盐酸萘乙二胺产生偶合反应,生成紫红色的产物,根据紫红色的深浅,利用稳定悬浮液吸光特性,测定水中亚硝酸盐氮的新双波长光度法。

结果在实验条件下,亚硝酸盐氮浓度在0~0.025μg/mL之间存在线性关系(r=0.99996)。测定波长为540 nm和580 nm。方法检出限为0.0005 mg/L。RSD=1.7%。

结论本法用于水中亚硝酸盐氮的测定,灵敏度、精密度均高于盐酸萘乙二胺比色法。

Abstract:
Objective To develop a simple and sensitive method for determination of trace nitrite nitrogen in water samples.

Methods Nitrite nitrogen was determined directly using the Criess diazo-coupling reaction and the formed azo dye was measured at 540 nm and 580 nm in hydrochloric acid medium.

Results Nitrite nitrogen in the linear concentration range of 0-0.025 μg/mL was determined with a detection limit of 0.000 5 μg/mL. r=0.999 96, RSD=1.7%.

Conclusion The method has been applied to the determination of trace nitrite nitrogen in water samples. The possible reaction mechanism was also discussed.