重氮偶联法测定水中亚硝酸盐氮的改进

重氮偶联法作为测定亚硝酸盐氮的标准方法,因具有方法灵敏、选择性强、仪器较易获得等优点,被实验室广泛采用,但也存在测定上限较低,适用样品范围较窄等缺点。通过将显色剂中磷酸改为盐酸,把重氮试剂含量提高到国标法的3倍,明显提高亚硝酸盐氮的测定上限,即由原国标法上限的0.2 mg/L提高到0.6 mg/L,灵敏度与国标法接近,且准确度和精密度良好,6组标准溶液平行测定的相对误差为1.60%,相对标准偏差为1.34%,加标回收率为96.5%~104.9%,适用于生活污水、工业废水、地表水、养殖废水等水体的测定。

Improvement of Diazo-Coupling Method for the Determination of Nitrite Nitrogen in Water

Diazo-Coupling method is widely used to determine nitrite nitrogen in laboratory with the characteristics of sensitive, selective and the instrument easy to obtain. But it has lower upper limit and narrow applicable sample range. By changing the phosphoric to hydrochliric acid in the color development reagent and increasing the diazonium reagent to three times of the national standard method, the upper limit of nitrite determination can be significantly improved. Namely, the 0.2 mg/L of the upper limit of the GB standard curve increase to 0.6 mg/L. The sensitivity of the improved method is approximate to that of the national standard method, in addition, its accuracy and precision are good. The relative error and the relative standard deviation of the six groups of parallel determination of standard solution is 1.6% and 1.34%, respectively. The recovery rate is between 96.5%-104.9%, which is applicable for the determination of nitrite in domestic sewage, industrial wastewater, surface water and aquaculture wastewater.