小体系连续快速批量测定淡水亚硝酸盐氮分光光度法

Continuous and Rapid Batch Determination of Nitrite Nitrogen in Fresh Water by Small System Spectrophotometry

亚硝酸盐氮(NO^(-)_(2)-N)是水体中的含氮有机物被氧化转变为硝酸盐反应过程中的中间产物,水环境中存在的NO^(-)_(2)-N具有毒性与致癌性,因此,NO^(-)_(2)-N含量的准确快速测定具有非常重要的意义。用酶标仪代替传统的紫外分光光度计,以2 mL离心管为反应容器进行NO^(-)_(2)-N含量的测定,优化小体系测定NO^(-)_(2)-N含量的关键影响因素,即反应体系的体积、显色时间、显色剂用量,研究结果表明:小体系反应总体积1 mL、显色剂用量20μL、显色时间20 min、pH范围7~9,NO^(-)_(2)-N质量浓度为0~0.6 mg/L标准曲线的线性良好(r>0.999)。根据小体系与国标体系测定的结果进行线性拟合和正交验证,结合2种方法的差异显著性分析,证明了小体系测定NO^(-)_(2)-N含量新方法的准确性与可靠性。

Nitrite nitrogen(NO^(-)_(2)-N)is the intermediate product of the oxidation of nitrogen-containing organic matter in water that finally transformed into nitrate reaction.NO^(-)_(2)-N existed in water environment possesses toxicity and carcinogenicity.Therefore,the accurate and rapid determination of NO^(-)_(2)-N content is of great significance.In this study,enzyme labeling instrument was used to replace the traditional ultraviolet spectrophotometer,and the 2 mL centrifugal tube was used as the reaction vessel to determine the content of NO^(-)_(2)-N.The key factors that affected the determination of NO^(-)_(2)-N were optimized in the small system.The results showed that the total reaction volume of the small system was 1 mL,with the amount of developer 20μL,the color development time 20 min,the pH range 7-9,and the linearity of standard curve was good when the NO^(-)_(2)-N concentration range was between 0-0.6 mg/L(r>0.999).Linear fitting and orthogonal verification were carried out according to the determination results of the small system and national standard system.Moreover,the significant difference between the two methods was also analyzed,which further proved the accuracy and reliability of the new method for determining the NO^(-)_(2)-N content with small system.