摘要
利用紫外分光光度计研究了紫外分光光度法测定硝酸盐过程中亚硝酸盐存在对测定结果的影响。结果表明,若按照标准方法测定硝酸盐水样,测定出的硝酸盐浓度相对误差将随着亚硝酸盐浓度的升高而逐渐增大,亚硝酸盐的存在会对硝酸盐的测定值产生正偏离。当水样中硝酸盐浓度达到100×10-6时,测得硝酸盐浓度为配制浓度的3倍多,相对误差达到230.5%。虽然将掩蔽剂浓度增大到标准方法的10倍时能够更多地掩蔽亚硝酸。但是当水样中亚硝酸盐浓度大于60×10-6时,仍会因掩蔽剂量不足导致相对误差再次增加。同时,过度增加掩蔽浓度会影响吸光度,从而影响测定结果准确性。建议当水样中亚硝酸盐浓度大于60×10-6时采用离子色谱法更为准确。
The effect of nitrite in analysis of nitrate by using method of UV spectrophotometry was studied. The results showed that the positive deviation will produced in nitrate determination with nitrite exists and the relative error of nitrate determination will gradually increase with nitrite concentration increasing in water samples, by the standard method. The measured value of nitrate was more than 3 times theoretical concentration, relative error is 230. 5%, when nitrate concentration at the 100 × 10^-6 in water samples. The nitrite could well mask when the masking agent eoncentration increased to 10 times comparing with the standard method. But when nitrite concentration was greater than 60 × 10^-6 in water, the relative error of nitrate determination will produced again, because of lacking of masking agent. At the same time, the excessive increase of masking concentration will affect the measurement of absorbance. So, we suggested to choose ion chromate-graphy is more accurate when nitrite concentration was greater than 60 × 10^-6 in water.
出处
《实验室研究与探索》
CAS
北大核心
2014年第11期10-14,共5页
Research and Exploration In Laboratory
基金
国家自然科学基金项目(No.51008202)
江苏省环保厅重大项目(No.201104)
江苏省高等教育教改研究项目(2011JSJG249)
