顺序注射微量注样在线稀释分光光度法测定环境水样中的正磷酸盐

Determination of Phosphate in Environmental Samples by Sequential Injection Micro-sampling On-line Dilution Spectrophotometry

[目的]研究应用顺序注射微量注样在线稀释分光光度法测定环境水样中正磷酸盐的可行性。[方法]运用顺序注射微量注样智能化在线稀释技术,采用磷钼蓝分光光度法测定了环境水样中的正磷酸盐。[结果]在选定的最佳条件下,正磷酸盐浓度在1～6和6～50 mg/L范围内与吸光度(以峰高定量)呈良好的线性关系,相对标准偏差分别为1.4%和1.6%(n=11),方法的回收率在96%～105%。[结论]该测定方法可使测定线性范围较传统方法扩大1个数量级,可应用于环境监测、自动分析等过程中浓度变化较大的待测物测定。

[ Objective ] The aim was to study the feasibility of using sequential injection micro - sampling on - line dilution spectrophotometry determining phosphate in environmental samples. [ Method ] A sequence injection analysis method for the direct determination of phosphate in en- vironmental samples with on - line intelligent dilution and photometric detection was described. Phosphate was performed by the molybdenum blue method with detection at 720 run. [ Result] At the optimized condition ,the calibration graph is a linear when P043- concentration was in range of 1 - 6 and 6 - 50 mg/L. The relative standard deviation is 1.4 % for the determination of 2 mg/L PO43- （ n = 11 ） and 1.6% for the determination of 20 mg/L PO43- （ n = 11 ）. [ Conclusion ] It is characterized by high automation and wide analytical working range, which meets the requirements of automatic analysis and on - line monitoring.