微波消解-流动注射分光光度法测定总氮和总磷

Determination of Total Nitrogen and Total Phosphorus by Microwave Digestion and Flow Injection Spectrophotometry

以碱性过硫酸钾溶液为消解液,采用微波消解-流动注射分光光度法测定水中总氮和总磷。在碱性过硫酸钾溶液中氢氧化钠质量浓度为9.6g/L、微波功率为320W、消解管长度为16m的条件下,总氮和总磷的检出限分别为0.040m g/L和0.020mg/L,线性范围分别为0.040～3.500mg/L和0.020～2.500mg/L,相对标准偏差分别为1.6%和1.0%。微波消解-流动注射分光光度法应用于河水、湖水、化工废水等实际水样中总氮和总磷的测定,加标回收率分别为95.7%～98.1%和97.2%～102.2%。

Total nitrogen and total phosphorus in water were determined by microwave digestion and flow injection spectrophotometry using basic potassium persulphate as digestion solution. When the mass concentration of sodium hydroxide in basic potassium persulphate solution is 9. 6 g/L, the microwave power is 320 W and the length of the digestion tube is 16 m, the detection limits are 0. 040 mg/L for total nitrogen and 0. 020 mg/L for total phosphorus, the linearity ranges are 0. 040 - 3. 500 mg/L for total nitrogen and 0. 020 - 2. 50 mg/L for total phosphorus, and the relative standard deviation are 1. 6% and 1. 0%, respectively. When the proposed method is applied to the determination of total nitrogen and total phosphorus in water samples from river, lake and industry, the recoveries of added standard nitrogen and phosphorus compounds are 95.7% -98.1% and 97.2% - 102.2%, respectively.