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目的建立一种快速准确测定游泳池水中尿素的流动注射分光光度法。方法尿素在强酸环境下与二乙酰一肟及硫代氨基脲加热可生成红色的二嗪衍生物,采用QC8500流动注射分析仪,通过在线加热及在线冷凝,于530 nm处进行比色测定。结果在0.040 mg/L~10.000 mg/L时,尿素的吸收峰面积(y)与其浓度(x)成线性关系,标准曲线回归方程为y=4.83x+1.06,相关系数r=0.999 9,检出限为0.005 6 mg/L,相对标准偏差(RSD)<4.5%。对普通淡水浴池水样和海水浴场水样进行加标回收实验,回收率为98.0%~103.3%。本方法的测定结果与国家标准方法的检测结果差异无统计学意义。样品分析速度为30样/h。结论本方法线性范围宽,简便快速,适合游泳池水中尿素的批量测定。
Objective To establish a rapid and accurate method for the determination of urea in swimming pool water by flow injection spectrophotometry. Methods Urea was diazotized with diacetyloxime and thiosemicarbazide in the presence of strong acid to produce red diazine derivatives. Colorimetric determination was performed at 530 nm by online heating and on-line condensation using a QC8500 flow injection analyzer. Results When the concentration of 0.040 mg / L ~ 10.000 mg / L, the peak area of urea (y) was linear with its concentration (x). The standard curve regression equation was y = 4.83x + 1.06 with correlation coefficient r = 0.999 9. The output was limited to 0.005 6 mg / L and the relative standard deviation (RSD) was <4.5%. The standard freshwater bath water samples and beach water samples were spiked recovery experiments, the recovery rate was 98.0% ~ 103.3%. The results of this method and the national standard test results showed no significant difference. Sample analysis speed of 30 samples / h. Conclusion The method has a wide linear range, is simple and fast, and is suitable for the batch determination of urea in swimming pool water.