二乙酰一肟-安替比林光度法测定游泳池水中尿素的方法改进

Method improvement for determination of urea in swimming pool water by diacetyl monooxime-antipyrine spectrophotometry

目的改进游泳池水中尿素测定的二乙酰一肟-安替比林光度法。方法基于国家标准方法,引入磷酸及三氯化铁,优化试剂浓度、加热温度和时间,简化实验操作步骤。结果优化后方法的试液总体积为4 ml,不用稀释和定容步骤,最快10 min就完成反应;尿素含量0.10 mg/L~12.8 mg/L线性相关系数(r)在0.9993以上,定量限为0.079 mg/L,相对标准偏差为0.59%~2.56%,回收率为96.4%~102.9%;同测12份水样,优化后的方法与国家标准方法结果差异无统计学意义(P>0.05);游泳池水中常见物质不干扰测定;单人单次可2 h内测定50个样品,单次检测效率与流动注射法相当;水样可在7 d内检测,比国家标准方法减少30%~80%的工作量。结论该方法操作便捷、准确可靠、检测效率高,适用于日常批量水样中尿素的检测。

Objective To improve the diacetyl monoxime-antipyrine spectrophotometric method for the determination of urea in swimming pool water.Methods Based on the national standard method,phosphoric acid and ferric chloride were introduced,the reagent concentration,heating temperature and time were optimized,and the experimental operation steps were simplified.Results After optimization,the total volume of test solution was 4 ml,and the reaction could be completed in the fastest time(10 min)without dilution and constant volume steps;the linear correlation coefficient(r)of urea content in the range of 0.10 mg/L-12.8 mg/L was greater than 0.9993,the limit of quantitation(LOQ)was 0.079 mg/L,the relative standard deviation ranged from 0.59%to 2.56%,and the recovery ranged from 96.4%to 102.9%;12 water samples were measured at the same time,there was no statistical significance on the difference between the optimized method and the national standard method(P>0.05);common substances in swimming pool water did not interfere with the determination;50 samples could be determined within 2 h by a single person at a time,and the efficiency of single detection was equivalent to that of flow injection method;water samples could be detected within 7 d,which reduced the workload by 30%-80%,compared with the national standard method.Conclusion The method is convenient,accurate,reliable and efficient,which is suitable for the determination of urea in daily batch water samples.