国家监测网方法测定地表水中总磷与国标法差异及改进

比较了国家地表水环境质量监测网总磷测定方法与国标法的差异。浊度补偿与过滤两种去除浊度方法测定结果的绝对偏差为-0.02~0.07 mg/L,其中含细颗粒物较多的样品绝对偏差较大,为0.04~0.07 mg/L,因此采用过滤法时,需对含较多细颗粒物的水样进行浊度补偿。对国家地表水环境质量监测网方法进行了改进,将原来的过滤后定容改为定容摇匀后过滤。方法改进前后,样品测定值的相对偏差不大于3.4%,绝对偏差为-0.01~0.02 mg/L。改进后的方法与原方法测定结果没有显著差异,但改进后方法浊度贡献减少,试剂用量减半,而且可操作性强,更加简便和环境友好。

Differences between monitoring network method and national standard method for determining total phosphorus and modification

The differences between national surface water quality monitoring network method and national standard method in terms of total phosphorus determination were studied.It was investigated about the differences of turbidity compensation and filtration method,and the results showed that the absolute deviation of the two methods was-0.02-0.07 mg/L and the absolute deviation was 0.04-0.07 mg/L when the fine particulate content in the samples was high.More turbidity compensation should be done for the samples with high content of fine particulate when using filtration method.The method of national surface water quality monitoring network was modified by changing the order of constant volume and filtration.For the same sample,the determination result of the modified method was not significantly different from that of the original method,and the relative deviation of the two methods was not more than 3.4%,and the absolute deviation was-0.01-0.02 mg/L,respectively.The detection results by modified method had no significant difference with that by the original method.With lower contribution of turbidity and half amounts of reagents,the modified method was operational,more simple and environmental friend,compared with the original method.