滤膜法测定悬浮物出现负误差原因研究

Research on Reasons for Occurrence of Error When Measuring Suspended Solids by Filter Membrane

为了对滤膜法测定水中悬浮物出现负误差的情况进行研究，从滤膜的前处理到滤膜的选择进行了一系列实验，发现主要原因是滤膜在实验的过程中产生失重。对几种微孔滤膜进行了空白实验，得出有机滤膜的空白校正值为0.0000～0.0004g，低于或等于悬浮物的称量误差，此类滤膜用于水中悬浮物的测定，能减少恒重次数，缩短实验时间，提高测定结果的科学性和准确性。

A series of tests were conducted from the pretreatment to the selection of filter membrane in order to find out the reasons causing the errors when filter membrane was used to measure suspended solids.The weight loss of filter membrane was discovered to be the major factor.Blank experiments of several filter membranes were done to compare the blank correction value of different types of filter membranes.The results showed that the value of one organic filter membrane is 0.0000g to 0.0004g,which is no more than the weighting error of suspended solids. This organic filter membrane can reduce the occurrence of constant weight and shorten the test duration and improve the accuracy of this process.