The bacterial retention performances of mixed cellulose membrane,polycarbonate membrane,cellulose nitrate membranes and cellulose acetate membranes with 13 mm-diameter were investigated under the same conditions.The total plate count of bacteria in the tested sample was 10 CFU/mL.The filtrate volume was 50 mL,and the filtration was repeated 5 times.When the aperture was 0.22 μm,the average retention rates of four membranes were 100％,94％,84％ and 72％,respectively.When the aperture was 0.45 μm,they were 92％,82％,70％ and 70％,respectively.Therefore,the best membrane to retain bacteria was mixed cellulose membrane with 0.22 μm aperture.50 mL samples respectively containing bacteria 42 CFU/mL,20 CFU/mL,10 CFU/mL and 4 CFU/mL were separately filtered through mixed cellulose membrane.The bacteria on the membranes were determined by ATP bioluminescent method.There was a good linear correlation between fluorescent value and the bacteria concentration(R2 ＞ 0.9).The experiment results proved that mixed cellulose membrane with 0.22 μm aperture could meet the requirements about concentration and measurement of low-level bacteria content sample by ATP bioluminescent method.%在相同的操作条件下考察了直径13 mm的混合纤维素酯膜、聚碳酸酯膜、醋酸纤维素膜、硝酸纤维素膜等4种常用微孔滤膜对细菌的截留能力.以细菌总数含量为10 CFU/mL的水样为待测样品,过滤体积为50mL,过滤测定5次.当孔径为0.22 μm时,4种滤膜的平均截留率依次为100％ 、94％ 、84％和72％;当孔径为0.45μm时,4种滤膜的平均截留率依次为92％、82％、70％和70％.因此,孔径为0.22μm的混合纤维素酯膜对细菌的截留效果最好.以该滤膜过滤细菌总数含量为42CFU/mL、20 CFU/mL、10 CFU/mL、4 CFU/mL的水样各50 mL,然后以ATP生物发光法测定膜上细菌,所得ATP荧光值与细菌浓度的线性相关系数R2 ＞0.9,线性相关性较好.结果显示,0.22 μm的混合纤维素酯膜能够满足ATP生物发光法对微菌含量样品的富集测定要求.
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