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本文以铁氰化钾为探针，采用电化学方法监测铁氰化钾还原产物的量的变化，进而考察经不同时间、不同浓度的TritonX?100预处理表面的大肠杆菌（ E． coli）活性及对毒物毒性灵敏度的变化．同时，结合扫描电镜（ SEM）及生长曲线实验考察E． coli形貌及繁殖能力的变化，确定最优预处理条件．电化学分析结果表明， TritonX?100的使用量和作用时间分别为2％和1 h 时， E． coli 因呼吸作用而产生的电信号值最高；随着TritonX?100作用时间的增加，E． coli细胞活性逐渐减弱，当处理时间达到4 h，E． coli的细胞活性甚至低于未处理细胞．SEM结果表明，相对于未处理的细胞，经2％ TritonX?100处理1 h时的E． coli的细胞壁通透性增加．此外，E． coli生长曲线实验结果证明，经2％ TritonX?100处理1 h后， E． coli亲代细胞的繁殖活性有所下降，但子代的繁殖活性未受明显影响．根据条件优化的结果，经2％ TritonX?100处理1 h的E． coli被用于3，5?二氯苯酚（ DCP ）的毒性检测，作用1 h 后的半数抑制率（ IC50）为6．60 mg·L－1．而采用未经处理的 E． coli 与6．60 mg·L－1的DCP作用1 h后产生的抑制率仅为34．4％．同时，优化菌株及对照菌株分别被应用于7份实际水样的毒性检测，其抑制率范围分别为4．37％—5．90％及2．24％—3．69％．可见，经2％ TritonX?100预处理1 h的E． coli活性及对毒物毒性灵敏度均有所提高，更加适用于水质毒性检测．

In this paper, the changes of reduced productions of ferricyanide ware measured by electrochemical methods with K3Fe(CN)6 as a probe. The activities of surface?treated Escherichia coli ( E. coli) by different concentrations and different treatment times of TritonX?100, as well as the sensitivities of treated E. coli to toxicities of toxins were examined. At the same time, the changes of morphology and reproductive capacity of surface?treated E. coli were investigated by scanning electron microscopy ( SEM) and the growth curves. The results of electrochemical analysis revealed that the electrochemical signals based on activities of E. coli were maximum while concentrations and incubation times of TritonX?100 on E. coli were 2% and 1 h. But increase of exposed times, activities of E. coli were degenerated even worse than untreated E. coli when the incubation time was 4 h. Comparing with untreated cells, more permeability of E. coli cells was harvested when the cells were treated by 2% TritonX?100 at 1 h incubation time. In addition, the growth curve of E. coli results proved the breeding activities of parental cells treated by 2% TritonX?100 at 1 h incubation time decreased. But the breeding activities of offspring cells were not affected. According to the results of the optimized conditions, the cells treated by 2% TritonX?100 at 1 h incubation time were chosen to determine the toxicities of 3,5?dichlorophenol ( DCP ) . The 50% inhibiting concentration ( IC50 ) of DCP on treated cells was 6. 60 mg·L-1 , while 6. 60 mg·L-1 DCP solution on untreated cells just showed 34. 4% inhibition. Thence, optimizing strain and control strain were applied to measure the toxicities of seven water samples. The ranges of inhibition rate were 4.37%—5.90% for surface?treated cells and 2. 24%—3. 69% for untreated cells , respectively. Both the activities of treated cells and the sensitivities of treated cells to toxins were improved; therefore, these treated cells were more suitable to be employed in measurements of toxicities for water.