Bacteria are found all over nature and the environment.They are widely existed in soil,nature waters,intestinal tract and skin of human and animals.Most of bacteria do their duty in ecological system,and many are closely related to plants or animals in beneficial relations.However,some of infectious diseases can be caused by the inbreak of bacteria into the viscera.Therefore,the development of detection and identification methods for bacteria is necessary in public health,water and food safety.The conventional plate-counting method is an effective way to get an accuracy result for bacteria detection.However,the method is extremely time-consuming since it usually takes several days on average to get a result.Based on this condition,a large number of other methods have been developed,such as immuno-based methods,PCR-based methods,biosensor-based methods,and so on.Although immuno-based,biosensor-based,and normal PCR-based methods can effectively reduce the detection time for bacteria,the detection limits for bacteria are usually in the range of 103 to 104 cfu mL-1,or just qualitative results are provided.Real-time PCR-based method can effectively improve the detection sensitivity of bacteria with a detection limit lower than 102 cfu g-1.However,culture enrichment was still a necessary step for high sensitivity,which is time-consuming and limits the rapid detection of low concentration of bacteria.Herein,we report a method for rapid and sensitive detection and quantification of L.monocytogenes and E.coli.Silica coated magnetic particles functionalized with Nmethylimidazolium ion(MIm-MPs)were prepared and characterized by Fourier transform infrared spectroscopy,transmission electron microscopy,zeta potential,and vibrating sample magnetometry.They were found to enable effective capture of bacteria as confirmed by TEM imaging of the conjugates.The factors including pH of binding buffer,concentration of elution buffer and elution time which may affect the capture and elution efficiencies are optimized.The adsorption capacities of the MIm-MPs for L.monocytogenes and E.coli are 6.2 × 108 and 1.3 × 108 cfu mg-1,respectively.And their efficiency for capturing L.monocytogenes and E.coli from tap water and mineral water is >98% when applying less than 80 mg of Mim-MPs and an adsorption time of 10 min.The Mim-MPs were used to capture bacteria from large volumes of aqueous solutions.A combination of polymerase chain reaction(PCR)with capillary electrophoresis(CE)allows for a quantification of low levels of L.monocytogenes(102 cfu mL-1)and E.coli(101 cfu mL-1).The whole process takes <6 h which is much less than in case of the traditional plate-counting method which can take several days.Good agreements were obtained between the data obtained by the Mim-MPs-PCR-CE-based method and the plate-counting method.