An direct competitive immunofluorescence method was developed in plate to detect chlortetracycline residues in environment using the Lumichrome as fluorescent probe. Different reaction conditions such as pH , the concentration of antigen and antibody and incubation times were assayed. Under optimized conditions, chlortetracycline can be determined in the concentration range of 1×10-8--2×10-4 mol/L, and the linear equation was y=11.363x+93.026, R2=0.99. The detection limit of this method IC90 was 3.74×10-7mol/L. The recoveries of chlortetracycline at various spiking levels in the sludge samples ranged from 95.43% to 104.26%, with relative standard deviations of 3% to 6%. These data demonstrate that the excellent performance of the proposed method in the detection of chlortetracycline in water samples.

In this paper, a magnetic hollow fly ash microsphere(MHFM) was prepared by citrate sol-gel method and the Cu doped TiO2nanopowder were prepared by sol-gel process at which the novel magnetic Cu-doped TiO2photocatalyst (M-Cu/TiO2) was prepared by coating-calcining process. The crystal phase and morphology of M-Cu/TiO2were investigated by Scanning electron microscopy(SEM), X-ray diffraction(XRD), The photocatalytic activities of the prepared photocatalyst under different preparation conditions were evaluated by the degradation of methyl orange (MO). Results showed that these TiO2photocatalysts were highly efficient for the destruction of methylene orange in water. In addition, the multi-coating procedure made it possible to effectively control the physical properties of TiO2layer such as the coating thickness, amount of TiO2and photocatalytic activity. The floating catalyst made by this method could also be separated easily from the reaction system. And the multilayer film has higher photocatalytic activity than TiO2film under visible light irradiation.