A wide use of quantum dots-based fluoroimmunoassay strongly requires to futher increase luminescent intensity of the quantum dots and stability of the antibody. To obtain CdTe/CdS core/shell type quantum dots, CdTe quantum dots was synthesized in aqueous medium and then wrapped with CdS shell well, in which thioglycolic acid or glutathione was used as a stabilizer. Then, the CdTe/CdS was covalently conjugated on the surface of antibody using EDC/NHS as crossing-linking reagent and the antibody was then blocked by bovine serum albumin. The experiments show that glutathione as stabilizer is better than thioglycolic acid. Compared with CdTe quantum dots, the luminescent intensity and stability of glutathione-stabilized CdTe/CdS core/shell quantum dots are higher 6 times and 2 times, respectively. The reason is that relatively long carbon chain of glutathione remarkably reduces effect of the CdTe/CdS quantum dots on the spatial confugation of antibody, especially for active sites regions. This results in enhancing stability of the antibody. In order to evaluate the stability of the antibody, the luminescent intensity change value of CdTe/CdS quantum dots-antibody complex deposited different time at 4 ℃ were measured before and after imcubated with deoxynivalenol. The results showed that the antibody can remain good stability at least 7 d. Based on the high performance of glutathione stabilized CdTe/CdS quantum dots, we developed a novel method for determination of deoxynivalenol by fluoroimmunoassay in the work. When concentration of deoxynivalenol is in the range from 0 to 0.9 ng•mL^－1, its relative luminescent intensity has a good linear range relationship against the concentration of deoxynivalenol with a 0.9992 of the correlation coefficients (R²), and the detection limit was found to be 0.038 ng•mL^－1, that is obviously better than other methods in literatures such as GC-ECD, HPLCand HPLC-MS. Proposed method has been successfully applied to deoxynivalenol analysis in real wheat.

Key words: CdTe/CdS quantum dots, deoxynivalenol, fluoroimmunoassay, glutathione, wheat flour