磁控双色上转换荧光适配体传感器同时检测玉米和燕麦粉中的赭曲霉毒素A与玉米赤霉烯酮

目的 建立磁控双色上转换荧光法同时检测玉米和燕麦粉中赭曲霉毒素A(ochratoxin A,OTA)与玉米赤霉烯酮(zearalenone,ZEN)的含量。方法 利用溶剂热法合成了两种油酸封端的核壳型上转换纳米材料,通过表面改性法和戊二醛法制备了表面分别偶联OTA、ZEN适配体的核壳型上转换荧光探针。同时制备了表面原位生长四氧化三铁纳米颗粒的二硫化钼纳米片,作为淬灭剂。OTA、ZEN和适配体特异性结合后,通过磁分离后检测溶液的荧光强度值,从而实现OTA和ZEN的检测。结果 在最佳检测条件下,OTA与ZEN的质量浓度在0.05～500.00 ng/mL范围内与两种上转换荧光探针的荧光强度的对数值呈良好的线性关系,相关系数分别为0.9949和0.9972,对OTA的检出限为3.97×10^-2ng/mL,对ZEN的检出限为3.11×10^-2ng/mL,应用于玉米粉和燕麦粉中OTA和ZEN的检测,加标回收率为91.7%～109.4%。结论 该方法检测灵敏度较高,并具有较好的特异性,可用于玉米和燕麦粉中OTA和ZEN的高灵敏检测。

Simultaneous determination of ochratoxin A and zearalenone in maize and oat flour by magnetically controlled Bi-color upconversion fluorescent aptasensor

ABSTRACT: Objective To develop an upconversion fluorescence method for the simultaneous determination of ochratoxin A (OTA) and zearalenone (ZEN) in food. Methods Two core-shell upconversion nanoparticles capped with oleic acid were synthesized by a solvothermal method, and core-shell upconversion fluorescent probes coupled with OTA and ZEN aptamers were prepared by surface modification and glutaraldehyde methods, respectively. Molybdenum disulfide nanosheets with in situ growth of iron tetroxide nanoparticles on the surface were also prepared as quenching agents. When OTA and ZEN bound specifically to aptamers respectively, the fluorescence intensity values of the solutions were detected by magnetic separation, thus enabling the detection of OTA and ZEN concentrations. Results The method showed a good linear relationship between the concentrations of OTA and ZEN in the range of 0.05-500.00 ng/mL and the logarithmic values of fluorescence intensity of the two upconverted fluorescent probes under the optimal detection conditions, with correlation coefficients of 0.9949 and 0.9972, respectively, and the limits of detection of 3.97×10-2 ng/mL for OTA and 3.11×10-2 ng/mL for ZEN were obtained, which were applied to the determination of OTA and ZEN in corn flour and oat flour with the spiked recoveries of 91.7%-109.4%. Conclusion The method is sensitive and has good specificity for the highly sensitive detection of OTA and ZEN in food