Dual flow immunochromatographic assay for rapid and simultaneous quantitative detection of ochratoxin A and zearalenone in corn, wheat, and feed samples

A one-step dual flow immunochromatographic assay (DICGA), based on a competitive format, was developed for simultaneous quantification of ochratoxin A (OTA) and zearalenone (ZEN) in corn, wheat, and feed samples. The limit of detection for OTA was 0.32 ng/ml with a detection range of 0.53‒12.16 ng/ml, while for ZEN it was 0.58 ng/ml with a detection range of 1.06‒39.72 ng/ml. The recovery rates in corn, wheat, and feed samples ranged from 77.3% to 106.3% with the coefficient of variation lower than 15%. Naturally contaminated corn, wheat, and feed samples were analyzed using both DICGA and liquid chromatography-tandem mass spectrometry (LC-MS/MS) and the correlation between the two methods was evaluated using a regression analysis. The DICGA method shows great potential for simple, rapid, sensitive, and cost-effective quantitative detection of OTA and ZEN in food safety control.中文概要目的优化建立二联胶体金免疫层析试纸条, 实现对玉米、面粉和饲料中赭曲霉毒素A和玉米赤霉烯酮的同时快速定量检测。创新点采用纳米金颗粒标记真菌毒素单克隆抗体, 基于竞争反应模式, 通过对金颗粒尺寸、免疫层析相关组成材料及缓冲液配方的系列优化, 同时借助手持式信号读取装备, 实现对谷物和饲料中赭曲霉毒素A和玉米赤霉烯酮的同时定量检测。该方法简单、快速且成本低, 与液相色谱串联质谱(LC-MS/MS)一致性良好, 便于基层单位的推广使用。方法采用柠檬酸钠还原法制备纳米金颗粒并标记获得金标抗体。通过在基于竞争反应的免疫层析检测体系中, 同时设置两条检测线(T1、T2)以实现两种毒素的同时检测, 最终采用金标信号读数仪实现定量检测。结论制备的二联定量胶体金试纸条对赭曲霉毒素A和玉米赤霉烯酮的检测限分别为0.32和0.58 ng/ml (图5), 在玉米、小麦和饲料样本中的加标回收率为77.3%~106.3%, 且变异系数均小于15% (表2)。制备的二联定量胶体金免疫层析试纸条和LC-MS/MS对玉米、小麦和饲料等天然样本中赭曲霉毒素A和玉米赤霉烯酮的定量检测结果相关性较好(表3和图7), 具有较好的应用价值。