超高效液相色谱-四极杆飞行时间质谱法非靶向筛查西红柿中三唑类杀菌剂

建立了超高效液相色谱-四极杆飞行时间质谱非靶向快速筛查西红柿中三唑类杀菌剂的方法。样品用乙腈提取、QuEChERS净化、BEH C 18(100 mm×2.1 mm,1.7μm)色谱柱分离,以乙腈和水(均含0.1%(v/v)甲酸)为流动相进行梯度洗脱,采用四极杆飞行时间质谱仪进行检测。质谱离子源为电喷雾电离源,采集方式为正离子数据非依赖分析MS E扫描模式。将19种三唑类杀菌剂按化学结构的不同分为8类。首先通过对8类典型三唑类杀菌剂中代表性的8种标准品的二级质谱图进行分析,总结出三唑类杀菌剂经碰撞诱导解离后产生的特征碎片离子和特征中性碎片丢失的质谱裂解规律,然后再利用另外11种三唑类杀菌剂标准品进行验证,并用于16份北京市售西红柿的非靶向筛查,在1份样品中筛查出烯唑醇。该方法快速、简便、准确率高,可为食品中三唑类杀菌剂残留的筛查提供参考。

Non-targeted screening of triazole fungicides in tomatoes by ultra-high performance liquid chromatography-quadrupole-time of flight mass spectrometry

In order to cope with the differences in international trade regulations, it is necessary to establish a rapid non-targeted screening method for triazole fungicides in food. Therefore, a non-targeted method based on ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was established for the rapid screening of triazole fungicides in tomatoes. Tomato samples were extracted with acetonitrile and then purified by QuEChERS. The purified solution was separated on a BEH C₁₈ column (100 mm×2.1 mm, 1.7 μm) using a gradient mobile phase consisting of acetonitrile and water (both containing 0.1% formic acid). Full information tandem mass spectrometry (MS^E) acquisition using electrospray ion source under positive ion mode was performed. The 19 triazole fungicides were divided into eight groups based on their structural differences. The secondary mass fragments of eight typical standards in the eight groups of triazole fungicides were analyzed, and then, the regularities of the characteristic fragment ions and neutral loss fragments produced by collision-induced dissociation of the triazole fungicides were summarized. The fragmentation regularity was further verified by the other 11 triazole fungicides. A total of 16 tomato samples collected from local supermarkets in Beijing were screened using this non-targeted method. Diniconazole was identified and confirmed in one sample, which demonstrated that the method could achieve rapid and accurate non-targeted screening of triazole fungicides in tomatoes. The proposed method is highly efficient, sensitive, and accurate, thus providing a reference for screening triazole fungicide residues in food.