National Institute of Nutrition and Seafood Research (NIFES), P.O. Box 2029 Nordnes, N-5817 Bergen, Norway.
Anal Chem. 2016 Nov 15;88(22):11169-11177. doi: 10.1021/acs.analchem.6b03381. Epub 2016 Nov 4.
Ion mobility spectrometry allows for the measurement of the collision cross section (CCS), which provides information about the shape of an ionic molecule in the gas phase. Although the hyphenation of traveling-wave ion mobility spectrometry (TWIMS) with high-resolution quadrupole time-of-flight mass spectrometry (QTOFMS) has been mainly used for structural elucidation purposes, its potential for fast screening of small molecules in complex samples has not yet been thoroughly evaluated. The current work explores the capabilities of ultrahigh-performance liquid chromatography (UHPLC) coupled to a new design TWIMS-QTOFMS for the screening and identification of a large set of pesticides in complex salmon feed matrices. A database containing TWIMS-derived CCS values for more than 200 pesticides is hereby presented. CCS measurements showed high intra- and interday repeatability (RSD < 1%), and they were not affected by the complexity of the investigated matrices (ΔCCS ≤ 1.8%). The use of TWIMS in combination with QTOFMS was demonstrated to provide an extra-dimension, which resulted in increased peak capacity and selectivity in real samples. Thus, many false-positive detections could be straightforwardly discarded just by applying a maximum ΔCCS tolerance of ±2%. CCS was proposed as a valuable additional identification point in the pesticides screening workflow. Several commercial fish feed samples were finally analyzed to demonstrate the applicability of the proposed approach. Ethoxyquin and pirimiphos-methyl were identified in most of the analyzed samples, whereas tebuconazole and piperonil butoxide were identified for the first time in fish feed samples.
离子淌度谱可用于测量碰撞截面（CCS），提供有关气相中离子分子形状的信息。尽管飞行时间离子淌度谱（TWIMS）与高分辨率四极杆飞行时间质谱（QTOFMS）的串联主要用于结构解析目的，但它在复杂样品中小分子的快速筛选方面的潜力尚未得到彻底评估。本工作探索了超高效液相色谱（UHPLC）与新型 TWIMS-QTOFMS 联用在复杂三文鱼饲料基质中对大量农药进行筛选和鉴定的能力。本研究提出了一个包含 200 多种农药的 TWIMS 衍生 CCS 值数据库。CCS 测量具有高日内和日间重复性（RSD < 1%），并且不受所研究基质复杂性的影响（ΔCCS ≤ 1.8%）。证明了 TWIMS 与 QTOFMS 的联用提供了一个额外的维度，从而在实际样品中增加了峰容量和选择性。因此，通过应用最大 ±2%的ΔCCS 容限，可以直接排除许多假阳性检测。CCS 被提议作为农药筛选工作流程中一个有价值的附加鉴定点。最后对几个商业三文鱼饲料样品进行了分析，以证明所提出方法的适用性。在所分析的大多数样品中均检测到乙氧喹啉和丙溴磷，而在三文鱼饲料样品中首次检测到戊唑醇和哌虫啶。
