Innovative ion mobility - mass spectrometry workflows for discovering veterinary drug metabolites in tissues and the creation of sensitive methods for their quantification.

确保食品安全是公共卫生的优先事项;检测禁用物质尤其令人关切，因为它们经常被非法使用，并可能导致人类严重的不良健康影响，如癌症。拥有准确和灵敏的方法对食品安全至关重要，因此，液相色谱-质谱法（LC-MS）由于其高灵敏度和选择性而成为分析生物样品的重要工具。我们正在开发的兽药残留分析工作流程包括两个主要步骤：适当药物残留的鉴定和定量。在这两个步骤中，生物基质通常产生非常复杂的质谱，这对选择性和检测限产生不利影响。 由于离子迁移率的分离机制不同于LC和MS，因此离子迁移率装置有助于缓解由生物基质引起的问题。因此，将离子迁移率与LC-MS组合导致更大的分离能力，从而简化复杂的分析。由于LC-FAIMS-MS具有非常高的灵敏度和选择性，我们的工作流程在两个步骤中都采用了高场非对称波形离子迁移谱（FAIMS）。赛默飞世尔和我的团队合作开发了一个新的FAIMS接口（FAIMS Pro），解决了FAIMS的初始挑战。然而，FAIMS Pro主要是为蛋白质组学而设计的，在蛋白质组学中容易发生完全的离子去溶剂化。对于使用高液体流速的小分子应用，需要彻底研究关键参数，最显著的是溶剂效应和气体改性剂的整合。 开发一个优化的FAIMS设备用于小分子分析是我所提出的研究的关键一步。结合使用气体改性剂在FAIMS的溶剂效应的调查，将被用来开发一种方法，允许溶剂化离子进入FAIMS，而不会产生不利影响的灵敏度或鲁棒性。这将是与Thermo Fisher共同努力的一个组成部分，重新设计FAIMS Pro设备，专门用于小分子（sFAIMS），从而通过允许更多的离子进入FAIMS来实现最大灵敏度。将sFAIMS集成到我们的食品安全工作流程中将改善这两个步骤;主要用于克服定量方法中有问题分析物的化学背景问题，但也可以在识别步骤中使用额外的分离能力，以帮助软件从复杂的基质中提取合适的药物残留物进行定量。 除了使用食品和组织中兽药残留的工作流程外，其适应性还使其适用于其他食品安全应用，如食品真实性。从长远来看，该工作流程可以很容易地适用于需要高选择性和灵敏度的其他领域，例如在健康和医学中识别和量化疾病生物标志物。

Ensuring food is safe is a public health priority; detection of banned substances are of particular concern as they are often illegally used and can lead to serious adverse health effects in humans, such as cancer. Having accurate and sensitive methods is vital in food safety and consequently, liquid chromatography - mass spectrometry (LC-MS) has become an essential tool due to its high sensitivity and selectivity for analyzing biological samples. The workflow we are developing for analyzing veterinary drug residues involves two main steps; identification and quantification of a suitable drug residue. Within both these steps, biological matrices typically produce very complex mass spectra, which adversely affects selectivity and detection limits. Ion mobility devices help alleviate issues caused by the biological matrix since the separation mechanism of ion mobility differs from both LC and MS. Thus, combining ion mobility with LC-MS leads to a greater separation capacity that simplifies complex analyses. Our workflow employs high-field asymmetric waveform ion mobility spectrometry (FAIMS) in both steps since LC-FAIMS-MS offers very high sensitivity and selectivity. A collaborative effort between Thermo Fisher and my group led to the development of a new FAIMS interface (FAIMS Pro) that addressed initial challenges with FAIMS. However, FAIMS Pro was designed primarily for proteomics where complete ion desolvation readily occurs. For small molecule applications that use high liquid flow rates, a thorough investigation of critical parameters, most notably solvent effects and the integration of gas modifiers, is needed. Developing an optimized FAIMS device for small molecule analysis is a critical step in my proposed research. An investigation of solvent effects combined with the use of gas modifiers in FAIMS, will be used to develop an approach to allow solvated ions to enter FAIMS without adversely affecting sensitivity or robustness. This will be an integral part of a joint effort with Thermo Fisher to redesign the FAIMS Pro device for use specifically with small molecules (sFAIMS) thereby enabling maximal sensitivity by allowing significantly more ions into FAIMS. Integration of sFAIMS into our food safety workflows will improve upon both steps; primarily for overcoming chemical background issues for problematic analytes in quantitative methods, but also in the identification step in using the extra separation capacity to assist the software in extracting suitable drug residues for quantification from complex matrices. In addition to using the workflow for veterinary drug residues in food and tissue, the adaptability makes it amenable to other food safety applications such as food authenticity. Longer term, the workflow can be readily adapted for use in other fields in which high selectivity and sensitivity are required, for example, in identifying and quantifying disease biomarkers in health and medicine.