Normandie Université, UNIROUEN, INSA, Rouen, CNRS, COBRA, 76000, Rouen, France.
Université Paris-Saclay, CEA, INRAE, Département Médicaments et Technologies pour La Santé (DMTS), MetaboHUB, F-91191, Gif sur Yvette, France.
Anal Chim Acta. 2022 Sep 15;1226:340236. doi: 10.1016/j.aca.2022.340236. Epub 2022 Aug 15.
Collision cross sections (CCS) have been described as relevant molecular descriptors in metabolomics and lipidomics analyses for ascertaining compound identity. Ion mobility spectrometry (IMS) allows to determine CCS with different techniques, such as drift tube ion mobility spectrometry (DTIMS), traveling wave ion mobility spectrometry (TWIMS) or trapped ion mobility spectrometry (TIMS). In contrast with DTIMS where CCS can be obtained directly with measured drift times and mathematical relationship, TWIMS and TIMS techniques require an additional step of calibration to obtain CCS values. However, literature reports significantly disparate CCS values depending on the calibrant used (often more than 10%), as no consensus has been reached to define a universal CCS reference standard or harmonized calibration procedure. Therefore, publicly available CCS databases cannot be regarded as readily interoperable and exchangeable. Here, we performed a comprehensive evaluation of 11 distinct CCS calibrants in a traveling wave ion mobility spectrometry-mass spectrometry (TWIMS-MS) instrument. We showed that, using lipids from plasma as model compounds, CCS determination drastically fluctuates from one calibrant to the other with up to 25% differences, which precludes direct CCS comparison. Using the large panel of calibration curves generated, we showed that any CCS value can be efficiently re-calibrated relatively to the calibration curve made with the widely used Tune Mix solution whatever the calibration procedure originally used. The re-calibrated CCS values for each calibrant constitute a database which allows to correct any deviation on lipid CCS values whatever the calibrant originally used. Resulting corrected CCS values from plasma lipids were thus efficiently matched to those previously reported in the literature (with deviations<2%). Therefore, this work shows that unique and comparable CCS values can be obtained upon re-calibration relatively to Tune Mix CCS values, while also paving the way for the establishment of a universal CCS database of various metabolite or lipid classes.
碰撞截面（CCS）已被描述为代谢组学和脂质组学分析中确定化合物身份的相关分子描述符。离子淌度谱（IMS）允许使用不同的技术来确定 CCS，例如漂移管离子淌度谱（DTIMS）、行波离子淌度谱（TWIMS）或俘获离子淌度谱（TIMS）。与 DTIMS 不同，在 DTIMS 中，可以通过测量的漂移时间和数学关系直接获得 CCS，TWIMS 和 TIMS 技术需要额外的校准步骤才能获得 CCS 值。然而，文献报告表明，由于尚未达成共识来定义通用的 CCS 参考标准或协调的校准程序，因此取决于所用的校准剂，CCS 值存在显著差异（通常超过 10%）。因此，公开的 CCS 数据库不能被视为可直接互操作和可交换的。在这里，我们在旅行波离子淌度谱-质谱（TWIMS-MS）仪器中对 11 种不同的 CCS 校准剂进行了全面评估。我们表明，使用来自血浆的脂质作为模型化合物，CCS 的测定值从一种校准剂到另一种校准剂波动很大，差异高达 25%，这排除了直接的 CCS 比较。使用生成的大校准曲线面板，我们表明，无论最初使用何种校准程序，任何 CCS 值都可以相对于使用广泛使用的 Tune Mix 溶液生成的校准曲线进行有效重新校准。对于每个校准剂的重新校准的 CCS 值构成了一个数据库，该数据库允许校正任何校准剂最初使用时的脂质 CCS 值的偏差。来自血浆脂质的校正后的 CCS 值与文献中先前报道的值（偏差<2%）有效匹配。因此，这项工作表明，通过相对于 Tune Mix CCS 值进行重新校准，可以获得唯一且可比的 CCS 值，同时也为建立各种代谢物或脂质类别的通用 CCS 数据库铺平了道路。
