ONIRIS, USC 2013 LABERCA, Atlanpole - La Chantrerie, BP 50707, Nantes F-44307, France.
Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2011 Sep;28(9):1261-73. doi: 10.1080/19440049.2011.583283. Epub 2011 Jun 27.
Perfluorinated compounds (PFCs) are usually monitored by high-performance liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) on triple quadrupole instruments. Although not yet widely implemented in the field, high-resolution mass spectrometry (HRMS) today appears as a valuable alternative for these halogenated chemicals due to their significant mass defect. Indeed, this second approach offers a way to cope with particular matrix effects caused by co-eluting and isobaric interferences affecting the measurement of some PFCs in fish. The present study compares three different LC-MS-related instruments and various signal acquisition modes, from low-resolution full-scan and selected ion-monitoring (SIM) mode on a triple quadrupole (QqQ) instrument to high-resolution full-scan or product ion-scan mode on orbital trap (LTQ-Orbitrap) or quadrupole-time-of-flight (Q-TOF) devices. Performances are compared for seven model compounds belonging to seven PFCs subclasses: perfluoralkylsulfonate, perfluoroalkylcarboxylate, perfluoroalkylsulfinate, perfluoroalkyl-sulfonamide, fluorotelomer saturated acid, fluorotelomer unsaturated acid and perfluoroalkylphosphonic acid. Low-resolution MS/MS was found to be unsurprisingly reliable for extended multi-residue monitoring. However, the high stability of PFCs leads to a relatively poor and non-specific fragmentation pathway in MS/MS. In addition, biliary acid-interfering compounds (e.g. taurochenodeoxycholic acid), which where encountered in the present case in fish samples but that may be present in other biological samples, were found particularly disturbing in low-resolution MS/MS. Indeed, these interferences presented the same retention time and diagnostic signals as PFOS, leading to a possible overestimation of the PFOS quantification in LC-MS/MS. On the other hand, high-resolution MS and MS/MS (LTQ-Orbitrap and Q-TOF) provided better results in terms of signal specificity and sensitivity. For instance, the estimated limits of detection (LOD) reached for PFOS on QqQ, Q-TOF and LTQ-Orbitrap instruments were 3.8, 0.7 and 0.5 pg injected, respectively.
全氟化合物 (PFCs) 通常通过高效液相色谱与串联质谱联用 (LC-MS/MS) 在三重四极杆仪器上进行监测。尽管高分辨率质谱 (HRMS) 尚未在该领域广泛应用，但由于其显著的质量缺陷，它似乎是这些卤化化学品的一种有价值的替代方法。事实上，这种方法为应对因共洗脱和同量异位干扰而影响某些 PFC 在鱼类中测量的特殊基质效应提供了一种方法。本研究比较了三种不同的与 LC-MS 相关的仪器和各种信号采集模式，从三重四极杆 (QqQ) 仪器上的低分辨率全扫描和选择离子监测 (SIM) 模式到轨道阱 (LTQ-Orbitrap) 或四极杆飞行时间 (Q-TOF) 仪器上的高分辨率全扫描或产物离子扫描模式。对属于七种 PFC 亚类的七种模型化合物进行了性能比较：全氟烷基磺酸盐、全氟烷基羧酸、全氟烷基磺酸盐、全氟烷基磺酰胺、氟代饱和烷烃酸、氟代不饱和烷烃酸和全氟烷基膦酸。低分辨率 MS/MS 用于扩展多残留监测时被证明是可靠的。然而，PFCs 的高稳定性导致 MS/MS 中相对较差和非特异性的碎片化途径。此外，在本案例中在鱼类样本中遇到的胆汁酸干扰化合物（例如牛磺鹅脱氧胆酸），可能存在于其他生物样本中，在低分辨率 MS/MS 中特别令人困扰。事实上，这些干扰物与 PFOS 具有相同的保留时间和诊断信号，可能导致 LC-MS/MS 中 PFOS 定量的高估。另一方面，高分辨率 MS 和 MS/MS（LTQ-Orbitrap 和 Q-TOF）在信号特异性和灵敏度方面提供了更好的结果。例如，在 QqQ、Q-TOF 和 LTQ-Orbitrap 仪器上对 PFOS 的估计检测限 (LOD) 分别为 3.8、0.7 和 0.5 pg 注入。
