Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, University of South Bohemia in Ceske Budejovice, Zatisi 728/II, 389 25, Vodnany, Czech Republic.
Faculty of Natural Sciences, Department of Analytical Chemistry, Comenius University in Bratislava, Ilkovicova 6, 842 15, Bratislava, Slovak Republic.
Anal Bioanal Chem. 2020 Jul;412(18):4353-4361. doi: 10.1007/s00216-020-02672-y. Epub 2020 May 6.
Recent state-of-the-art methods developed for the analysis of polar xenobiotics from different types of biological matrices usually employ liquid chromatography with mass spectrometry. However, there are limitations when a small amount of sample mass is available. For example, individual benthic invertebrates or fish tissue samples often weigh less than 100 mg (e.g., brain, liver) but are necessary to understand environmental fate and bioaccumulation dynamics. We developed ultra-fast methods based on a direct sample introduction technique. This included coupling laser diode thermal desorption with atmospheric pressure chemical ionization mass spectrometry (LDTD-APCI-MS). We then quantitated a common selective serotonin reuptake inhibitor (citalopram) in brain tissues of individual juvenile fish after in vivo exposure to environmentally relevant concentration. Two mass spectrometric methods based on low (LDTD-APCI-triple quadrupole (QqQ)-MS/MS) and high (LDTD-APCI-high-resolution product scan (HRPS)) resolutions were developed and evaluated. Individual instrument conditions were optimized to achieve an accurate and robust analytical method with minimum sample preparation requirements. We achieved very good recovery (97-108%) across the range of 1-100 ng g for LDTD-APCI-HRPS. LDTD-APCI-QqQ-MS/MS showed poorer performance due to interferences from the matrix at the lowest concentration level. LDTD-APCI ionization was successfully validated for analysis of non-filtered sample extracts. Evaluation of final methods was performed for a set of real fish brain samples, including comparison of LDTD-APCI-HRPS with a previously validated LC-heated electrospray ionization-HRPS method. This new LDTD-APCI-HRPS method avoids the chromatographic step and provides important benefits such as analysis of limited sample masses, lower total sample volume (typically μL), and reduction in analysis time per sample run to a few seconds. Graphical abstract.
最近开发的用于分析来自不同类型生物基质的极性异生物的最先进方法通常采用液相色谱与质谱联用。然而，当可用的样品量较少时，存在一些局限性。例如，个体底栖无脊椎动物或鱼类组织样本的重量通常小于 100mg（例如脑、肝），但对于了解环境命运和生物累积动态是必要的。我们开发了基于直接样品导入技术的超快速方法。这包括将激光二极管热解吸与大气压化学电离质谱（LDTD-APCI-MS）相结合。然后，我们在活体暴露于环境相关浓度后，定量了个体幼鱼脑组织中常见的选择性 5-羟色胺再摄取抑制剂（西酞普兰）。我们开发并评估了两种基于低（LDTD-APCI-三重四极杆（QqQ）-MS/MS）和高（LDTD-APCI-高分辨率产物扫描（HRPS）分辨率的质谱方法。优化了各个仪器条件，以实现具有最小样品制备要求的准确和稳健的分析方法。我们在 LDTD-APCI-HRPS 的 1-100ng/g 范围内实现了非常好的回收率（97-108%）。LDTD-APCI-QqQ-MS/MS 由于在最低浓度水平下的基质干扰而表现出较差的性能。LDTD-APCI 离子化成功验证了对未过滤样品提取物的分析。对一组真实的鱼脑样本进行了最终方法的评估，包括 LDTD-APCI-HRPS 与先前验证的 LC 加热电喷雾电离-HRPS 方法的比较。这种新的 LDTD-APCI-HRPS 方法避免了色谱步骤，并提供了重要的优势，例如分析有限的样品量、更低的总样品体积（通常为 μL）以及每个样品运行的分析时间减少到几秒钟。
