Institute of Chemistry at São Carlos (IQSC), University of São Paulo, São Carlos, SP 13560-970, Brazil.
Institute of Chemistry at São Carlos (IQSC), University of São Paulo, São Carlos, SP 13560-970, Brazil.
J Chromatogr A. 2022 Jul 5;1674:463143. doi: 10.1016/j.chroma.2022.463143. Epub 2022 May 13.
A 25 µm i.d x 1.2 m length PS-DVB porous layer open tubular column (PLOT) was prepared and assessed in the configuration of a nano liquid chromatography coupled to an electron ionization mass spectrometry system (OT-nanoLC-EI-Ms), via the direct insertion of the column outlet into the ionization source. The developed system's operational parameters were comprehensively studied, and the setup performance was investigated employing both unidimensional and column switching configurations. As a result, the OT-nanoLC-EI-MS system demonstrated competitive applicability in separating non-amenable ESI compounds, such as polyaromatic hydrocarbons (PAHs) and non-amenable GC compounds such as thermolabile pesticides. Furthermore, with excellent chromatographic performance, the PLOT columns can work under more compatible EI-detection conditions - such as the elution with 100% organic solvent. For example, PAHs retention factors ranged between 1.5 and 2.2 for 100% MeCN mobile phase, and more than 33,000 plates per meter for naphthalene at 50 nL/min flow rate. In analyzing thermolabile pesticides, the column switching PLOT-nanoLC-EI-MS system provided LODs of 25 µg/L, demonstrating suitable intra e interday reproducibility (% RSD < 13%, n = 3), and possibilities the direct injection of raw samples with suitable robustness.
一根 25µm i.d x 1.2m 长的 PS-DVB 多孔层开管柱（PLOT）被制备并在纳米液相色谱与电子电离质谱联用系统（OT-nanoLC-EI-MS）中进行了评估，通过将柱出口直接插入离子源来实现。对开发系统的操作参数进行了全面研究，并通过一维和柱切换两种配置来研究该装置的性能。结果表明，OT-nanoLC-EI-MS 系统在分离不适合电喷雾电离（ESI）的化合物方面具有竞争力，如多环芳烃（PAHs）和不适合气相色谱（GC）的化合物，如热不稳定的农药。此外，PLOT 柱具有出色的色谱性能，可以在更兼容的 EI 检测条件下工作 - 例如，用 100%有机溶剂洗脱。例如，在 100% MeCN 流动相中，PAHs 的保留因子在 1.5 到 2.2 之间，在 50nL/min 的流速下，萘的理论塔板数超过 33000 块/米。在分析热不稳定的农药时，柱切换 PLOT-nanoLC-EI-MS 系统提供了 25µg/L 的检出限，表现出适合日内和日间的重现性（%RSD<13%，n=3），并且具有直接注入原始样品的可能性，具有适当的稳健性。
