Molecular Analytical Sciences Centre for Doctoral Training, University of Warwick, Coventry CV4 7AL, England.
Department of Chemistry, University of Warwick, Coventry CV4 7AL, England.
Anal Chem. 2022 Mar 29;94(12):4954-4960. doi: 10.1021/acs.analchem.1c03463. Epub 2022 Mar 14.
Sample preparation and instrument parameters have regularly been demonstrated to impact upon the observed results in atmospheric pressure photoionization, mass spectrometry (MS), and analytical techniques in general but may be overlooked when such methods are applied to the characterization of real-world samples. An initial investigation into different solvent systems demonstrated that the inclusion of ethyl acetate inverted the ratio of relative intensities of radical and protonated species (R/P). Design of experiments was performed and indicated that the injection flow rate is also a significant factor. The impact of the solvent system and flow rate on signal intensity, the observed compositional profile, and R/P of selected molecular groups is demonstrated further. An inversion of R/P is observed at higher flow rates in solvent systems commonly used in petroleomics studies, effecting a loss of molecular speciation. The findings presented reiterate the critical importance in considering experimental parameters when interpreting the results of analytical procedures.
样品制备和仪器参数通常被证明会影响大气压光电离、质谱（MS）和一般分析技术中的观察结果，但在将这些方法应用于实际样品的表征时，可能会被忽视。初步研究不同的溶剂系统表明，加入乙酸乙酯会改变自由基和质子化物质（R/P）的相对强度比。实验设计表明，注入流速也是一个重要因素。进一步展示了溶剂系统和流速对信号强度、所选分子基团的观察组成分布和 R/P 的影响。在石油组学研究中常用的溶剂系统中，随着流速的增加，观察到 R/P 发生反转，导致分子形态发生损失。所提出的研究结果重申了在解释分析程序结果时考虑实验参数的重要性。
