Oxygenated polycyclic aromatic hydrocarbons (OPAHs) are mutagenic and ubiquitous pollutants to both humans and environment. Routine analytical methods for differentiating their isomers still remain challenges. In this article, we present laser desorption laser post-ionization time-of-flight mass spectrometry (LDPI-TOFMS) as a new approach for the characterization of isomers of OPAHs. Herein, a pulse laser with the wavelength of 532 nm is used to desorb analytes which are post-ionized by another pulse laser with wavelength of 266 nm. A clear discrimination of quasi-molecular ion peaks and characteristic peaks among OPAHs could be observed. We have demonstrated that LDPI-TOFMS can be used to distinguish isomers quickly and clearly irrespective of the polarity and solubility of samples. Additionally, results from other four mass spectrometry (MS) based methods have also been compared, despite the fact that they were unable to distinguish the isomers or unable to obtain molecular ion peaks. These results suggested the great potential of LDPI-TOFMS platform for ascertain varieties of organic isomers which are not practically distinguished by other MS methods.

含氧多环芳烃 (OPAH) 是一种对人类和环境具有致突变性和普遍存在的污染物。区分其异构体的常规分析方法仍然存在挑战。在本文中，我们将激光解吸激光后电离飞行时间质谱 (LDPI-TOFMS) 作为表征 OPAH 异构体的新方法。这里，使用波长为532nm的脉冲激光解吸被另一波长为266nm的脉冲激光后电离的分析物。可以观察到 OPAH 之间准分子离子峰和特征峰的明显区分。我们已经证明，无论样品的极性和溶解度如何，LDPI-TOFMS 均可用于快速、清晰地区分异构体。此外，其他四种基于质谱 (MS) 的方法的结果也进行了比较，尽管它们无法区分异构体或无法获得分子离子峰。这些结果表明 LDPI-TOFMS 平台在确定其他 MS 方法实际上无法区分的各种有机异构体方面具有巨大潜力。