The detection limits and photoionization thresholds of polycyclic aromatic hydrocarbons and their chlorides and nitrides on the water surface are examined using laser two-photon ionization and single-photon ionization, respectively. The laser two-photon ionization methods are highly surface-selective, with a high sensitivity for aromatic hydrocarbons tending to accumulate on the water surface in the natural environment due to their highly hydrophobic nature. The dependence of the detection limits of target aromatic molecules on their physicochemical properties (photoionization thresholds relating to excess energy, molar absorptivity, and the octanol–water partition coefficient) is discussed. The detection limit clearly depends on the product of the octanol–water partition coefficient and molar absorptivity, and no clear dependence was found on excess energy. The detection limits of laser two-photon ionization for these types of molecules on the water surface are formulated.

中文翻译：

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激光和同步加速器辐射使水表面上环境污染的芳族氯化物和氮化物光电离

使用激光两光子电离和单光子电离分别检测水表面上多环芳烃及其氯化物和氮化物的检出限和光电离阈值。激光二光子电离方法具有高度的表面选择性，对芳香烃由于其高度疏水性而倾向于在自然环境中积聚在水表面的敏感性很高。讨论了目标芳香分子的检出限对其理化性质（与过量能量​​，摩尔吸光度和辛醇-水分配系数有关的光电离阈值）的依赖性。检出限明显取决于辛醇-水分配系数与摩尔吸收率的乘积，并没有发现对过量能量的明确依赖。针对水表面上这些类型的分子，制定了激光双光子电离的检测限。