Hecht Oliver, Ungethüm Bert, Walte Andreas, Lattouf Elie, Anttalainen Osmo, Kotiaho Tapio, Hakulinen Hanna, Eiceman Gary
AIRSENSE Analytics Gmbh, Hagenower Straße 73, Schwerin 19061, Germany.
VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, Helsinki, Florida FI-00014, Finland.
Anal Chem. 2024 Dec 17;96(50):19972-19980. doi: 10.1021/acs.analchem.4c04434. Epub 2024 Dec 4.
Rate coefficients () for the reactions of hydrated protons and a sample vapor (M) to form protonated monomers (MH(HO)) and proton bound dimers (MH) were determined simultaneously by using ion mobility spectrometry with a tandem drift tube at ambient pressure. In this method, sample vapors were introduced to a first drift region with stepwise reactions: M + H(HO) (HO) + ( - ) HO and M + MH (HO) MH + HO. Ions with a drift time between 9 and 18 ms in the first drift region were subsequently mobility analyzed in purified air with the second drift region using a synchronized second ion gate with boxcar averaging. Slope for plots of ion abundance against drift time was fitted by successive approximation between peaks of H(HO) and MH(HO) to obtain until computed and experimental slopes matched within a maximal deviation of 0.01. Values for were obtained from the experimental baseline slope when adjusted for . Rate coefficients for triethyl phosphate and phenylacetate were determined using this method with values of 1.14 × 10 ± 1.87 × 10 cm/s and 0.81 × 10 ± 9.26 × 10 cm/s and values of 1.05 × 10 ± 4.13 × 10 cm/s and 1.07 × 10 ± 1.86 × 10 cm/s, respectively. Relative error for this method was determined using mobility spectra generated with a COMSOL model and artificial rate coefficients. Rate coefficients were then extracted from the modeled mobility spectra and compared to the original artificial values. Relative error of this method was 10% and should be generally applicable for individual substances with reactions forming protonated monomers and proton bound dimers.
通过在环境压力下使用带有串联漂移管的离子迁移谱法，同时测定了水合质子与样品蒸气（M）反应形成质子化单体（MH(H₂O)）和质子键合二聚体（MH⁺）的速率系数（ ）。在该方法中，将样品蒸气引入到具有逐步反应的第一漂移区：M + H₃O⁺ (H₂O)⁺ + (M - H)H₂O 和 M + MH⁺(H₂O) MH₂⁺ + H₂O。随后，在第一漂移区中漂移时间在9至18毫秒之间的离子，使用带有箱式平均的同步第二离子门，在第二漂移区的净化空气中进行迁移率分析。通过在H₃O⁺(H₂O) 和 MH⁺(H₂O) 的峰之间进行逐次逼近，拟合离子丰度与漂移时间的关系图的斜率，以获得 ，直到计算得到的斜率和实验斜率在最大偏差0.01范围内匹配。 的值是在针对 进行调整后，从实验基线斜率获得的。使用该方法测定了磷酸三乙酯和苯乙酸酯的速率系数，其 值分别为1.14 × 10⁻¹³ ± 1.87 × 10⁻¹³ cm³/s 和 0.81 × 10⁻¹³ ± 9.26 × 10⁻¹⁴ cm³/s， 值分别为1.05 × 10⁻¹³ ± 4.13 × 10⁻¹⁴ cm³/s 和 1.07 × 10⁻¹³ ± 1.86 × 10⁻¹⁴ cm³/s。使用由COMSOL模型生成的迁移率谱和人工速率系数，确定了该方法的相对误差。然后从建模的迁移率谱中提取速率系数，并与原始人工值进行比较。该方法的相对误差为10%，通常应适用于通过形成质子化单体和质子键合二聚体的反应的单个物质。
