Trimethylamine (TMA) is ubiquitous in the marine systems and may affect atmospheric chemistry as a precursor and strong stabilizer of atmospheric secondary aerosol, influencing cloud formation. Rapid and accurate measurement of the concentration of TMA in seawater is challenging due to their polarity, aqueous solubility, volatility and existence at low concentrations in marine environments. In this study, a dopant-assisted atmospheric pressure photoionization time-of-flight mass spectrometry (DA-APPI-TOFMS) coupled with a dynamic purge-release method was developed for rapid and sensitive analysis of TMA in seawater. A novel three-zones ionization source has been developed for improving the ionization efficiency of analyte molecules and minimizing the influence of high-humidity of the sample gas, which allowed direct analysis of high-humidity (RH> 90%) gas samples from microbubble purging process by the mass spectrometer. At atmospheric pressure, the three-zones ionization source allows the use of high-speed purge gas to quickly purge all organic amines dissolved in the water into the gas phase, ensuring quantitative accuracy. The limit of quantification (LOQ) for TMA down to 0.1 μg L-1 was obtained in less than 2 min by consuming only 2 mL seawater sample. This method was applied for the determination of the concentrations of TMA in the coastal seawater to validate its practicability and reliability for analysis of trace amines in marine environments.

中文翻译：

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使用动态吹扫释放和掺杂剂辅助大气压光电离质谱法快速、高灵敏度地测量海水中的三甲胺

三甲胺 (TMA) 在海洋系统中无处不在，作为大气二次气溶胶的前体和强稳定剂可能会影响大气化学，从而影响云的形成。由于 TMA 的极性、水溶性、挥发性和在海洋环境中以低浓度存在，因此快速准确地测量海水中 TMA 的浓度具有挑战性。在这项研究中，开发了一种掺杂剂辅助的大气压光电离飞行时间质谱 (DA-APPI-TOFMS) 与动态吹扫-释放方法相结合，用于快速、灵敏地分析海水中的 TMA。开发了一种新型的三区电离源，以提高分析物分子的电离效率，并最大限度地减少样气高湿的影响，这允许通过质谱仪直接分析来自微泡净化过程的高湿度 (RH> 90%) 气体样品。在大气压下，三区电离源允许使用高速吹扫气体将溶解在水中的所有有机胺快速吹扫到气相中，确保定量准确性。通过仅消耗 2 mL 海水样品，在不到 2 分钟的时间内即可获得低至 0.1 μg L-1 的 TMA 的定量限 (LOQ)。将该方法应用于沿海海水中TMA浓度的测定，验证了其分析海洋环境中痕量胺的实用性和可靠性。三区电离源允许使用高速吹扫气体将溶解在水中的所有有机胺快速吹扫到气相中，确保定量准确性。通过仅消耗 2 mL 海水样品，在不到 2 分钟的时间内即可获得低至 0.1 μg L-1 的 TMA 的定量限 (LOQ)。将该方法应用于沿海海水中TMA浓度的测定，验证了其分析海洋环境中痕量胺的实用性和可靠性。三区电离源允许使用高速吹扫气体将溶解在水中的所有有机胺快速吹扫到气相中，确保定量准确性。通过仅消耗 2 mL 海水样品，在不到 2 分钟的时间内即可获得低至 0.1 μg L-1 的 TMA 的定量限 (LOQ)。将该方法应用于沿海海水中TMA浓度的测定，验证了其分析海洋环境中痕量胺的实用性和可靠性。