The present study reports the first evaluation of a MIMS device equipped with a high-resolution Fourier transform-ion cyclotron resonance mass spectrometer (FT-ICR MS) for comprehensive speciation of chlorine-produced oxidants (CPO) in seawater. A total of 40 model compounds were studied: 4 inorganic haloamines (mono-, di-, and trichloramine and monobromamine), 22 organic N-haloamines, 12 N-haloamino acids, and 2 free oxidants (HOCl/ClO⁻ and HOBr/BrO⁻). The main key factors influencing the analytes’ introduction and their detection were optimized. Under optimized conditions, the rise and fall times of the MIMS signal ranged from 8 to 79 min and from 7 to 73 min, respectively, depending on the compound. Free oxidants and N-haloamino acids, which are ionic or too polar at seawater pH, hardly crossed the membrane, and MIMS analysis was thus unsuitable. Nevertheless, better enrichment and therefore better sensitivity were achieved with organic N-haloamines than with inorganic haloamines. The observed detection limits ranged from tens of μM to sub-μM levels. Oxidant decomposition occurred inside the MIMS device, at a higher rate for N-bromamines than for chlorinated analogues.

Graphical abstract

本研究报告首次对配备了高分辨率傅里叶变换离子回旋共振质谱仪（FT-ICR MS）的MIMS设备进行了评估，以对海水中的氯生成氧化剂（CPO）进行全面的形态分析。总共40种模型化合物进行了研究：4个无机卤代胺（单，二，和三氯胺和monobromamine），22有机的N-卤代胺，12 N-haloamino酸和2和自由氧化剂（次氯酸/ CLO ^-和次溴酸/的BrO ^-）。优化了影响分析物引入和检测的主要关键因素。在最佳条件下，根据化合物的不同，MIMS信号的上升和下降时间分别为8到79分钟和7到73分钟。游离氧化剂和N-卤代氨基酸在海水pH值下是离子性或极性太强，几乎不会穿过膜，因此MIMS分析是不合适的。然而，与无机卤代胺相比，有机N-卤代胺实现了更好的富集，因此灵敏度更高。观察到的检测极限范围从几十μM到亚μM。在MIMS设备内部发生了氧化剂分解，N-溴胺的分解速率高于氯化类似物。

图形概要