The photooxidation of dissolved organic matter in surface waters analyzed by Fourier-transform ion cyclotron resonance mass spectrometry.

Dissolved organic matter (DOM) plays an important role in carbon cycling in natural waters. The processing of DOM in these waters can occur via photooxidation, or interaction with sunlight. This processing can lead to the production of CO2, and also the alteration of organic compounds that make up DOM. It is likely that the extent of photooxidation is at least partially determined by the chemical composition of DOM. Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to characterize the dissolved organic matter at the molecular level for all water samples, both before and after light exposure to better understand the photooxidation of DOM. Chemical formulas were assigned to mass to generated mass to charge ratios using a custom script in R, resulting in a list of chemical formula assignments for each DOM sample, at multiple light exposure time points.

溶解态有机物（Dissolved Organic Matter, DOM）在天然水体的碳循环中发挥着关键作用。这类水体中的DOM转化过程可通过光氧化作用或与阳光的相互作用实现，该过程不仅会生成二氧化碳（CO₂），还会改变构成DOM的有机化合物组成。光氧化作用的程度大概率至少部分由DOM的化学组成所决定。
为深入解析DOM的光氧化过程，研究人员采用傅里叶变换离子回旋共振质谱（Fourier-transform Ion Cyclotron Resonance Mass Spectrometry, FT-ICR MS），在分子层面对所有光照处理前后的水体样品中的溶解态有机物进行了表征。研究人员借助R语言编写的自定义脚本，将分子式匹配至生成的质荷比数据，最终得到了多个光照时间点下每个DOM样品的分子式匹配结果列表。