High time-resolution measurement of DMS and VOCs in seawater

在我们的平衡器入口-质子转移反应-质谱技术中，将未过滤的海水连续供应到平衡器，并将溶解的二甲基硫醚（DMS）提取到鼓泡气体中并通过质谱检测。为了研究使用未过滤海水可能产生的伪影及其影响的大小，我们在平衡状态下的封闭系统中进行了实验室实验，重点研究了样品过滤和气体鼓泡对硅藻为主的沿海海水样品中DMS随时间变化的影响。DMS增加时，未过滤的海水鼓泡氮气，但不是当它鼓泡与空气，和增加发生后，溶解氧耗尽的海水中的平衡。这种人为因素可以通过维持平衡中的有氧条件来避免，因此它将是大大增加DMS浓度大小的有力工具。

In our equilibrator inlet-proton transfer reaction-mass spectrometry technique, unfiltered seawater is continuously supplied to the equilibrator, and dissolved dimethyl sulfide (DMS) is extracted into a bubbling gas and detected by the mass spectrometry. To investigate the possible artifact from using unfiltered seawater and the magnitude of its effects, we conducted laboratory experiments in a closed system at equilibrium, focusing on the effects of sample filtration and gas bubbling on the temporal variation of DMS in coastal seawater samples dominated by diatoms. DMS increased when unfiltered seawater was bubbled with nitrogen but not when it was bubbled with air, and the increase occurred just after dissolved oxygen was depleted in the seawater in the equilibrator. This artifact could be avoided by maintaining aerobic conditions in the equilibrator, and hence it will be a powerful tool to greatly increase the size of the DMS concentration.