High time-resolution measurement of DMS and VOCs in seawater

在我们的平衡器进气-质子转移反应-质谱学技术中，未过滤的海水连续供应给平衡器，溶解的二甲基硫(DMS)被提取到鼓泡气体中，由质谱仪进行检测。为了研究使用未经过滤的海水可能产生的伪影及其影响的大小，我们在封闭的平衡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以硅藻为主的沿海海水样品中DMS的时间变化的影响。当未过滤的海水被氮气鼓泡时，DMS增加，但当它被空气鼓泡时，DMS增加，并且这种增加发生在平衡器中海水中的溶解氧耗尽之后。通过保持平衡器中的有氧条件，可以避免这种伪影，因此它将是极大地增加DMS浓度的有力工具。

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.