海水中痕量DMS和DMSP分析方法的研究

AN ANALYTICAL METHOD OF DETERMINING TRACE QUANTITIES OF DIMETHYLSULFIDE AND DIMETHYLSULFONIOPROPIONATE IN SEAWATER

二甲基硫(DMS)是海洋排放的占优势地位的生源硫气体,其在大气中的氧化产物能够影响到环境酸化和世界的气候变化。因此,测定海水中的DMS对于准确地评价其在全球硫循环所起的重要作用具有重要意义。本文中作者研究了海水中DMS的痕量分析技术。海水中的DMS首先采用气提-冷阱捕集技术进行预浓缩,然后用带有火焰光度检测器的气相色谱(GC-FPD)进行分析。该方法的精确度在5%以内,平均回收率为85.6%(82.8%—90.5%),最小检出限为0.15ngS。β-二甲基巯基丙酸内盐(DMSP)的分析是通过将其在碱性溶液中分解成DMS来进行。作者采用此方法实测了黄海中DMS和DMSP的含量,获得了理想的结果。

Dimethylsulfide （DMS） is a dominant biogenic sulfur gas emanating from the oceans. The oxidation products of DMS in atmosphere can affect environmental acidification and the world＇s climate. Therefore, determining DMS in seawater is important for understanding the role of DMS in global sulfur cycling. An analytical technique determining trace quantities of DMS in seawater is presented in this paper. DMS in seawater was pre-concentrated with purge-and-trap technique and then analyzed by a gas chromatographer equipped with sulfur specific flame photometric detector. Precision for the analysis of DMS was within 5%. The average recovery of DMS was 85.6% （82.8%-90.5%）. The detection limit for DMS was 0.15 ng S. Dimethylsulfoniopropionate （DMSP） was analyzed after alkaline cleavage to DMS in 1：1 stoichiometry. We used this method to measure in situ DMS and DMSP concentrations in the Yellow Sea and obtained reasonable results.