A quantification method for heat-decomposable methylglyoxal oligomers and its application on 1,3,5-trimethylbenzene SOA
A quantification method for heat-decomposable methylglyoxal oligomers and its application on 1,3,5-trimethylbenzene SOA
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DOI：
10.5194/acp-17-3929-2017
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发表时间：
2017-03
影响因子：
6.3
通讯作者：
M. Rodigast;A. Mutzel;H. Herrmann
中科院分区：
文献类型：
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作者：
M. Rodigast;A. Mutzel;H. Herrmann
抽象的。丙酮醛在大气水相颗粒物中形成低聚化合物，这可能对含水二次有机气溶胶（aqSOA）的形成有重要贡献。到目前为止，没有合适的方法来定量的甲基乙二醛低聚物是可用的，尽管花了很大的努力，结构解析。在本研究中，开发了一种简化的方法来量化热分解的甲基乙二醛低聚物作为一个总和参数。该方法是基于低聚物热分解成甲基乙二醛单体。使用PFBHA（邻-（2，3，4，5，6-五氟苄基）羟胺盐酸盐）衍生化和气相色谱-质谱（GC/MS）分析检测形成的甲基乙二醛单体。该方法开发的重点是加热时间（在15和48小时之间变化），加热过程中的pH值（pH = 1 - 7）和加热温度（50，100 ° C）。这些方法参数的优化值。所开发的方法被应用于量化的1，3，5-三甲基苯（TMB）在莱比锡气溶胶室（LEipziger AerosolKammer，LEAK）的OH-自由基氧化过程中形成的热分解甲基乙二醛低聚物。低聚物的形成作为种子颗粒的酸度和相对湿度的函数进行了研究。在所产生的有机颗粒质量中发现高达8%的可热分解的丙酮醛低聚物的分数，突出了仅由丙酮醛形成的那些低聚物对于SOA形成的重要性。总体而言，本研究提供了一种新的和合适的方法，用于定量的热分解甲基乙二醛低聚物在水颗粒相。
Abstract. Methylglyoxal forms oligomeric compounds in the atmospheric aqueous particle phase, which could establish a significant contribution to the formation of aqueous secondary organic aerosol (aqSOA). Thus far, no suitable method for the quantification of methylglyoxal oligomers is available despite the great effort spent for structure elucidation. In the present study a simplified method was developed to quantify heat-decomposable methylglyoxal oligomers as a sum parameter. The method is based on the thermal decomposition of oligomers into methylglyoxal monomers. Formed methylglyoxal monomers were detected using PFBHA (o-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride) derivatisation and gas chromatography–mass spectrometry (GC/MS) analysis. The method development was focused on the heating time (varied between 15 and 48 h), pH during the heating process (pH = 1–7), and heating temperature (50, 100 °C). The optimised values of these method parameters are presented. The developed method was applied to quantify heat-decomposable methylglyoxal oligomers formed during the OH-radical oxidation of 1,3,5-trimethylbenzene (TMB) in the Leipzig aerosol chamber (LEipziger AerosolKammer, LEAK). Oligomer formation was investigated as a function of seed particle acidity and relative humidity. A fraction of heat-decomposable methylglyoxal oligomers of up to 8 % in the produced organic particle mass was found, highlighting the importance of those oligomers formed solely by methylglyoxal for SOA formation. Overall, the present study provides a new and suitable method for quantification of heat-decomposable methylglyoxal oligomers in the aqueous particle phase.