Chemical Analysis of Complex Organic Mixtures Using Reactive Nanospray Desorption Electrospray Ionization Mass Spectrometry
Chemical Analysis of Complex Organic Mixtures Using Reactive Nanospray Desorption Electrospray Ionization Mass Spectrometry
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DOI：
10.1021/ac301533z
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发表时间：
2012-08-21
影响因子：
7.4
通讯作者：
Laskin, Alexander
中科院分区：
文献类型：
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作者：
Laskin, Julia;Eckert, Peter A.;Laskin, Alexander
采用反应性纳米喷雾解吸电喷雾电离（nano-DESI）结合高分辨质谱技术对柠檬烯臭氧分解（LSOA）产生的二次有机气溶胶进行分析。以往的研究表明，LSOA的成分是多功能的化合物，含有至少一个醛或酮基团。在这项研究中，我们使用的选择性的吉拉德的试剂T（GT）对羰基化合物的反应性纳米DESI的分析复杂的有机混合物的效用进行了研究。在这些实验中，使用1-100 μ M GT溶液作为反应性纳米DESI分析的工作溶剂。在GT浓度超过10 μ M时，观察到从单一添加GT到LSOA组分的丰富产物。我们发现LSOA二聚体和三聚体化合物与GT通过简单的加成反应形成甲醇胺衍生物。相反，GT与单体物质的反应导致甲醇胺和腙衍生物的形成。此外，在我们实验的时间范围内，有几种单体没有与GT反应。这些分子的特征在于相对高的双键当量值和低的氧含量。此外，由于向中性分子中添加带电荷的GT标签消除了电离过程中对低质子亲和力化合物的区分，因此反应性纳米DESI分析能够定量复杂混合物中的单个化合物。例如，我们能够第一次估计LSOA混合物中二聚体和三聚体的数量。具体而言，我们发现，最丰富的LSOA二聚体检测到在类似于0.5 pg的水平和分析样品中的二聚体和三聚体的总量是类似于11 pg。我们的研究结果表明，反应性纳米DESI是一个有价值的方法，用于检查特定的官能团的存在下，并具有这些基团的化合物的量化复杂的混合物。
Reactive nanospray desorption electrospray ionization (nano-DESI) combined with high-resolution mass spectrometry was utilized for the analysis of secondary organic aerosol produced through ozonolysis of limonene (LSOA). Previous studies have shown that LSOA constituents are multifunctional compounds containing at least one aldehyde or ketone groups. In this study, we used the selectivity of the Girard's reagent T (GT) toward carbonyl compounds to examine the utility of reactive nano-DESI for the analysis of complex organic mixtures. In these experiments, 1-100 mu M GT solutions were used as the working solvents for reactive nano-DESI analysis. Abundant products from the single addition of GT to LSOA constituents were observed at GT concentrations in excess of 10 mu M. We found that LSOA dimeric and trimeric compounds react with GT through a simple addition reaction resulting in formation of the carbinolamine derivative. In contrast, reactions of GT with monomeric species result in the formation of both the carbinolamine and the hydrazone derivatives. In addition, several monomers did not react with GT on the time scale of our experiment. These molecules were characterized by relatively high values of the double bond equivalent and low oxygen content. Furthermore, because addition of a charged GT tag to a neutral molecule eliminates the discrimination against the low proton affinity compounds in the ionization process, reactive nano-DESI analysis enables quantification of individual compounds in the complex mixture. For example, we were able to estimate for the first time the amounts of dimers and trimers in the LSOA mixture. Specifically, we found that the most abundant LSOA dimer was detected at the similar to 0.5 pg level and the total amount of dimers and trimers in the analyzed sample was similar to 11 pg. Our results indicate that reactive nano-DESI is a valuable approach for examining the presence of specific functional groups and for the quantification of compounds possessing these groups in complex mixtures.