Carbon-carbon double bond position elucidation in fatty acids using ozone-coupled direct analysis in real time mass spectrometry
Carbon-carbon double bond position elucidation in fatty acids using ozone-coupled direct analysis in real time mass spectrometry
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DOI：
10.1039/c9an01059a
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发表时间：
2019-10-07
期刊：
影响因子：
4.2
通讯作者：
Yew, Joanne Y.
中科院分区：
文献类型：
--
作者：
Cetraro, Nicolas;Cody, Robert B.;Yew, Joanne Y.
不饱和脂肪酸的碳-碳双键位置可以对生物功能产生明显不同的影响，也可以作为疾病病理学、饮食史和物种身份的生物标志物。因此，人们对开发用于天然产物化学、制药工业和法医学的双键位置的简便测定方法有很大的兴趣。我们配对臭氧分解与直接分析在真实的时间质谱（DART MS）裂解和快速确定碳-碳双键的位置在脂肪酸，脂肪醇，蜡酯，和粗脂肪酸提取物。此外，臭氧暴露时间和DART离子源温度进行了研究，以确定最佳条件。我们的研究结果表明，短暂的，离线暴露于臭氧产生的醛和羧酸盐的产品是指示碳-碳双键的位置。诊断片段的相对丰度定量地反映了混合物中同量异位脂肪酸位置异构体的比率，相关系数为0.99。最后，由未分级脂肪酸提取物产生的不饱和度谱可用于区分昆虫物种和种群。通过臭氧分解与DART MS相结合快速阐明脂质双键位置的能力将有助于脂质结构阐明，评估等压纯度，并可能区分饲喂不同饮食或属于不同生态种群的动物。
The carbon-carbon double bond positions of unsaturated fatty acids can have markedly different effects on biological function and also serve as biomarkers of disease pathology, dietary history, and species identity. As such, there is great interest in developing methods for the facile determination of double bond position for natural product chemistry, the pharmaceutical industry, and forensics. We paired ozonolysis with direct analysis in real time mass spectrometry (DART MS) to cleave and rapidly identify carbon-carbon double bond position in fatty acids, fatty alcohols, wax esters, and crude fatty acid extracts. In addition, ozone exposure time and DART ion source temperature were investigated to identify optimal conditions. Our results reveal that brief, offline exposure to ozone-generated aldehyde and carboxylate products that are indicative of carbon-carbon double bond position. The relative abundance of diagnostic fragments quantitatively reflects the ratios of isobaric fatty acid positional isomers in a mixture with a correlation coefficient of 0.99. Lastly, the unsaturation profile generated from unfractionated, fatty acid extracts can be used to differentiate insect species and populations. The ability to rapidly elucidate lipid double bond position by combining ozonolysis with DART MS will be useful for lipid structural elucidation, assessing isobaric purity, and potentially distinguishing between animals fed on different diets or belonging to different ecological populations.