Analysis of free fatty acids by ultraviolet laser desorption ionization mass spectrometry using insect wings as hydrophobic sample substrates.
Analysis of free fatty acids by ultraviolet laser desorption ionization mass spectrometry using insect wings as hydrophobic sample substrates.
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DOI：
10.1021/ac5020047
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发表时间：
2014-10
影响因子：
7.4
通讯作者：
A. Pirkl;M. Meier;Yulia Popkova;M. Letzel;A. Schnapp;J. Schiller;K. Dreisewerd
中科院分区：
文献类型：
--
作者：
A. Pirkl;M. Meier;Yulia Popkova;M. Letzel;A. Schnapp;J. Schiller;K. Dreisewerd
通过紫外激光解吸/电离正交萃取飞行时间质谱（LDI-oTOF-MS）分析生理相关的游离脂肪酸（FFA）。从果蝇的果蝇被解剖的翅膀被用作疏水的，强吸收激光能量的样品基板。使用未处理的底物主要产生FFA的分子[M + K]（+）离子，而其他碱金属加合物可以通过在点样分析物之前用相应的碱金属氢氧化物处理翼来产生。正离子模式的检测限被确定为分离的游离脂肪酸的混合物中的低10 pmol范围内的值。具体值取决于链长和不饱和度。如果加入内标物（15：0 FFA），饱和FFA分析的R（2）系数在约3个数量级上通常接近0.98。含有不饱和游离脂肪酸的混合物的半定量分析也是可能的，但需要更多的努力校准策略。值得注意的是，饱和和（多）不饱和脂肪酸的检测灵敏度相对较高浓度的其他生理丰富的脂质（磷脂和三环甘油）的存在下。这简化了粗组织提取物中FFA组成的筛选。这一特点是证明了由粗肝提取物和指纹的分析。
Physiologically relevant free fatty acids (FFAs) were analyzed by UV-laser desorption/ionization orthogonal extracting time-of-flight mass spectrometry (LDI-oTOF-MS). Dissected wings from Drosophila melanogaster fruit flies were used as the hydrophobic, laser energy strongly absorbing sample substrates. Using untreated substrates produces predominantly molecular [M + K](+) ions of the FFAs, whereas other alkali metal adducts can be generated by treating the wings with the corresponding alkali hydroxide before spotting of analyte. Limits of detection for the positive ion mode were determined for mixtures of isolated FFAs to values in the low 10 pmol range. Specific values depend on chain length and degree of unsaturation. R(2) coefficients for the analysis of saturated FFAs were found to be generally close to 0.98 over about 3 orders of magnitude if an internal standard (15:0 FFA) was added. Semiquantitative analyses of mixtures containing unsaturated FFAs are also possible but require more effort on the calibration strategy. Notably, both saturated and (poly-)unsaturated FFAs are detected sensitively in the presence of relatively high concentrations of other physiologically abundant lipids (phospholipids and triacyclglycerols). This simplifies screening of the FFA composition in crude tissue extracts. This feature is demonstrated by the analysis of a crude liver extract and that of fingermarks.