Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland.
Anal Chem. 2010 Jan 1;82(1):323-8. doi: 10.1021/ac9020006.
We report systematic studies of solvent-free modification of matrix-assisted laser desorption/ionization time-of-flight (SF MALDI-TOF) mass spectrometry in analysis of synthetic polymers employing solid-state NMR spectroscopy as a supporting technique. In the present work oligomeric (M(n) = 4000 g mol(-1)) poly(L-lactide) (PLLA) was employed as a reference sample. The analyte was embedded into four matrixes commonly used in MALDI-TOF analysis of polymers: 1,8-dihydroxy-9-anthracenone (DT), 2,5-dihydroxybenzoic acid (DHB), 2-(4 hydroxyphenylazo)-benzoic acid (HABA), and trans-3-indoleacrylic acid (IAA). Solid-state NMR measurements clearly showed that the initial crystallinity of PLLA had no influence on quality of SF MALDI-TOF spectra since the crystalline structure of the analyte was not preserved during analyte/matrix grinding. Interestingly, the matrix remained crystalline during the sample's preparation. It was also found that, on the contrary to the dried droplet (DD) method, the SF approach leads to highly resolved mass spectra for a large variety of matrixes. Finally, problems of polymorphism and mechanochemical processes that can occur during the analyte/matrix grinding are briefly discussed.
我们报告了无溶剂基质辅助激光解吸/电离飞行时间（SF MALDI-TOF）质谱法在采用固态 NMR 光谱学作为辅助技术分析合成聚合物中的系统研究。在本工作中，使用低聚物（M(n) = 4000 g mol(-1)）聚 L-丙交酯（PLLA）作为参比样品。将分析物嵌入到四种常用于聚合物 MALDI-TOF 分析的基质中：1,8-二羟基-9-蒽酮（DT）、2,5-二羟基苯甲酸（DHB）、2-（4-羟基苯基偶氮）-苯甲酸（HABA）和反式-3-吲哚丙烯酸（IAA）。固态 NMR 测量清楚地表明，PLLA 的初始结晶度对 SF MALDI-TOF 光谱的质量没有影响，因为在分析物/基质研磨过程中，分析物的晶体结构没有被保留。有趣的是，基质在样品制备过程中保持结晶状态。还发现，与干液滴（DD）方法相反，SF 方法可针对各种基质得到高度分辨的质谱。最后，简要讨论了在分析物/基质研磨过程中可能发生的多晶型和机械化学过程的问题。
