Rizzarelli Paola, Puglisi Concetto, Montaudo Giorgio
Istituto di Chimica e Tecnologia dei Polimeri, Consiglio Nazionale delle Ricerche, V. le A. Doria 6, 95125 Catania, Italy.
Rapid Commun Mass Spectrom. 2006;20(11):1683-94. doi: 10.1002/rcm.2483.
Matrix-assisted laser desorption/ionization time-of-flight/time-of-flight tandem mass spectrometry (MALDI-TOF/TOF-MS/MS) was employed to analyze four poly(butylene adipate) (PBAd) oligomers and to investigate their fragmentation pathways as a continuation of our work on the MALDI-TOF/TOF-MS/MS study of synthetic polymers. MALDI-TOF/TOF-MS/MS analysis was performed on oligomers terminated by carboxyl and hydroxyl groups, methyl adipate and hydroxyl groups, dihydroxyl groups, and dicarboxyl groups. The sodium adducts of these oligomers were selected as precursor ions. Different end groups do not influence the fragmentation of sodiated polyester oligomers and similar series of product ions were observed in all the MALDI-TOF/TOF-MS/MS spectra. According to the structures of the most abundant product ions identified in the present work, three fragmentation pathways have been proposed to occur most frequently in PBAd: beta-hydrogen-transfer rearrangement, leading to the selective cleavage of the --O--CH(2)-- bonds; --CH(2)--CH(2)-- (beta--beta) bond cleavage in the adipate moiety; and ester bond scission.
作为我们对合成聚合物进行基质辅助激光解吸/电离飞行时间/飞行时间串联质谱（MALDI-TOF/TOF-MS/MS）研究工作的延续，采用MALDI-TOF/TOF-MS/MS分析了四种聚己二酸丁二醇酯（PBAd）低聚物，并研究了它们的碎裂途径。对以羧基和羟基、己二酸甲酯和羟基、二羟基以及二羧基封端的低聚物进行了MALDI-TOF/TOF-MS/MS分析。选择这些低聚物的钠加合物作为前体离子。不同的端基不影响钠化聚酯低聚物的碎裂，并且在所有MALDI-TOF/TOF-MS/MS谱图中均观察到类似系列的产物离子。根据本研究中鉴定出的最丰富产物离子的结构，提出了PBAd中最常发生的三种碎裂途径：β-氢转移重排，导致选择性断裂-O-CH(2)-键；己二酸酯部分中的-CH(2)-CH(2)-（β-β）键断裂；以及酯键断裂。
