Mize Todd H, Simonsick William J, Amster I Jonathan
FOM Institute of Atomic & Molecular Physics, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands.
Eur J Mass Spectrom (Chichester). 2003;9(5):473-86. doi: 10.1255/ejms.571.
Two homopolyesters, poly(neopentyl glycol-alt-isophthalic acid) and poly(hexanediol-alt-azelaic acid), and two copolyesters, poly(dipropoxylated bisphenol-A-alt-(isophthalic acid-co-adipic acid)) and poly(neopentyl glycol-alt-(adipic acid-co-isophthalic acid)) were analyzed by internal source matrix assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS). The high resolution and high mass accuracy provided by FTMS greatly facilitate the characterization of the polyester and copolyester samples. Isobaric resolution allows the ion abundances of overlapping isotopic envelopes to be assessed. Repeat units were confirmed and end functionality assigned. Single shot mass spectra of the entire polymeric distribution demonstrate that the dynamic range of this internal MALDI source instrument and the analyzer cell exceeds performance of those previously reported for higher field instruments. Corrections of space charge mass shift effects are demonstrated for the analytes using an external calibrant and (subsequent to confirmation of structure) via internal calibration which removes ambiguity due to space charge differences in calibrant and analyte spectra. Capillary gel permeation chromatography was used to prepare low polydispersity samples from a high polydispersity polyester, improving the measurement of molecular weight distribution two-fold while retaining the benefits of high resolution mass spectrometry for elucidation of oligomer identity.
采用内源性基质辅助激光解吸/电离傅里叶变换质谱法（MALDI-FTMS）对两种均聚酯（聚（新戊二醇-alt-间苯二甲酸）和聚（己二醇-alt-壬二酸））以及两种共聚酯（聚（二丙氧基化双酚A-alt-（间苯二甲酸-co-己二酸））和聚（新戊二醇-alt-（己二酸-co-间苯二甲酸）））进行了分析。傅里叶变换质谱仪提供的高分辨率和高质量精度极大地促进了聚酯和共聚酯样品的表征。等压分辨率使得重叠同位素包络的离子丰度得以评估。确认了重复单元并确定了端基官能团。整个聚合物分布的单次质谱表明，这种内源性MALDI源仪器和分析池的动态范围超过了先前报道的高场仪器的性能。使用外部校准物对分析物的空间电荷质量位移效应进行了校正，并（在结构确认之后）通过内部校准进行校正，这消除了由于校准物和分析物光谱中的空间电荷差异而产生的歧义。采用毛细管凝胶渗透色谱法从高多分散性聚酯制备低多分散性样品，在保留高分辨率质谱用于阐明低聚物身份的优点的同时，将分子量分布的测量提高了两倍。
