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Characterization of linear and cyclic polylactic acids and their solvolysis products by electrospray ionization mass spectrometry
Author(s) -
Osaka Issey,
Watanabe Mikio,
Takama Masashi,
Murakami Masahiro,
Arakawa Ryuichi
Publication year - 2006
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.1110
Subject(s) - chemistry , solvolysis , mass spectrometry , electrospray ionization , polylactic acid , electrospray , characterization (materials science) , chromatography , thermospray , organic chemistry , tandem mass spectrometry , selected reaction monitoring , hydrolysis , nanotechnology , polymer , materials science
Linear and cyclic polylactic acids (PLAs) were characterized using electrospray ionization mass spectrometry (ESI‐MS) as part of our ongoing investigation of the hydrolysis mechanism of biodegradable polymers. The condensation oligomers of linear polylactic acid (LPLA) were synthesized by thermal dehydration of L ‐lactic acid. The trimer and tetramer base polymers of cyclic polylactic acid (CPLA) were obtained by cyclization reactions of lactic acid trimers and tetramers, respectively. In the ESI‐MS/MS measurement, LPLA yielded three types of product ion series, while CPLA yielded only one type, from which the repeated units of CPLA were removed. The MS/MS spectrum of the NH 4 + adduct ion for both cyclic and linear PLA showed loss of one ammonia molecule. The postsource decay (PSD) spectrum of CPLA by matrix‐assisted laser desorption ionization (MALDI) mass spectrometry was similar to the ESI‐MS/MS spectrum, while that of LPLA was different. In addition, the degradation of cyclic and linear PLAs by solvolysis was investigated. Solvolysis with anhydrous MeOH was quite feasible, but did not readily occur in the presence of even a small amount of water in the MeOH solvent. Copyright © 2006 John Wiley & Sons, Ltd.