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Matrix‐assisted laser desorption/ionization, fast atom bombardment and plasma desorption mass spectrometry of polyethylene glycol esters of (2‐benzothiazolon‐3‐yl)acetic acid
Author(s) -
Mincheva Zoia,
Hadjieva Petia,
Kalcheva Veneta,
Seraglia Roberta,
Traldi Piero,
Przybylski Michael
Publication year - 2001
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.162
Subject(s) - chemistry , mass spectrum , adduct , fast atom bombardment , mass spectrometry , dispersity , desorption , analytical chemistry (journal) , ion , polyatomic ion , ionization , polymer chemistry , chromatography , organic chemistry , adsorption
Fast atom bombardment (FAB), matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) and plasma desorption (PD) mass spectra of newly synthesized polyethylene glycols (PEGs), ( M w 600–4000 Da) chemically modified with biologically active (2‐benzothiazolon‐3‐yl)acetyl end‐groups are described (products 1 – 6 ). The spectra were also used for the determination of the molecular mass characteristics (number average ( M n ) and weight average ( M w ) molecular masses) of the initial and modified PEGs. As expected, M n and M w of the modified samples are higher than those of the nonmodified samples. However, it is shown that molecular mass dispersity (determined by the comparison of the polydispersity indices ( PDI = M w / M n ) of both types of PEGs) essentially do not change during this modification. The FAB mass spectra, together with molecular species, show the presence of abundant [M + Na] + ions of product 1 and [M + Na + H] + species of 2 and 3 , and [M + Na + 2H] + of product 4 . Two main series of fragment ions, derived from the cleavage of the ether bonds, are observed. The number fractions of the molecular adduct ions and fragment adduct ions, determined from the FAB and PD mass spectra of the modified PEGs, are compared. The MALDI‐TOF mass spectra of compounds 1 – 6 show the presence of two series of polymers. The most abundant peaks are due to [M + Na] + and [M + K] + ions originating from the polymers, in which the two terminal hydroxyl groups of PEGs are esterified with (2‐benzothiazolon‐3‐yl)acetic acid. The less abundant peaks are due to the monosubstituted polymers. Copyright © 2001 John Wiley & Sons, Ltd.