Detailed analysis of α,ω-bis(4-hydroxybutyl) poly(dimethylsiloxane) using GPC-MALDI TOF mass spectrometry

Maziarz, E. Peter; Liu, X. Michael; Quinn, Edmond T.; Lai, Yu‐Chin; Ammon, Daniel M.; Grobe, George L.

doi:10.1016/s1044-0305(01)00347-6

Cited by 25 publications

(18 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In some cases, certain ions may be artifacts due to the gas-phase fragmentation processes, thus applying softer ionization conditions should help reduce or even eliminate these artifacts. In other cases, certain ions could be due to real impurities in the analyte and designed derivatization experiments should help confirm their structures [21,22]. …”

Section: Discussionmentioning

confidence: 99%

“…A minor series of ions corresponding to hydroxy terminated polymers were observed and a hydrogen exchange fragmentation mechanism was proposed (Scheme 1). Shortly after, Maziarz et al reported another study of an ␣, -bis(4-hydroxybutyl) polydimethysiloxane (HB-PDMS) and oligomers end capped with one hydroxy end group were also observed [22]. A different mechanism (backbiting mechanism) was proposed for the latter case, in contrast to the mechanism proposed for the former case.…”

mentioning

confidence: 98%

See 1 more Smart Citation

Endgroup-assisted siloxane bond cleavage in the gas phase

Chen

2003

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

ϩ . The formation of SiC 5 H 16 NO ϩ involves dissociation of a Si™O bond and formation of an O™H bond through rearrangement. The fragmentation mechanism was investigated utilizing ab initio calculations and Fourier transform ion cyclotron resonance (FTICR) mass spectrometry in combination with hydrogen/deuterium (H/D) exchange reactions. Sustained off-resonance irradiation collision-induced dissociation (SORI-CID) studies of the fully deuterated ion D 2 N(CH 2 ) 3 SiOSi(CH 2 ) 3 ND 3 ϩ provided convincing evidence for a backbiting mechanism which involves hydrogen transfer from the terminal amine group to the oxygen to form a silanol-containing species. Theoretical calculations indicated decomposition of H 2 N(CH 2 ) 3 SiOSi(CH 2 ) 3 NH 3 ϩ through a backbiting mechanism is the lowest energy decomposition channel, compared with other alternative routes. Two mechanisms were proposed for the fragmentation process which leads to the siloxane bond cleavage and the SORI-CID results of partially deuterated precursor ions suggest both mechanisms should be operative. Rearrangement to yield a silanol-containing product ion requires end groups possessing a labile hydrogen atom. Decomposition of disiloxane ions with end groups lacking labile hydrogen atoms yielded product ions from direct bond cleavages. (J

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 98%

Endgroup-assisted siloxane bond cleavage in the gas phase

Chen

2003

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

show abstract

“…he advent of soft ionization techniques such as matrix-assisted laser desorption ionization (MALDI) and electrospray ionization (ESI) have provided chemists the ability to evaluate polymer samples with several different mass analyzers. Specifically for polysiloxane materials the information rich data obtained from such analysis has been used qualitatively for repeat unit and end group determination [1][2][3][4][5][6][7] and quantitatively for relative concentration [8,9] and average mass determination [10,11]. Several reviews appear in the literature that highlight many of the applications of polymer mass spectrometry analysis [12][13][14][15].…”

mentioning

confidence: 99%

“…Several research groups have illustrated the powerful combination of GPC with MALDI and ESI MS for polymer analysis. In the most traditional sense, GPC can be incorporated by manually collecting GPC fractions in a number of vials for subsequent analysis by ESI [23,31] or MALDI MS [5,6,10,11,23,[32][33][34][35][36]. This approach is relatively time consuming and very tedious since each collected GPC mass fraction requires sample preparation prior to MS analysis.…”

mentioning

confidence: 99%

Comparative studies of poly(dimethyl siloxanes) using automated GPC-MALDI-TOF MS and on-line GPC-ESI-TOF MS

Liu¹,

Maziarz²,

Heiler³

et al. 2003

J. Am. Soc. Mass Spectrom.

Self Cite

View full text Add to dashboard Cite

In this study we compare on-line gel permeation chromatography (GPC) electrospray ionization (ESI) time-of-flight (TOF) mass spectrometry (MS) to automated GPC matrix assisted laser desorption ionization (MALDI) TOF MS for poly (dimethylsiloxane) (PDMS) analysis. Average mass values for a hydroxyl-terminated PDMS (OH-PDMS) sample were obtained and compared to traditional GPC that was calibrated with narrow polystyrene standards, by direct ESI and MALDI MS analysis, by a summation of mass spectra of all GPC fractions, and also by the recalibration method determined by both mass spectrometric methods. Quantitatively, the difference noted here between these hyphenated techniques is that GPC-ESI-TOF MS effectively reports the low-mass oligomers and underestimates the high-mass oligomers, while GPC-MALDI-TOF MS effectively reports the high-mass oligomers and underestimates the low-mass oligomers. In the GPC-ESI-TOF MS experiments, ion current suppression was observed in the high molecular weight region. The suppression effect was confirmed by repeatable sample runs and by injecting different PDMS samples. Higher chromatographic resolution was observed for GPC-ESI-TOF MS compared to GPC-MALDI-TOF MS. In fact, truly mono-disperse oligomers were observed in the low molecular weight range from GPC-ESI MS experiments. (J

show abstract

“…Overall, the spectrum had a similar appearance to that of its coordination complex (see below and Supporting Information) in that the peak separations (74 mass units), their intensities and isotope patterns are typical for monodisperse PDMS chains. [7] Such monodisperse chains will have a narrow polydispersity (between 1.1 and 1.5), where polydispersity is the ratio of M w :M n (M w = weight average molecular weight and gives greater statistical weighting to heavier molecules, M n = number average molecular weight and gives greater statistical weighting to lighter molecules). When polydispersity is 1.0, all of the polymer chains will be of exactly the same weight and length.…”

Section: Preliminary Studies Using L1mentioning

confidence: 99%