Characterization of the chemical composition of a block copolymer by liquid chromatography/mass spectrometry using atmospheric pressure chemical ionization and electrospray ionization

Abstract

Liquid chromatography/mass spectrometry (LC/MS) with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) in the positive and negative ion modes was used for the characterization of a block copolymer consisting of methoxy poly(ethylene oxide) (mPEO), an epsilon-caprolactone (CL) segment and linoleic acid (LA), used as surfactant in water-based latex paints. Chromatographic separation was obtained based on the number of CL units in the polymer species and the presence of an mPEO and/or LA tail. Different ionization methods were found to be complementary and only their combination allowed the qualitative profiling of the chemical composition. The LC/MS method has proven valuable for following the reaction in time, as well as for comparison of different polymeric surfactants.

APCI/APPI for synthetic polymer analysis

“…However, the corresponding LC/APCI-MS signal was very minor compared to the methyl-terminated polymer (Schneider, Sablier, & Desmazieres, 2008). Similarly, the analyses by van Leeuwen et al (2007) of a complex mixture displayed totally different abundance ratios with different ionization methods (ESI and APCI in positive-and negative-ion modes); these results highlight the lack of correlation between actual abundance and MS intensity. Therefore, the problem of relative quantification must be addressed with care on an individual basis.…”

“…Finally, Harrison et al (1997) If APCI detection is more efficient than ESI for some compounds, then the opposite can also be true. Van Leeuwen et al used LC/MS to characterize a block copolymer consisting of methoxy poly(ethylene oxide) (mPEO) and a e-caprolactone segment (pCL) (van Leeuwen et al, 2007). ESI and APCI, each in the negative-and positive-ion modes were compared.…”

Soft ionization mass spectroscopy: Insights into the polymerization mechanism

“…Instrument parameter settings can also play an important role in successful mass spectrometry measurement with parameters such as laser pulse rate, mass range, accelerating voltage, reflectron/linear mode (MALDI), and capillary voltage, spray voltage, capillary temperature (in the case of ESI) all shown to have dramatic impacts on the quality of MS spectra acquisition. Importantly, there have been recent advances in adding front‐end separation technology, such as HPLC or GPC to both ESI and MALDI systems 66–69. The hyphenated systems substantially increase MS analytical power following a reduction in the polymer distribution prior to analysis.…”

Mass Spectroscopy in Polymer Research

“…The following protocol describes a mass spectrometric method for characterization of a block copolymer consisting of methoxy poly(ethylene oxide) ( mPEO ), an ε -caprolactone ( CL ) segment, and linoleic acid ( LA ), used as surfactant in water -based latex paints by liquid chromatography electrospray ionization (LC -ESI) or API -MS [10] .…”