Mwf. Nielen, CHARACTERIZATION OF SYNTHETIC-POLYMERS BY SIZE-EXCLUSION CHROMATOGRAPHY ELECTROSPRAY-IONIZATION MASS-SPECTROMETRY, Rapid communications in mass spectrometry, 10(13), 1996, pp. 1652-1660
Size-exclusion chromatography/electrospray ionization mass spectrometr
y (SEC/ESI-MS) was studied for the characterization of polydisperse sy
nthetic polymers having different polarities. Reconstructed-ion curren
ts and the number of oligomers observed were found to depend strongly
on both the level of cationization salt and the cone voltage setting,
with the less polar polymers requiring a higher salt concentration in
the tetrahydrofuran mobile phase. The polymers, poly(tetrahydrofuran),
poly(methylmethacrylate), polyester and poly(styrene) were characteri
zed in terms of repeating units and end-groups and used to compute acc
urate calibration curves for the SEC column. Thus the on-line SEC/ESI-
MS approach can overcome the drawbacks of both SEC (unreliable calibra
tion) and MS (molecular weight distributions skewed to lower masses in
cases of polydisperse polymers). In addition, the flexibility of SEC/
ESI-MS using a tri-coaxial sheath-dow interface for post-column additi
on of cationization salt in appropriate solvents was briefly studied.