Abstract: | Polyglycerol intermediates have been characterized by liquid chromatography-mass spectrometry (LC-MS) with electrospray ionization
(ESI). Linear and cyclic components from n=2–23 in a sample of decaglycerol, for example, have been resolved in the second dimension or mass axis. Molecular weight
(MW) distributions for tri-, hexa-, and decaglycerol products have been analyzed as a function of cone voltage and adduct
ion (H+, Li+, Na+, K+, Rb+, Cs+, and NH4
+). A different combination is required to obtain a reliable MW distribution for each polyglycerol intermediate. The best distribution
obtained by ESI/MS is determined by comparing the calculated hydroxyl number and cyclic content to that obtained by wet chemistry
and gas chromatography, respectively. Once ESI/MS conditions are established, the distribution can be used, for the first
time in polyglycerol analysis, to calculate important parameters such as number average MW, weight average MW, polydispersity,
% cyclics, hydroxyl number, wt% above n=6, etc. |