This document specifies a general method for determining the average molecular mass and mixture
ratio of poly(ethylene glycol) (PEG) and its derivatives with different end groups by matrix-assisted
laser desorption/ ionization time-of-flight mass spectrometry (MALDI-TOF-MS). It is applicable to PEG
and its derivatives with molecular masses from 500 g mol−1 to 20 000 g mol
−1. The composition is
calculated by means of a calibration curve constructed using standard polymer mixtures, where the
peak area ratio is plotted versus the mass ratio. This document can be applied to other polymers with
monomeric unit similar to PEG.