Polydisperse synthetic polymers cannot be characterized reliably by ma
trix-assisted laser desorption/ionization time-of-night mass spectrome
try (MALDI MS) alone. Coupling of size-exclusion chromatography (SEC)
with MALDI MS provides both absolute mass calibration of the SEC colum
n based on the polymer itself and determination of monomers and end gr
oups from the mass spectra. Now a micro-scale SEC (mu SEC) system has
been developed in which the MALDI matrix solution is coaxially added t
o the column effluent and directly spotted onto the MALDI targets in a
robotic interface. Each spot corresponds with a 10-s elution window f
rom the mu SEC column, thus yielding a narrow polymer distribution whi
ch is amenable to characterization by MALDI MS. This mu SEC/MALDI MS s
ystem is less laborious and time-consuming and features very low solve
nt consumption and reduced solvent emission during the evaporation ste
p as compared to the conventional-sized SEC/fraction collector systems
applied in the past. The performance is demonstrated by the character
ization of a polybisphenol A carbonate and a complex dipropoxylated bi
sphenol A/adipic acid/isophthalic acid copolyester resin.