POLYMER ANALYSIS BY MICROSCALE SIZE-EXCLUSION CHROMATOGRAPHY MALDI TIME-OF-FLIGHT MASS-SPECTROMETRY WITH A ROBOTIC INTERFACE

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.