The effect of tetrahydrofuran as solvent on matrix-assisted laser desorption/ionization and electrospray ionization mass spectra of functional polystyrenes.

It is demonstrated that tetrahydrofuran (THF) should be used with caution as a solvent in polymer sample preparation for matrix-assisted laser desorption/ionization (MALDI) analyses. The presence of peroxides in THF may cause the oxidation of chemically active groups. This effect is illustrated in the case of S-containing polystyrene derivatives. The oxidation of the trithiocarbonate group resulted in the formation of poly(styrene)sulfonic acids, R(CH(2)CHPh)(n)SO(3)H, which was detected in negative mode by MALDI and electrospray ionization (ESI) methods after the samples remained in THF for several hours.