ELECTROSPRAY-IONIZATION MASS-SPECTROMETRY OF POLY(STYRENE)

The effect of cone voltage on the polymer mass distribution of non-pol ar poly(styrene) samples has been investigated using electrospray ioni zation. It was found that relatively high cone voltages (120 V) were r equired to ionize non-polar polymers. At lower cone voltages (30-60 V) , cluster ions, e.g. [M+2cat](2+) and [2M+cat](4), were observed. Sing ly-charged species predominated only at high cone voltages, but no fra gmentation of the oligomer ions has been seen. The molecular mass dist ributions obtained by electrospray ionization have been compared with those obtained by size-exclusion chromatography and the agreement (gen erally within 10%) has been shown to be cone-voltage dependent.