Detection of High Molecular Weight Narrow Polydisperse Polymers up to 1.5 Million Daltons by MALDI Mass Spectrometry.

The detection of very high molecular weight narrow polydisperse poly(styrene) samples by MALDI time-of-flight mass spectrometry is reported. It is shown that accurate molecular weight determinations of samples up to 1 million can be achieved very rapidly from the singly charged polymeric species. For a poly(styrene) with a molecular weight of approximately 1.5 million, signals corresponding to the multiply charged ions of the principal distribution are observed. The molecular weights obtained by MALDI are in good agreement with classical molecular weight determination techniques. all-trans-Retinoic acid was used as the organic matrix for the laser desorption procedure, and the samples were analyzed as their silver cation adducts. This work demonstrates that, with proper matrix selection and sample preparation, MALDI can be a very useful tool for high molecular weight polymer sample analysis.