Fundamentals of Fragmentation Matrix Assisted Laser Desorption/Ionization Mass Spectrometry

Abstract

In 1981 Barber and Liu and coworkers [1,2] independently introduced the concept of employing matrix-assisted desorption/ionization where the absorption of the matrix is chosen to coincide with the wavelength of the employed laser to assist in the volatilization of materials. In 1988 Tanaka, Hillenkamp and coworkers [3,4] employed the laser as the energy source giving birth to matrix-assisted laser/ desorption mass spectroscopy (MALDI MS). MALDI MS was developed for the analysis of nonvolative samples and was heralded as an exciting new MS technique for the identification of materials with special use in the identification of polymers. It has fulfilled this promise to only a limited extent. Whereas it has become a well-used and essential tool for biochemists in exploring mainly nucleic acids and proteins, it has been only sparsely employed by synthetic polymer chemists. Why has MALDI MS been largely neglected by most synthetic polymer chemists? The answer involves the lack of congruency between the requirements of MALDI MS and most synthetic polymers. This chapter describes a new approach that allows MALDI MS to be of greater use to the analysis of synthetic polymers and investigates why it has not been useful in the past to the analysis of such polymers. We have employed various forms of MALDI MS for about 5 years and have developed a technique that will be described here. We have previously reported some of our results in journals and national meetings but have not previously given the foundational data that allows this technique to be viable.