A Study of Silicon-Based Materials as Matrices for Matrix-Assisted Laser Desorption/lonization Time-of-Flight Mass Spectrometry

Abstract

<p> This thesis provides examples ~f new solid supports for Matrix-Assisted Laser Desorption Ionization Time-of-Flight (MALDI-TOF) in two parts. </p> <p> Firstly, mesoporous and macroporous silicas were developed as new supports for the elimination of low mass interference signals in the mass spectrum. Due to the complexity of the system, a variety of factors were studied, such as sol gel morphology, matrix crystallization, polymeric molecular weight and concentration. It was observed that the mesoporous silicas and higher matrix crystallization were advantageous for optimal signal intensity and signal-to-background ratio. </p> <p> Secondly, due to the inconsistencies in the literature apropos the role of the matrix in MALDI process, we have developed chemically modified compounds and studied these as alternative MALDI matrices. It was concluded that for optimal free matrix performance, the phenolic groups were desirable while crystallization was not required. Moreover, a highly selective covalently linked silicon-based matrix was developed, which yielded a superior signal-to-background ratio at moderate signal intensities. A chemical nature of matrix and sol gel processing methodology used were the relevant factors to be considered when optimizing a tethered matrix. It was demonstrated that requirements for free and surface-bound matrices were different; hence, suggesting the drastic difference in their operating mechanisms during MALDI process. </p>