KCS

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a fast and versatile technique to obtain the molar mass of a compound, where a laser light is irradiated on the sample target which is normally composed of an analyte and an organic matrix. Due to its ease of operation, fast analysis times, high mass accuracy, and high mass resolution, MALDI-MS is commonly used for rapid analyses of proteins, peptides, synthetic polymers, carbohydrates, and other macromolecules. There are two major drawbacks in MALDI-MS analyses. First, there is almost always interference in the low m/z region, e.g., < m/z 500, due to matrix fragments or its cluster peaks from common matrices. The second drawback is the possibility of inhomogeneity in the distribution of matrix within a MALDI spot. This often leads to poor reproducibility and poor quantitative results. Various efforts have been tried to overcome these drawbacks.
During the presentation, various efforts to improve the performance of MALDI-MS for the analysis of proteins, carbohydrates, lipids, or explosives will be presented. Different matrix materials, additive cations, and additive acids have been tried to analyze small molecules or improve the sensitivity of MALDI-MS. Charcoal could be used as an alternative matrix for the analysis of small molecules. Phosphoric acid was found to be an effective additive for the analysis of peptides with 2,5-dihydroxybenzoic acid matrix. MALDI-MS sample preparation using free-vacuum drying where the matrix-analyte mixture is first frozen and then dried under vacuum, resulted in a homogeneously crystallized matrix-analyte mixture appropriate for quantitative MALDI-MS analysis, improving the reproducibility of MALDI-MS analysis.