Quantification of Carbohydrates and Related Materials Using Sodium Ion Adducts Produced by Matrix-Assisted Laser Desorption Ionization.

The utility of sodium ion adducts produced by matrix-assisted laser desorption ionization for the quantification of analytes with multiple oxygen atoms was evaluated. Uses of homogeneous solid samples and temperature control allowed the acquisition of reproducible spectra. The method resulted in a direct proportionality between the ion abundance ratio I([A + Na])/I([M + Na]) and the analyte concentration, which could be used as a calibration curve.

Quantitative transfer of polar analytes on a solid surface to a liquid matrix in MALDI profiling.

In profiling of a specimen by matrix-assisted laser desorption ionization (MALDI) using a solid matrix, the solvent of the matrix solution extracts an analyte(s). A quantitative profiling cannot be achieved if the solvent evaporates before the complete extraction of the analyte. The extraction can become more quantitative when a liquid matrix dissolved in a solvent is used, which remains a liquid even after the evaporation of the solvent.

Discovery of a solvent effect preventing quantitative profiling by matrix-assisted laser desorption/ionization and its treatment.

Rationale: In analyte profiling by matrix-assisted laser desorption/ionization (MALDI), drawing a quantitative profile map is an outstanding problem. Recently, we developed a method to quantify an analyte by MALDI, which is needed to solve the problem. Another requirement for quantitative profiling is the quantitative sample-to-matrix analyte transfer, which is investigated in this work.

Investigations of Some Liquid Matrixes for Analyte Quantification by MALDI.

Sample inhomogeneity is one of the obstacles preventing the generation of reproducible mass spectra by MALDI and to their use for the purpose of analyte quantification. As a potential solution to this problem, we investigated MALDI with some liquid matrixes prepared by nonstoichiometric mixing of acids and bases. Out of 27 combinations of acids and bases, liquid matrixes could be produced from seven.