Quantitative analysis of polypropyleneglycol mixtures by desorption/ionization on porous silicon mass spectrometry

Mixtures of diol and triol types of polypropyleneglycol (PPG) bearing two and three hydroxyl end groups were analyzed quantitatively by matrix-assisted laser desorption/ionization (MALDI) and desorption ionization on porous silicon (DIOS) with the conventional dried droplet method. The reproducibility of MALDI mass spectra depended on the factors regarding sample preparation such as the analyte/matrix ratio, and the type of solvent and/or chemical matrix employed. For DIOS, the analyte concentration and the selection of solvents were important for good reproducibility. Optimization of these factors allowed reliable quantification of the polymer mixtures. Under optimized conditions, DIOS would be suitable than MALDI for this purpose.