Analysis of mixtures of organic volatile compound in water by MIMS. Semiquantitative evaluation of data

Chemometric analysis of intensities of ion currents measured by MIMS was demonstrated on two mixtures: nonpolar mixture containing benzene–toluene– p -xylene (set I) and polar mixture containing methanol–ethanol–propan-1-ol (set II), both in water solutions. The acquired MIMS data were evaluated off-line using Solver, a tool of Microsoft Excel and then verified by calculation of relative concentrations of components in mixtures. For evaluation we considered the additivity of ion currents coming from fragmentation of components, independent vapor permeation of components through membrane and unimolecular conditions in ion source of MS. By using this evaluation analysis it is possible to determine relative concentrations of organic substances in mixture, which penetrated through the membrane, without any separation. Set I penetrated according to the model analysis and the obtained relative concentrations were in reasonable agreement with the preset values. On the contrary, for set II the agreement of adjusted and calculated relative concentrations was not achieved due to high dielectric permittivity of alcohols.