Determination of linear response in the detection of mixtures of aroma compounds by atmospheric pressure ionization-mass spectrometry (API-MS)

The linearity of atmospheric pressure ionization-mass spectrometry (API-MS) response in mixtures of aroma compounds was determined for a 'homogeneous' system (four esters) and a 'heterogeneous' system (five compounds of different chemical functionality). All combinations analysed within each system followed a saturation pattern as concentration increased. Total linear responses were determined by the linear behaviour of individual compounds. Ionization patterns within each mixture were explained by proton affinity data (i.e. the species' ability to accept protons), molecular reaction rates (defined by molecular weight), and product ion distribution (according to fragmentation of the corresponding parent ion.)