in lucky survivor model, positive ions can formed highly charged clusters produced during break-up of matrix- , analyte-containing solid.
the lucky survivor model (cluster ionization mechanism) postulates analyte molecules incorporated in matrix maintaining charge state solution. ion formation occurs through charge separation upon fragmentation of laser ablated clusters. ions not neutralized recombination photoelectrons or counter ions so-called lucky survivors.
the thermal model postulates high temperature facilitates proton transfer between matrix , analyte in melted matrix liquid. ion-to-neutral ratio important parameter justify theoretical model, , mistaken citation of ion-to-neutral ratio result in erroneous determination of ionization mechanism. model quantitatively predicts increase in total ion intensity function of concentration , proton affinity of analytes, , ion-to-neutral ratio function of laser fluences. model suggests metal ion adducts (e.g., [m+na] or [m+k]) generated thermally induced dissolution of salt.
the matrix-assisted ionization (mai) method uses matrix preparation similar maldi not require laser ablation produce analyte ions of volatile or nonvolatile compounds. exposing matrix analyte vacuum of mass spectrometer creates ions identical charge states electrospray ionization. suggested there mechanistic commonality between process , maldi.
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