Selective ion storage, SIS

The selected ion recording (SIR) mode consists of recording only one or a few selected ions characteristic of the analytes studied. Selected ion monitoring (SIM) and selected ion storage (SIS) are more specific terms commonly employed by quadrupole and ion trap users, respectively. 

El selective ion storage range mlz 170-260 SIS mlz 300 for Cl experiments MS/MS experiments in waveform resonant mode, parent ion mlz 299... 

ITMS conditions Prescan ionization time 1500 ps (El) and lOOps (Cl) El Selective ion storage range m/z 170-260 SIS m/z 300 for Cl MS/MS in waveform resonant mode, parent ion m/z 299... 

The use of SIM analysis with ion trap mass spectrometers has also been developed. Through special control of the analyser (waveform ion isolation) during the ionization phase only the preselected ions of analytical interest are stored (SIS, selective ion storage). This technique allows the detection of selected ions in ion storage mass spectrometers in spite of the presence of complex matrices or the coelution of another component in high concentration. As the storage capacity of the ion trap analyser is only used for a few ions instead of for a full spectrum, very low detection limits are possible (<1 pg/component) and the usable dynamic range of... 

Ion storage technique for the ion trap analyser. By using resonance frequencies the ion trap can exclude ions of several miz values from storage (e.g. from the matrix) and collect selectively determined pre-selected analyte ions, also SIS. 

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