Improvement of Low Mass Cutoff Effect Using Digital Ion Trap Technology / 分析化学

ABSTRACT

The low mass cutoff ( LMCO) is the main weakness of ion trap when it performs tandem mass analysis by collision induced dissociation (CID). LMCO means that some daughter ions of m/ z are less than about 1 / 3 of the m/ z of parent ion could not be detected during the tandem mass spectrometry processing. A new method which can significantly improve the effect of low mass cutoff was proposed and investigated. By simply changing the scan method of digital potential frequency, some low mass ions can be effectively observed during the tandem mass spectrometric experiment. In the experiment, the frequency of the digital ion trapping power and ion activation power were scanned from lower value to higher value, and some lower mass product ions could be detected during CID process. For example, some lower mass ions were observed during the CID of reserpine precursor ion when the frequency of its digital trapping power was scanned from 500 kHz to 560 kHz. The tandem mass spectra of Reserpine ion showed that the experimental results both from this work and the triple quadrupole mass spectrometer were exactly the same.