Tandem MS on QqLIT Instruments

The QqLIT design basically presents a triple quadrupole instrumeait having Q3 exchanged for a linear ion trap. As such, it offers all scan modes and properties typical for QqQ instruments (Chap. 9.7) plus those additional ones that are enabled by the LIT, i.e., higher-order tandem MS and combinations of ion accumulation and subsequent scanning for enhanced sensitivity (Fig. 9.23) [115,118-120]. 

Example The fragmentation pathways of ions of Trocade , an anti-rheumatoid drug, [trocade+H] , m/z 437, were elucidated by sequential tandem MS up to MS on a QqLIT instrument (Fig. 9.24). The protonated molecule first eliminates hydroxylamine, 33 u, to yield the acylium ion fragment at m/z 404, which in turn cleaves off the imidazolidinedione substituent at the a-carbon prior to loss of CO from the fragment ion at m/z 262 [115]. 

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