Multiplexing ESI interface

TOF and Q-TOF instraments are freqnently applied in metabolism studies. The identity of the epothilone B metabolites fonnd by precnrsor-ion analysis (Figure 10.5, Ch. 10.4.2) was confirmed using accnrate-mass determination on a LC-TOF-MS instmment [29]. Some other examples are the characterization of metabolites of moclobemide and remikiren [32], the identification of ketobemidone Phase-I and Phase-II metabolites [33], and the identification of in vitro metabolites of ethoxidine [34]. The nse of a five-channel multiplexed ESI interface (four chaimels for parallel LC-MS and one channel for lock-mass componnd infusion) on a Q-TOF instrument was recently described to speed np metabolite identification and to enhance the efficient nse of the costly instrument [35]. 

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