Confirms metabolites by correlation comparison to parent drug
Performs fully automated data acquisition and processing in batch mode
Includes a powerful library search function
Contains an easy-to-use browser for viewing results
The result is a unique LC/MS/MS platform that can identify more metabolites in less time, and quantitate them too. In this study, the Q TRAP system was used to identify Phase I and Phase II metabolites of buspirone.
The Q TRAP system has the advantage of using highly selective scan functions such as neutral loss and precursor ion scans to facilitate detection of important biotransformation products from complex matrices. The structure and mass spectrum of buspirone (Figure 1) lead to the prediction that fragmentation that can occur on the A or B side of the structure can be identified using precursor ion scans at mass 122 and 168, respectively. Further information can be gained by using these two masses in combination with masses of expected transformations, i.e. precursor ion of 138 for hydroxylation occurring on the A side.
Figure 2 compares a normal full scan TIC trace from a liquid chromatography gradient run to a precursor ion scan of mass 122 and demonstrates the gain in selectivity. Up to two precursor ion scans can be combined in the Information Dependent Acquisition (IDA) survey step, minimizing the number of injections required to gain maximum information.
Figure 3 shows XIC traces of two metabolites that were identified with a precursor ion scan of mass 122 plus buspirone. An enhanced product ion (EPI) scan of a peak at 6.86 minutes from the XIC 402 trace confirms hydroxy-buspirone as a major metabolite and provides important information on the site of modification. The IDA method also contained an enhanced resolution scan that improv