Rapid detection and identification of impurities in ten 2-naphthalenamines using an atmospheric pressure solids analysis probe in conjunction with ion mobility mass spectrometry.

The atmospheric pressure solids analysis probe (ASAP), in conjunction with ion mobility time-of-flight mass spectrometry (IM-ToF-MS), has been applied to the impurity profiling study of ten 2-naphthalenamines. The impurity profiles achieved by ASAP-IM-MS were compared with those obtained by liquid chromatography-electrospray ionisation-mass spectrometry (LC-ESI-MS). All the impurities at the level of 0.1 area % and above, except for one, detected by LC-ESI-MS, were also found by ASAP-IMS analyses. In addition, one non-polar compound was detected by ASAP-IM-MS alone. The IM-MS plot of ion drift time versus m/z values offered sufficient separation between the impurities with different m/z. Therefore, instead of LC as a separation tool, IM-MS is able to provide fingerprint profiling for the ten samples analysed. The time of each analysis has been reduced from 25 min by LC-MS to less than 3 min by ASAP-IM-MS. When collision energy was applied for the selected precursor ion in the transfer T-wave, a clean MS/MS spectrum was obtained for structural elucidation of unknown impurities. The hyphenation of ASAP and IM-MS techniques represents a highly efficient approach for rapid detection and identification of impurities generated in complex reactions involved in pharmaceutical development.