Separation of cisplatin and its hydrolysis products using electrospray ionization high-field asymmetric waveform ion mobility spectrometry coupled with ion trap mass spectrometry

Cisplatin and its mono- and dihydrated complexes have been separated using a high-field asymmetric waveform ion mobility spectrometry (FAIMS) analyzer interfaced with electrospray ionization (ESI) and ion trap mass spectrometry (ITMS). The addition of helium to the nitrogen curtain/carrier gas in the FAIMS device improved both the sensitivity and selectivity of the electrospray analysis. Introduction of a three-component mixture as curtain/carrier gas, nitrogen, helium, and carbon dioxide, resulted in further improvements to sensitivity. Compared with conventional ESI-MS, the background chemical noise in the ESI-FAIMS-ITMS spectrum was dramatically reduced, resulting in over 30-fold improvement in the signal-to-noise ratio for cisplatin. Analytical results were linear over the concentration range 10-200 ng/mL for intact cisplatin with a corresponding detection limit determined of 0.7 ng/mL with no derivatization or chromatographic separation prior to analysis.