Methods and systems for performing ion mobility spectrometry are provided herein. In accordance with various aspects of the applicant's teachings, the methods and systems can provide for the separation of biologically relevant acids that may be difficult to separate with conventional MS techniques. In various aspects, methods and systems in accordance with applicant's teachings can enable a differential mobility spectrometer to resolve biologically relevant acids through the use of CO2 as the drift gas in combination with Acetone.
