The Importance of Field Strength in the Low Field Portion of a Differential Ion Mobility Spectrometry Waveform (2015)

Undergraduates: Jesus Martinez-Alvarado, Brandon Santiago

Faculty Advisor: Gary Glish
Department: Chemistry

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Differential ion mobility spectrometry (DIMS) is a rapid separation technique that can be used to reduce chemical background in complex mixtures prior to analysis by mass spectrometry. DIMS separations use the dependence of ion mobility on electric field strength to separate ions. Through application of an asymmetric waveform alternating between ¿¿¿high¿¿¿ and ¿¿¿low¿¿¿ electric field strengths, the difference between high and low field mobilities is sampled. Ideally, this waveform would be rectangular in shape, but due to power requirements less ideal waveforms are typically used. One such waveform is a harmonics based waveform that capacitively couples two sinusoidal waveforms across the DIMS gap. Here we discuss the instrumental limitations of a two harmonic DIMS waveform in regards to its ability to truly sample between high and low electric fields.