Abstract View
Prediction of Ion Mobility at High E/n Using the Two-Temperature Theory to Maximize Selectivity
VIRAJ GANDHI, Carlos Larriba-Andaluz, IUPUI
Abstract Number: 416
Working Group: Aerosol Physics
Abstract
The ability to separate ions in the gas phase using electrical mobility has become ubiquitous in the field of aerosol science. In particular, when coupled to a Mass Spectrometer (MS), a mobility analyzer can give information of mass over charge and shape of the molecules. One of the shortcomings of mobility is its low resolution which many times is insufficient to separate similar molecules. To overcome this problem, higher fields may be used to provide non-linear correlations that may allow to separate ions which would be otherwise non-separable at low fields. Here we use experimental results at high fields together with theory and numerical calculations to show that the mobility of non-spherical ions may be calculated quite accurately even at high fields. The two-temperature theory at the fourth order approximation is used to estimate the mobility from all-atom models showing errors of less than 3% with respect to experiments over the whole field range. This is the first time that these calculations have been attempted with this degree of accuracy. Moreover, by mixing different field strengths with different temperatures and gases, the mobility of an ion may be tailored. The effect of these parameters may be greatly enhanced by potential interactions, especially at low temperatures, making the method extremely unique and possibly a candidate for much higher mobility separation than exists at this time.