TY - JOUR

T1 - A First Principle Model of Differential Ion Mobility

T2 - the Effect of Ion-Solvent Clustering

AU - Haack, Alexander

AU - Crouse, Jeff

AU - Schlüter, Femke Jutta

AU - Benter, Thorsten

AU - Hopkins, W. Scott

PY - 2019/12/1

Y1 - 2019/12/1

N2 - The use of differential mobility spectrometry (DMS) as a separation tool prior to mass analysis has increased in popularity over the years. However, the fundamental principles behind the difference between high- and low-field mobility is still a matter of debate—especially regarding the strong impact of solvent molecules added to the gas phase in chemically modified DMS environments. In this contribution, we aim to present a thorough model for the determination of the ion mobility over a wide range of field strengths and subsequent calculation of DMS dispersion plots. Our model relies on first principle calculations only, incorporating the modeling of the “hard-sphere” mobility, the change in CCS with field strength, and the degree of clustering of solvent molecules to the ion. We show that all three factors have to be taken into account to qualitatively predict dispersion plots. In particular, type A behavior (i.e., strong clustering) in DMS can only be explained by a significant change of the mean cluster size with field strengths. The fact that our model correctly predicts trends between differently strong binding solvents, as well as the solvent concentration and the background gas temperature, highlights the importance of clustering for differential mobility. [Figure not available: see fulltext.].

AB - The use of differential mobility spectrometry (DMS) as a separation tool prior to mass analysis has increased in popularity over the years. However, the fundamental principles behind the difference between high- and low-field mobility is still a matter of debate—especially regarding the strong impact of solvent molecules added to the gas phase in chemically modified DMS environments. In this contribution, we aim to present a thorough model for the determination of the ion mobility over a wide range of field strengths and subsequent calculation of DMS dispersion plots. Our model relies on first principle calculations only, incorporating the modeling of the “hard-sphere” mobility, the change in CCS with field strength, and the degree of clustering of solvent molecules to the ion. We show that all three factors have to be taken into account to qualitatively predict dispersion plots. In particular, type A behavior (i.e., strong clustering) in DMS can only be explained by a significant change of the mean cluster size with field strengths. The fact that our model correctly predicts trends between differently strong binding solvents, as well as the solvent concentration and the background gas temperature, highlights the importance of clustering for differential mobility. [Figure not available: see fulltext.].

KW - Collision cross section

KW - Dispersion plot

KW - DMS

KW - Ion mobility

KW - Population distribution

UR - http://www.scopus.com/inward/record.url?scp=85075337859&partnerID=8YFLogxK

U2 - 10.1007/s13361-019-02340-1

DO - 10.1007/s13361-019-02340-1

M3 - Article

C2 - 31755046

AN - SCOPUS:85075337859

VL - 30

SP - 2711

EP - 2725

JO - Journal of the American Society for Mass Spectrometry

JF - Journal of the American Society for Mass Spectrometry

SN - 1044-0305

IS - 12

ER -