Differential Ion Mobility Separations in the Low-Pressure Regime.
Anal Chem
; 90(1): 936-943, 2018 01 02.
Article
em En
| MEDLINE
| ID: mdl-29179535
ABSTRACT
Ion mobility spectrometry (IMS) in conjunction with mass spectrometry (MS) has emerged as a powerful platform for biological and environmental analyses. An inherent advantage of differential or field asymmetric waveform IMS (FAIMS) based on the derivative of mobility vs electric field over linear IMS based on absolute mobility is much greater orthogonality to MS. Effective coupling of linear IMS to MS and diverse IMS/MS arrangements and modalities impossible at ambient buffer gas pressure were enabled at much reduced pressures. In contrast, FAIMS devices operate at or near atmospheric pressure, which complicated integration with MS. Here, we show FAIMS at â¼15-30 Torr using a planar-gap stage within the MS instrument envelope. Fields up to â¼300 Td permitted by the Paschen law at these pressures greatly raise the separation speed, providing fair resolution in â¼10 ms and FAIMS scans in under 5 s. Rapid separation and efficient ion collection at low pressure minimize losses in the FAIMS step. Separations for key analyte classes and their dependences on electric field mirror those at ambient pressure. The potential for proteomics is demonstrated by separations of isomeric peptides with variant localization of post-translational modifications.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Anal Chem
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Estados Unidos