Variable low-mass filtering using an electrodynamic ion funnel.
An adjustable low-mass filter has been developed for an electrospray ionization (ESI) source to block ions associated with unwanted background species from entering the mass spectrometer. The low-mass filter is made by using an adjustable potential energy barrier from the conductance-limiting plate of an electrodynamic ion funnel, which prohibits species with higher ion mobilities from exiting the ESI source. We show that this arrangement provides a linear voltage adjustment for low-mass filtering from m/z 0 to 500. Mass filtering above m/z 500 is also performed; however, higher-mass species are attenuated. The mass filter was tested with a liquid chromatography/mass spectrometry (LC/MS) analysis of a bovine serum albumin (BSA) tryptic digest and resulted in the ability to block low-mass, background species, which accounted for 40-70% of the total ion current immediately behind the ESI source during peak elution and detection.
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Jason S
JS
Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99354, USA.
Tolmachev
Aleksey V
AV
Tang
Keqi
K
Smith
Richard D
RD
D000818:Animals; D002417:Cattle; D002853:Chromatography, Liquid / Q000379:methods; D010455:Peptides / Q000032:analysis; D012710:Serum Albumin, Bovine / Q000737:chemistry* / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D014357:Trypsin / Q000378:metabolism
D010455:Peptides; D012710:Serum Albumin, Bovine; D014357:Trypsin