title: Differential mobility spectrometry with nanospray ion source as a compact detector for small organics and inorganics.
abstract: Electrospray ionization (ESI) is an important tool in chemical and biochemical survey and targeted analysis in many applications. For chemical detection and identification electrospray is usually used with mass spectrometry (MS). However, for screening and monitoring of chemicals of interest in light, low power field-deployable instrumentation, an alternative detection technology with chemical selectivity would be highly useful, especially since small, lightweight, chip-based gas and liquid chromatographic technologies are being developed. Our initial list of applications requiring portable instruments includes chemical surveys on Mars, medical diagnostics based on metabolites in biological samples, and water quality analysis. In this report, we evaluate ESI-Differential Mobility Spectrometry (DMS) as a compact, low-power alternative to MS detection. Use of DMS for chemically-selective detection of ESI suffers in comparison with mass spectrometry because portable MS peak capacity is greater than that of DMS by 10X or more, but the development of light, fast chip chromatography offers compensating resolution. Standalone DMS provides the chemical selectivity familiar from DMS-MS publications, and exploits the sensitivity of ion detection. We find that sub-microliter-per-minute flows and a correctly-designed interface prepare a desolvated ion stream that enables DMS to act as an effective ion filter. Results for a several small organic biomarkers and metabolites, including citric acid, azelaic acid, n-hexanoylglycine, thymidine, and caffeine, as well as compounds such as dinitrotoluene and others, have been characterized and demonstrate selective detection. Water-quality-related halogen-containing anions, fluoride through bromate, contained in liquid samples are also isolated by DMS. A reaction-chamber interface is highlighted as most practical for portable ESI-DMS instrumentation.
authors.affiliation: Planetary Chemistry and Astrobiology, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109-8099.
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Coy
authors.forename: Evgeny V
authors.initials: EV
authors.lastname: Krylov
authors.forename: Erkinjon G
authors.initials: EG
authors.lastname: Nazarov
authors.forename: Albert J
authors.initials: AJ
authors.lastname: Fornace
authors.forename: Richard D
authors.initials: RD
authors.lastname: Kidd
keywords: DMS; FAIMS; differential ion mobility; electrospray; ion mobility; nanospray
references.citation: Rev Sci Instrum. 2010 Feb;81(2):024101
references.pmid: 20192506
references.citation: Anal Chem. 2006 Nov 15;78(22):7697-706
references.pmid: 17105161
references.citation: Annu Rev Anal Chem (Palo Alto Calif). 2009;2:187-214
references.pmid: 20636059
references.citation: J Am Soc Mass Spectrom. 2010 Sep;21(9):1477-81
references.pmid: 20619673
references.citation: Anal Chem. 2006 Dec 15;78(24):8200-6
references.pmid: 17165808
references.citation: Analyst. 2008 Aug;133(8):1064-71
references.pmid: 18645648
references.citation: Int J Mass Spectrom. 2010 Dec 1;298(1-3):45-54
references.pmid: 21278836
references.citation: Anal Chem. 2010 Mar 1;82(5):1867-80
references.pmid: 20121077
references.citation: Eur J Mass Spectrom (Chichester). 2010;16(1):57-71
references.pmid: 20065515
references.citation: Mass Spectrom Rev. 2009 Nov-Dec;28(6):870-97
references.pmid: 19626583
references.citation: Anal Chem. 2008 Aug 1;80(15):5873-83
references.pmid: 18582088
references.citation: Mass Spectrom Rev. 2013 Jan-Feb;32(1):43-71
references.pmid: 22941854
references.citation: Int J Ion Mobil Spectrom. 2012 Sep 1;15(3):
references.pmid: 24311968
references.citation: J Am Soc Mass Spectrom. 2010 Feb;21(2):209-14
references.pmid: 19892569
references.citation: JALA Charlottesv Va. 2010 Dec;15(6):433-439
references.pmid: 21278840
references.citation: Rapid Commun Mass Spectrom. 2013 Jul 15;27(13):1473-80
references.pmid: 23722681
references.citation: Anal Chem. 2008 Mar 1;80(5):1800-5
references.pmid: 18237189
references.citation: Anal Chem. 2006 Jan 1;78(1):96-106
references.pmid: 16383315
references.citation: J Am Soc Mass Spectrom. 2013 Sep;24(9):1428-36
references.pmid: 23797861
references.citation: J Am Soc Mass Spectrom. 2007 Mar;18(3):502-11
references.pmid: 17141523
references.citation: Anal Chem. 2006 Jun 1;78(11):3706-14
references.pmid: 16737227
references.citation: Anal Chem. 2007 Dec 15;79(24):9302-9
references.pmid: 17997523
references.citation: Bioanalysis. 2012 Jun;4(11):1363-75
references.pmid: 22720654
references.citation: Int J Radiat Biol. 2011 Aug;87(8):802-23
references.pmid: 21692691
references.citation: Anal Chem. 2008 Oct 1;80(19):7198-205
references.pmid: 18754674
references.citation: Int J Mass Spectrom. 2010 Apr 15;291(3):108-117
references.pmid: 20305793
references.citation: J Mass Spectrom. 2008 Jan;43(1):1-22
references.pmid: 18200615
references.citation: Radiat Res. 2008 Jul;170(1):1-14
references.pmid: 18582157