title: Charge enhancement of single-stranded DNA in negative electrospray ionization using the supercharging reagent meta-nitrobenzyl alcohol.
abstract: Charge enhancement of single-stranded oligonucleotide ions in negative ESI mode is investigated. The employed reagent, meta-nitrobenzyl alcohol (m-NBA), was found to improve total signal intensity (Itot), increase the highest observed charge states (zhigh), and raise the average charge states (zavg) of all tested oligonucleotides analyzed in negative ESI. To quantify these increases, signal enhancement ratios (SER1%) and charge enhancement coefficients (CEC1%) were introduced. The SER1%, (defined as the quotient of total oligonucleotide ion abundances with 1% m-NBA divided by total oligonucleotide abundance without m-NBA) was found to be greater than unity for every oligonucleotide tested. The CEC1% values (defined as the average charge state in the presence of 1% m-NBA minus the average charge state in the absence of m-NBA) were found to be uniformly positive. Upon close inspection, the degree of charge enhancement for longer oligonucleotides was found to be dependent upon thymine density (i.e., the number and the location of phospho-thymidine units). A correlation between the charge enhancement induced by the presence of m-NBA and the apparent gas-phase acidity (largely determined by the sequence of thymine units but also by the presence of protons on other nucleobases) of multiply deprotonated oligonucleotide species, was thus established. Ammonium cations appeared to be directly involved in the m-NBA supercharging mechanism, and their role seems to be consistent with previously postulated ESI mechanisms describing desorption/ionization of single-stranded DNA into the gas phase.
authors.affiliation: Institut Parisien de Chimie Moléculaire, Equipe de Chimie Structurale Organique et Biologique, Université Pierre et Marie Curie, CNRS UMR 7201, 75252, Paris cedex 05, France.
authors.forename: Bessem
authors.initials: B
authors.lastname: Brahim
authors.forename: Sandra
authors.initials: S
authors.lastname: Alves
authors.forename: Richard B
authors.initials: RB
authors.lastname: Cole
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Tabet
mesh_terms: D001483:Base Sequence; D001592:Benzyl Alcohols / Q000737:chemistry*; D004277:DNA, Single-Stranded / Q000737:chemistry*; D005740:Gases / Q000737:chemistry; D007202:Indicators and Reagents / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D001592:Benzyl Alcohols; D004277:DNA, Single-Stranded; D005740:Gases; D007202:Indicators and Reagents; C046886:3-nitrobenzyl alcohol
references.citation: J Am Soc Mass Spectrom. 1992 Feb;3(2):113-21
references.pmid: 24242879
references.citation: Anal Chem. 2005 May 1;77(9):2992-6
references.pmid: 15859621
references.citation: Anal Chem. 2001 Apr 1;73(7):1455-60
references.pmid: 11321294
references.citation: J Phys Chem A. 2006 Mar 23;110(11):3992-4000
references.pmid: 16539422
references.citation: Phys Chem Chem Phys. 2010 Nov 7;12(41):13476-83
references.pmid: 20877871
references.citation: Chem Rev. 2005 May;105(5):1869-915
references.pmid: 15884792
references.citation: Anal Chem. 2010 Nov 1;82(21):9050-7
references.pmid: 20942406
references.citation: Anal Chem. 1991 Sep 15;63(18):1971-8
references.pmid: 1661106
references.citation: J Am Soc Mass Spectrom. 1999 Nov;10(11):1095-104
references.pmid: 10536816
references.citation: Phys Chem Chem Phys. 2011 Nov 7;13(41):18288-96
references.pmid: 21399817
references.citation: J Am Soc Mass Spectrom. 2012 Mar;23(3):489-97
references.pmid: 22219044
references.citation: Curr Opin Biotechnol. 1998 Feb;9(1):25-34
references.pmid: 9503584
references.citation: J Am Chem Soc. 2003 Feb 26;125(8):2319-27
references.pmid: 12590562
references.citation: Anal Chem. 2003 Sep 1;75(17):4525-33
references.pmid: 14632060
references.citation: J Am Soc Mass Spectrom. 2009 Oct;20(10):1933-43
references.pmid: 19682923
references.citation: J Mass Spectrom. 2000 Jul;35(7):804-17
references.pmid: 10934434
references.citation: J Am Soc Mass Spectrom. 2010 Jan;21(1):127-31
references.pmid: 19854660
references.citation: J Am Soc Mass Spectrom. 2005 Jul;16(7):1060-6
references.pmid: 15914017
references.citation: J Mass Spectrom. 2007 Dec;42(12):1613-22
references.pmid: 18085569
references.citation: Anal Chem. 2010 Sep 1;82(17):7422-9
references.pmid: 20712348
references.citation: J Am Soc Mass Spectrom. 2010 Jul;21(7):1144-50
references.pmid: 20356762
references.citation: J Am Soc Mass Spectrom. 2010 Oct;21(10):1762-74
references.pmid: 20673639
references.citation: J Am Soc Mass Spectrom. 2003 Jan;14(1):23-41
references.pmid: 12504331
references.citation: Curr Opin Biotechnol. 1995 Feb;6(1):96-102
references.pmid: 7534508
references.citation: J Am Soc Mass Spectrom. 2004 Apr;15(4):510-22
references.pmid: 15047056
references.citation: J Am Soc Mass Spectrom. 2009 Apr;20(4):593-6
references.pmid: 19101165
references.citation: Anal Chem. 2012 Jun 5;84(11):4647-51
references.pmid: 22571167
references.citation: J Am Soc Mass Spectrom. 2003 Feb;14(2):161-70
references.pmid: 12586465
references.citation: J Am Soc Mass Spectrom. 2008 Jul;19(7):938-46
references.pmid: 18467119
references.citation: Anal Chem. 2007 Dec 15;79(24):9243-52
references.pmid: 18020370
references.citation: J Mass Spectrom. 2009 Dec;44(12):1698-708
references.pmid: 19824038
references.citation: Int J Mass Spectrom. 2011 Mar 1;300(2-3):118-122
references.pmid: 21499519
references.citation: Science. 1989 Oct 6;246(4926):64-71
references.pmid: 2675315
references.citation: Anal Chem. 2003 Apr 1;75(7):1699-705
references.pmid: 12705605
references.citation: Mol Cell Proteomics. 2005 Dec;4(12):2010-21
references.pmid: 16249172
references.citation: J Mass Spectrom. 2005 Apr;40(4):430-43
references.pmid: 15838939
references.citation: Rapid Commun Mass Spectrom. 1996;10(1):144-9
references.pmid: 8563014
references.citation: Anal Chem. 2010 Sep 1;82(17):7515-9
references.pmid: 20704305
references.citation: Biopolymers. 2009 Jun;91(6):401-9
references.pmid: 19189378