title: Limits of detection for the determination of mono- and dicarboxylic acids using gas and liquid chromatographic methods coupled with mass spectrometry.
abstract: The chromatographic separation and instrumental limits of detection (LODs) were obtained for a broad range of C(1)-C(18) monocarboxylic (MCAs) and C(2)-C(14) dicarboxylic acids (DCAs) employing either chemical derivatization followed by gas chromatography-mass spectrometry and flame ionization detection (GC-MS/FID) or direct analysis with liquid chromatography high resolution MS and tandem MS (LC-MS). Suitability, efficiency and stability of reaction products for several derivatization agents used for esterification (BF(3)/butanol), and trimethysilylation, including trimethylsilyl-N-N-dimethylcarbamate (TMSDMC) and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) were evaluated. The lowest limits of detection for the majority of compounds below 10 pg (with the exception of acetic acid) were obtained for derivatization with BF(3)/butanol followed by GC-MS in the total ion current (TIC) mode. Further improvements were achieved when applying either selected ion monitoring (SIM), which decreased the LODs to 1-4 pg or a combination of SIM and TIC (SITI) (2-5 pg). GC-FID provided LODs comparable to those obtained by GC-MS TIC. Both trimethylsilylation (followed by GC-MS) and direct LC-MS/MS analysis yielded LODs of 5-40 pg for most of the acids. For volatile acids the LODs were higher, e.g., 25 and 590 ng for TMSDMC and BSTFA derivatized formic acid, respectively, whereas the LC-MS methods did not allow for the analysis of formic acid at all.
authors.affiliation: University of North Dakota, Department of Chemistry, 151 Cornell Street Stop 9024, Grand Forks, ND 58202, USA.
authors.forename: Jana
authors.initials: J
authors.lastname: Šťávová
authors.forename: Josef
authors.initials: J
authors.lastname: Beránek
authors.forename: Eric P
authors.initials: EP
authors.lastname: Nelson
authors.forename: Bonnie A
authors.initials: BA
authors.lastname: Diep
authors.forename: Alena
authors.initials: A
authors.lastname: Kubátová
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods; D003998:Dicarboxylic Acids / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D007202:Indicators and Reagents / Q000737:chemistry; D057230:Limit of Detection; D013058:Mass Spectrometry / Q000379:methods*; D014297:Trimethylsilyl Compounds / Q000737:chemistry
chemical_list: D003998:Dicarboxylic Acids; D007202:Indicators and Reagents; D014297:Trimethylsilyl Compounds; C047270:N,N-bis(trimethylsilyl)-2,2,2-trifluoroacetamide