title: Qualitative and quantitative analysis of a group of volatile organic compounds in biological samples by HS-GC/FID: application in practical cases.
abstract: A simple and sensitive procedure, using n-propanol as internal standard (IS), was developed and validated for the qualitative and quantitative analysis of a group of 11 volatile organic substances with different physicochemical properties (1-butanol, 2-propanol, acetaldehyde, ethyl acetate, acetone, acetonitrile, chloroform, diethyl ether, methanol, toluene and p-xylene) in whole blood, urine and vitreous humor. Samples were prepared by dilution with an aqueous solution of internal standard followed by Headspace Gas Chromatography with a Flame-ionization Detector (HS GC-FID) analysis. Chromatographic separation was performed using two capillary columns with different polarities (DB-ALC2: 30m×0.320mm×1.2μm and DB-ALC1: 30m×0.320mm×1.8μm), thus providing a change in the retention and elution order of volatiles. This dual column confirmation increases the specificity, since the risk of another substance co-eluting at the same time in both columns is very small. The method was linear from 5 to 1000mg/L for toluene and p-xylene, 50-1000mg/L for chloroform, and 50-2000mg/L for the remaining substances, with correlation coefficients of over 0.99 for all compounds. The limits of detection (LOD) ranged 1 to 10mg/L, while the limits of quantification (LOQ) ranged from 2 to 31mg/L. The intra-day precision (CV<6.4%), intermediate precision (CV<7.0%) and accuracy (relative error ±10%) of the method were in conformity with the criteria normally accepted in bioanalytical method validation. The method developed has been applied to forensic cases, with the advantages that it uses a small sample volume and does not require any extraction procedure as it makes use of a headspace injection technique.
authors.affiliation: National Institute of Legal Medicine and Forensic Sciences-Centre Branch, Largo da Sé Nova, 3000-213 Coimbra, Portugal; CENCIFOR-Forensic Sciences Centre, Largo da Sé Nova, 3000-213 Coimbra, Portugal. Electronic address: carla.monteiro@dcinml.mj.pt.
authors.forename: C
authors.initials: C
authors.lastname: Monteiro
authors.affiliation: National Institute of Legal Medicine and Forensic Sciences-Centre Branch, Largo da Sé Nova, 3000-213 Coimbra, Portugal; CENCIFOR-Forensic Sciences Centre, Largo da Sé Nova, 3000-213 Coimbra, Portugal.
authors.forename: J M
authors.initials: JM
authors.lastname: Franco
authors.affiliation: National Institute of Legal Medicine and Forensic Sciences-Centre Branch, Largo da Sé Nova, 3000-213 Coimbra, Portugal; CENCIFOR-Forensic Sciences Centre, Largo da Sé Nova, 3000-213 Coimbra, Portugal.
authors.forename: P
authors.initials: P
authors.lastname: Proença
authors.affiliation: CENCIFOR-Forensic Sciences Centre, Largo da Sé Nova, 3000-213 Coimbra, Portugal; National Institute of Legal Medicine and Forensic Sciences-South Branch, Rua Manuel Bento de Sousa 3, 1150-219 Lisboa, Portugal.
authors.forename: A
authors.initials: A
authors.lastname: Castañera
authors.affiliation: National Institute of Legal Medicine and Forensic Sciences-Centre Branch, Largo da Sé Nova, 3000-213 Coimbra, Portugal.
authors.forename: A
authors.initials: A
authors.lastname: Claro
authors.affiliation: National Institute of Legal Medicine and Forensic Sciences-Centre Branch, Largo da Sé Nova, 3000-213 Coimbra, Portugal; CENCIFOR-Forensic Sciences Centre, Largo da Sé Nova, 3000-213 Coimbra, Portugal; Faculty of Medicine-University of Coimbra, Largo da Sé Nova, 3000-213 Coimbra, Portugal.
authors.forename: D N
authors.initials: DN
authors.lastname: Vieira
authors.affiliation: National Institute of Legal Medicine and Forensic Sciences-Centre Branch, Largo da Sé Nova, 3000-213 Coimbra, Portugal; CENCIFOR-Forensic Sciences Centre, Largo da Sé Nova, 3000-213 Coimbra, Portugal; Faculty of Medicine-University of Coimbra, Largo da Sé Nova, 3000-213 Coimbra, Portugal.
authors.forename: F
authors.initials: F
authors.lastname: Corte-Real
mesh_terms: D002849:Chromatography, Gas / Q000379:methods*; D005410:Flame Ionization; D006801:Humans; D057230:Limit of Detection; D014822:Vitreous Body / Q000737:chemistry; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D055549:Volatile Organic Compounds
keywords: Forensic toxicology; HS GC-FID; Validation; Volatile organic compound