title: Use of a programmed temperature vaporizer and an in situ derivatization reaction to improve sensitivity in headspace-gas chromatography. Application to the analysis of chlorophenols in water.
abstract: In the present work we propose the combined use of a derivatization reaction within the vial of a headspace sampler with a programmed temperature vaporizer (PTV) inlet in the solvent vent mode as a new methodology for obtaining an increase in sensitivity in headspace-gas chromatography (HS-GC) for the analysis of sparingly volatile compounds. As test analytes the following chlorophenols were used: 2-chlorophenol (2CP), 2,4-dichlorophenol (24DCP), 4-chloro-3-methylphenol (4C3MP) and 2,4,6-trichlorophenol (246TCP). The derivatization reaction was carried out with acetic anhydride because it can be carried out in situ in aqueous medium. In the programmed temperature vaporizer inlet, three different liners, one of them empty and the others with materials of different trapping strengths (glass wool and Tenax-TA), were compared. The best results were obtained when an empty liner was used, with better repeatability and S/N ratios. In the case of the liner filled with Tenax-TA, a considerable lack of repeatability was observed, this being attributed to interactions between the derivatized compounds and the adsorbent. The proposed methodology affords very low limits of detection, in the range of a few ng/L for all the compounds, with good precision and accuracy values.
authors.affiliation: Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Ciencias Químicas, Universidad de Salamanca, 37008 Salamanca, Spain. jlpp@usal.es
authors.forename: José Luis
authors.initials: JL
authors.lastname: Pérez Pavón
authors.forename: Ana María
authors.initials: AM
authors.lastname: Casas Ferreira
authors.forename: María Esther
authors.initials: ME
authors.lastname: Fernández Laespada
authors.forename: Bernardo
authors.initials: B
authors.lastname: Moreno Cordero
mesh_terms: D000704:Analysis of Variance; D002733:Chlorophenols / Q000032:analysis*; D002849:Chromatography, Gas / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013696:Temperature; D055549:Volatile Organic Compounds / Q000032:analysis*; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply / Q000032:analysis
chemical_list: D002733:Chlorophenols; D055549:Volatile Organic Compounds; D014874:Water Pollutants, Chemical; D014867:Water