Method development by GC-ECD and HS-SPME-GC-MS for beer volatile analysis.

Two methods for the extraction, identification and quantification of the highest occurrence and lowest perception threshold off-flavours in fifteen different samples of Brazilian Pilsner beers were developed. For this purpose, headspace solid phase microextraction in combination with a gas chromatography coupled to a mass spectrometric detection (HS-SPME-GC-MS) as well as headspace extraction in combination with a gas chromatography coupled to electron capture detection (HS-GC-ECD) were evaluated. The first and the second methods were used for esters and vicinal diketones analysis, respectively. All data were comprehended below the taster's threshold detection limit: ethyl acetate 39.48 ng mL(-1) (RSD mean value 4.2%), isoamyl acetate 3.88 ng mL(-1) (RSD mean value 3.4%), ethyl hexanoate 0.61 ng mL(-1) (RSD mean value 3.1%) and 2,3-butanedione 0.10 ng mL(-1) (RSD mean value 2.9%). The validated method demonstrated to be useful for the analysis of highest incidence beer off-flavours.