Application of response surface design to optimise the chromatographic analysis of volatile compounds in beer

Abstract

Solid-phase microextraction (SPME) combined with gas chromatography and mass spectrometry (GC–MS) is a rapid method for the analysis of different aromatic compounds in beer. However, chromatographic systems are affected by different parameters and optimization is time-consuming process, but essential for establishing optimal conditions for the quantification of analytes. An automated system consisting of headspace (HS)–SPME extraction combined with GC–MS was optimized for the determination of 19 volatile compounds responsible for important flavours and off-flavours of beer. The optimisation process consisted of two steps: the SPME fibre type was chosen, and subsequently four extraction parameters (temperature, time, sodium chloride concentration and pH) were optimised by a central composite design model. After optimisation, standard compounds were validated with relative standard deviations not exceeding 15%rel. The square of correlation coefficient for the calibration curves was ≥0.9559, indicating a linear response and the suitability of these HS-SPME conditions. Copyright © 2018 The Institute of Brewing & Distilling