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

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 (c) 2018 The Institute of Brewing & Distilling