AbstractThe application of solid phase microextraction (SPME) to gas chromatography–olfactometry (GC–O) dilution analysis has previously been achieved by varying the thickness of the fibre phase and the length of exposure. In this study, eight steps of dilution by a factor of 2 were achieved by splitting of the injected sample in different ratios in the gas chromatograph's injection port. Using solvent injection and SPME headspace sampling, it was found that the nominal split ratios of the hardware requires calibration to achieve the actual dilutions desired. This calibration method was applied to the CharmAnalysis of coffee as it was brewed. Copyright © 2004 John Wiley & Sons, Ltd.