20 key coffee odorants were selected having a different volatility
and polarity. These were quantified in-cup by SPME–GC–MS using the stable isotope dilution
analysis (SIDA). The amount is calculated in μg extracted into the
cup and standardized towards the amount found at the end of the
extraction experiment (150 mL). As the coffee odorants have a
different concentration in-cup, appropriate dilutions need to be
prepared. Moreover to obtain a good chromatographic separation
with GC–MS, operating in single ion monitoring mode, the analysis
was split into two groups of analytes (Table 1). Sample preparation
was carried out in triplicate for each extraction volume. The overall
variability of the analysis was less than 10%.