2. Evaluators

Evaluators are of paramount importance in GC/O. As the instrument's true detectors, they must be reliable, robust, repeatable and reproducible. Their selection, training and evaluation must follow a number of best practices. For this, it is common practice to follow the recommendations given for sensory analysis, such as the ISO or AFNOR standards [23] . Evaluators need to be placed in the right conditions. This means using a closed room, isolated from noise and olfactory disturbances. It must be equipped with ventilation and air-conditioning to maintain a pleasant, odor-free atmosphere. The decor should be neutral, and the lighting soft and subdued, to help assessors concentrate.

For some methods, judges don't need any special training. Nevertheless, a good familiarity with the...