Coupling MOS sensors and gas chromatography to interpret the sensor responses to complex food aroma: Application to virgin olive oil

This paper describes a novel approach to determine the individual contribution of volatile compounds to the overall sensor responses of metal oxide semiconductor (MOS) sensors when they are applied to a complex mixture of compounds such as food aroma. A methodology entailing the use of a sensor array or electronic nose (EN) as non-destructive detector in-parallel with the flame ionization detector of a gas chromatograph (GC) is described and illustrated in the context of virgin olive oil aroma analysis. Aspects related to the experimental set up and data processing are examined. The capability of gas chromatography for obtaining qualitative and quantitative information of the volatile compounds present in virgin olive oil was used to find relationships between these compounds and the sensor responses by means of a coupled system GC–EN. The sensor responses that resulted from this coupling (sensorgrams) served to prove the sensor sensitivity to alcohols, aldehydes, and those compounds that are responsible to sensory defects in virgin olive oil (e.g. aldehydes and acids).