METHOD AND DEVICE FOR CHARACTERISING AN ANALYTE

A method and apparatus are provided for characterizing a product sample for example in comparison to a reference sample using a sensor such as a gas chromatograph or a MOS sensor. This characterization may comprise an indication of whether or not the product sample conforms to a quality criterion. The comparison of the sensor output measurements for the product sample is compared to maximum and minimum value curves, which may be derived from measurements of the reference sample, whereby adjacent samples outside the envelope defined by these maximum and minimum values are grouped together. A dissimilarity index may be determined for the anomalous values as a whole, or on a per group basis. The groups may be classified depending on the shape they describe, in particular the presence, or not, of peaks, and correspondingly the shape of the corresponding part of the envelope. These determinations may then be used as the basis of the conformity indication, and also the basis for attempting to identify the cause of any anomalies, in particular the identification of foreign components.