A new method for the rapid determination of volatile substances: the SPME-direct method: Part I: Apparatus and working conditions

A new method for the measurement of volatile substances constituting the odors of food or other material is presented. The apparatus developed consists of a standard injector, as used for gaschromatography, linked directly to a detector without a separating column. The headspace is produced in a vial and sampled by a solid phase micro extraction (SPME) fiber. The volatile substances on the SPME are desorbed directly into the detector and the signal is quantified. The detectors tested are the flame ionisation detector (FID) and the nitrogen phosphorus detector (NPD). Other detectors can also be adapted. The signal obtained consists of a single peak, which is directly proportional to the concentration of the headspace volatiles. The reproducibility of the measurement for standard mixtures, as measured by their variation coefficient, is about 2.4%.