Application of zNosetrade mark for the analysis of selected grape aroma compounds.

A novel and portable gas chromatograph (GC, zNosetrade mark) has been evaluated for the measurement in grape berries of selected six-carbon compounds; namely, hexanal, cis-2-hexen-1-ol, cis-3-hexen-1-ol and trans-2-hexenal. The zNosetrade mark is a handheld GC which uses purge and trap for concentration, and has a surface acoustic wave (SAW) sensor as a detector. Operation of the zNosetrade mark using direct aspiration of the sample failed to detect the compounds at the reported odour threshold values. Pre-concentration by Tenax((R)) trapping and solid-phase microextraction (SPME) were investigated to improve the zNosetrade mark sensitivity. Use of a Tenax((R)) pre-trap with the zNosetrade mark allowed detection of the compounds at concentration levels in the order of their threshold values. Excessive bleed from the SPME fibre prevented the use of SPME with zNosetrade mark.