Rapid analysis of methanol in grape-derived distillation products using near-infrared transmission spectroscopy.
Samples of distillates derived from the production of wine-fortifying spirit were analyzed for methanol by gas chromatography (GC) and near-infrared spectroscopy (NIRS). NIRS calibration models were developed which could accurately predict methanol concentrations in samples of fortifying spirit that had been produced over a period of three years from four different commercial distillation facilities. The best accuracy of the predictive models, as measured by the standard error of prediction value, was 0.06 g/L methanol. Other distillation fractions, produced during preparation of commercial fortifying spirit, were also examined. The most useful NIRS calibration models used partial least squares regression on continuous spectra from a scanning instrument, but it was demonstrated that calibrations could also be developed with a smaller number of fixed wavelengths, using multiple linear regression models. NIRS offers the advantages of rapid analysis, with simple routine operation, and may offer the potential for in-line process control in the operation of a commercial distillation facility.
Dambergs
Robert G
RG
The Australian Wine Research Institute, P.O. Box 197, Glen Osmond, SA 5064, Australia. bob.dambergs@awri.com.au
Kambouris
Ambrosias
A
Francis
I Leigh
IL
Gishen
Mark
M
D002138:Calibration; D002849:Chromatography, Gas; D000431:Ethanol / Q000032:analysis; D016014:Linear Models; D000432:Methanol / Q000032:analysis*; D019265:Spectroscopy, Near-Infrared; D027843:Vitis / Q000737:chemistry*; D014920:Wine / Q000032:analysis
D000431:Ethanol; D000432:Methanol