文摘
A general method is described for the identification of paraffin- and silicone-based surface treatmentsapplied to single-piece natural and 1 + 1 (cork agglomerate with two natural cork disks) cork stoppersused to seal wine bottles. The method is based on Fourier transformed infrared spectroscopy (FTIR)and attenuated total reflectance (ATR) analysis of ready-for-use stoppers. The absorbance in sevenwavelength bands selected as the most characteristic (2916 and 2850 cm-1, for paraffins, and 2963,1258, 1079, 1010, and 787 cm-1, for silicones) was measured for both kinds of stoppers. Univariateanalysis of the results enabled identification of stoppers that had received surface treatment bymeasuring the absorbance in two of the selected bands, representing paraffins and silicones,respectively. The type of surface treatment used was identified by discriminant analysis. Using thistechnique, we constructed a mathematical model using the seven bands studied. The model correctlyclassified 100% of the stoppers used to construct it and 91.7% of the stoppers used for validation.Keywords: Cork stopper; surface treatment; paraffin; silicone; quality control; FTIR-ATR