Characterization of surface treatments of cork stoppers by FTIR-ATR.
A general method is described for the identification of paraffin- and silicone-based surface treatments applied to single-piece natural and 1 + 1 (cork agglomerate with two natural cork disks) cork stoppers used 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 seven wavelength 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. Univariate analysis of the results enabled identification of stoppers that had received surface treatment by measuring 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 this technique, we constructed a mathematical model using the seven bands studied. The model correctly classified 100% of the stoppers used to construct it and 91.7% of the stoppers used for validation.
Ortega-Fernandez
Catalina
C
INIA, Carretera de la Coruña, km 7.5, 28040 Madrid, Spain.
Gonzalez-Adrados
José R
JR
García-Vallejo
María C
MC
Calvo-Haro
Rosa
R
Caceres-Esteban
María J
MJ
D016002:Discriminant Analysis; D018857:Food Packaging / Q000379:methods*; D008962:Models, Theoretical; D010232:Paraffin / Q000032:analysis; D012828:Silicones / Q000032:analysis; D017550:Spectroscopy, Fourier Transform Infrared; D014920:Wine
D012828:Silicones; D010232:Paraffin