Separation and tentative identification of the main pigment fraction of raisins by thin-layer chromatography-Fourier transform infrared and high-performance liquid chromatography-ultraviolet detection.
The soluble color pigments of raisin are separated by reversed-phase thin-layer chromatography (TLC), and the capacity of TLC-Fourier transform infrared (FTIR) with both on-line and off-line coupling is assessed for the identification of the main fraction. TLC has also been used as a pilot technique for the development of a gradient elution method for the separation of pigments by high-performance liquid chromatography (HPLC). On-line TLC-FTIR cannot be used for identification because of the strong adsorbance of the stationary phase. Off-line TLC-FTIR combined with the retention behavior of the main pigment fraction indicates that it is a polymer, caramel-like compound composed of erythrose and fructose monomers. Baseline separation of pigments is achieved by HPLC using TLC as a pilot method.
Cserháti
T
T
Institute of Chemistry, Chemical Research Centre, Hungarian Academy of Sciences, Budapest.
Forgács
E
E
Candeias
M
M
Vilas-Boas
L
L
Bronze
R
R
Spranger
I
I
D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002855:Chromatography, Thin Layer / Q000379:methods*; D005638:Fruit / Q000737:chemistry*; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared