Thin Layer Chromatography - Determination of Caffeine Using Both Densitometry Measurements and an Image Analyzing System 2


The scanner was operated in the reflectance mode with slit widths of 0.8 mm and 6 mm respectively the monochrometer band width was 30 nm (wavelength of maximum absorbance l=270 nm). The densitometry processing was carried out with a Camag TLC scanner II, equipped with a built-in twelve bit analog-to-digital converter and controlled by an external computer with a RS32 interface. The software used was the QTLC-pack (KIBK-IFC, 1990).


Courtesy of J. Planar Chromatogr.[ref.16]


Figure 30 Calibration Curves Obtained by Densitometer Measurements at 270 nm of a Caffeine Standard and the Image Analyzing System at 259 nm