Influence of densitometer and video-documentation settings in the detection of plant phenolics by TLC

The influence of densitometer and video TLC-documentation system settings h as been studied, Two different mixtures of phenolic compounds, either pheno lic acids and flavonoids or coumarins, served as test mixtures, The ethyl a cetate-soluble fraction of a methanolic extract of Phyllanthus emblica L, l eaves was used as an example of plant material containing phenolic compound s. TLC was performed on normal-phase (NP) and reversed-phase (RP) precoated layers, Compounds were separated in Camag twin-trough or horizontal develo pment chambers. The settings tested for a dual-wavelength, flying-spot UV d ensitometer (Shimadzu CS-9001 PC) were the beam slit-size and data accumula tion by reflectance mode. The CCD (charged-coupled device) video camera set tings tested in the video image-analyzing system (Camag video documentation system with the Reprostar 3) were the resolution (DTL), frame accumulation (= data accumulation), integration period, and aperture. The results from the optimum densitometric measurements were compared with those obtained by use of the CCD video camera to determine the repeatability of these two de tection methods, According to the analyses these two methods can be regarde d as equivalent for the detection of phenolic compounds at wavelengths of 2 54 nm and 366 nm.