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Supercritical Fluid Extraction and Characterisation of Urtica Dioica L. Leaves Pigments
Sajfrtová, Marie ; Sovová, Helena ; Bártlová, Milena ; Opletal, L.
Extraction and fractionation of green and yellow pigments from stinging nettle leaves was studied using ethanol-modified carbon dioxide as a solvent. The extracts were analysed by means of HPLC and RP-HPLC systems. The effect of operation conditions was analysed in a series of experiments at pressures from 20 MPa to 28 MPa, temperatures between 25 °C and 60 °C, and ethanol concentration in CO2 between 0 and 7.4 wt.%. The main result was that the best conditions for the supercritical fluid extraction of pigments were ethanol concentration in CO2 4.5 - 7.4 wt.%, temperature 40°C and pressure 28MPa and that degradation of pigments was eliminated with decrease of temperature of micrometer valve and addition of small amount of antioxidant to ethanol.
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Application of mica based pigments
Štengl, Václav ; Kalendová, A. ; Trojan, M.
Properties of sandwich pigments based on mica coated with metal oxide layers are described. Various mica types were characterized and used for pilot plant scale synthesis of pigments. Paints containing this kind of pigments were formulated and tested anticorrosive coatings. Synthesis and characterization of some thermally stable pigments based on mixed metal oxides is also described.
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