Anew technique: Moving Chromatographic Window; Application to Separation of Aflatoxins B1, B2, G1 and G2, and Mathematical Modelling of Separation

Thin Layer Chromatography (TLC) is the first analytic technique used in aflatoxin detection and quantification, at late 1990 a more sophisticated equipment, HPLC became dominant in the analytic area because of the resolution power of the separation. Although the resolution of TLC can be increased by increasing the TLC Plate height, the velocity of solvent migration on plate drops reversely proportional of the square of solvent front height on the plate. When solvent movement distance increased from 12 cm to 17 cm, the chromatographic duration increases from 40 minutes to several hours. During the long period of the time, spreading of the spots increase drastically and resolution became poor again. In this study, Silica gel 60 coated aluminum TLC plates (20X20 cm, Merck 5553) and Tetry methyl Butyl ether: Methanol: water (480:15:5) is used for separation of Alflatoxin B1, B2, G1, and G2. Chromatographic separation is performed in a special narrow chamber (Turkish Patent Number TP2007/08721). Location of solvent front and four aflatoxin spots are determined and the migration rates are calculated periodically. Then the rates of their migration versus migration distance from application points are mathematically modeled. Assuming that solvent level in the chamber is increased as fallowing the Alflatoxin G2 spot 2 centimeter below, a chromatogram part (a chromatographic window) including aflatoxins region, rises upward through the chromatographic process and solvent moving distance never exceed 5 cm. Excel simulation of the process showed that in classic TLC process for developing distance 17 cm solvent can reach the top of the plate in 3 hours and aflatoxin B1 spot can arrive 9.3 cm height, but in the moving chromatographic window application, the duration can decrease about to one hour and aflatoxin B1 spot can reach 10.1 cm. Because of less spreading resolution of aflatoxins is excellent according to the classical process.

کلیدواژه ها:

Aflatoxins ، TLC ، chromatography ، mathematical modeling ، moving chromatographic window