An HPTLC method for confirmation of the presence of ultra-trace amounts of aflatoxin M_1 in human urine

摘要

A TLC method has been developed for confirming results from determination of aflatoxin M_1 in human urine. Urine samples were cleaned on immunoaffinity columns and analyzed by means of an immunochemical method (ELISA). Results higher than 5 ng L~(-1) urine were confirmed by instrumental HPTLC on silica gel layers with fluorescence detection. Chloroform-acetone-2-propanol, 85 + 10 + 5, was used as mobile phase. The chromatogram was scanned in reflectance mode at #lanbda# = 366 nm with #lanbda# = 400 nm measuring filter; SENS and SPAN parameters were 175 and 60, respectively. Twofold enhancement of the sensitivity of the HPTLC method was achieved by immersion the chromatographic plate in a solution of paraffin oil in n-hexane. Recoveries were 75-85% in the range 20-100 ng L~(-1) urine. The average relative standard deviation of repeatability (RSDr) was 8.2%. The limit of quantification (LOQ) of aflatoxin M1 in urine was 5 ng L~(-1). Validation of the method was performed according to the principles used for HPTLC methods.