Molar absorptivities of aflatoxins B1, B2, G1, and G2 in acetonitrile, methanol, and toluene-acetonitrile (9 + 1) (modification of AOAC Official Method 971.22): collaborative study.
Four laboratories participated in a mini-collaborative study of AOAC Official Method 971.22, Standards for Aflatoxins, Thin-Layer Chromatographic Method, to extend the method to 3 replacement solvents for benzene for calibration of standard aflatoxin solutions. Triplicate test sample vials, each containing 25 micrograms of the respective aflatoxin for each of the 4 aflatoxins and for each of the solvents, were prepared and sent to each collaborator. The collaborators dissolved the aflatoxin in each vial in 2 mL solvent, measured the UV spectrum, and reported the absorptivity maxima near 350 nm. The concentrations of the aflatoxins in the test samples were determined by dissolving identical test samples in benzene-acetonitrile (98 + 2) and following the procedure described in AOAC Official Method 971.22. These concentrations were, in turn, used to determine the molar absorptivities in the other 3 solvents (see Table 1). AOAC Official Method 971.22 has been modified to extend its applicability to 3 replacement solvents for benzene for calibration of standard aflatoxin solutions.
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U.S. Food and Drug Administration, Division of Natural Products, Washington, DC 20204, USA.
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D000042:Absorption; D000097:Acetonitriles; D016604:Aflatoxin B1 / Q000032:analysis / Q000737:chemistry; D000348:Aflatoxins / Q000032:analysis / Q000737:chemistry*; D001554:Benzene; D000432:Methanol; D012015:Reference Standards; D012996:Solutions; D012997:Solvents; D013056:Spectrophotometry, Ultraviolet; D014050:Toluene
D000097:Acetonitriles; D000348:Aflatoxins; D012996:Solutions; D012997:Solvents; C027955:aflatoxin G1; C029754:aflatoxin G2; D014050:Toluene; C029753:aflatoxin B2; D016604:Aflatoxin B1; D001554:Benzene; D000432:Methanol; C032159:acetonitrile