Comparison of three methods for determining aflatoxins in melon seeds
DiProssimo, V.P.; Malek, E.G.
Journal - Association of Official Analytical Chemists 79(6): 1330-1335
1996
ISSN/ISBN: 0004-5756 PMID: 8946711 Document Number: 462777
The suitability of 3 methods for determining aflatoxins in melon seeds was examined. The first 2 are the Contaminants Branch (CB) method and the Best Foods (BF) method, both official methods for determining aflatoxins in peanuts and peanut products. The third method, the modified CB method-Rapid Modification of the Cottonseed (CB-RCS-Mod) method, devised in this work, was derived by combining steps from the CB method and the Rapid Modification of the Cottonseed method. The CB method was superior to the other 2 methods for quantitation of aflatoxins. It gave better recoveries and cleaner extracts that exhibit less fluorescent interference for thin-layer chromatography (TLC) than the BF method. Also, its solvent efficiency was better than that of the CB-RCS-Mod method. With the CB method, recoveries from spiked samples were 85.0% for aflatoxin B-1 and 90.0% for aflatoxin B-2. Recoveries of G aflatoxins were more variable, averaging 90.0% for aflatoxin G-1 and 72.5% for aflatoxin G-2. Total aflatoxin recovery was 86.5% for the CB method. At a low aflatoxin contamination level (8 mu-g B-1/kg sample), aflatoxin B-1 was detectable by the CB method but not by the BF method. Detection of aflatoxins in BF method sample extracts by TLC was not improved by the use of chloroform-acetone-water (88 + 12 + 1), benzene-ethanol-water, or ether-methanol-water (96 + 3 + 1) in place of the standard chloroform-acetone (88 + 12) developer. Use of ether-methanol-water (96 + 3 + 1) for detecting aflatoxins by TLC in the CB method extracts increased interference compared with the standard chloroform-acetone (88 + 12) developer.