The aflatoxins, carcinogenic and toxic mold metabolites
of Aspergillus flavus, were isolated and determined
in cottonseed meal and other feedstuffs. This new
quantitative method uses an acetone soxhlet extraction to
remove the toxins from the defatted meal. The residual
triglycerides, phospholipids and pigments were removed
from the acetone by filtration of the cooled solution.
The aflatoxin was further isolated by evaporating the
acetone and redissolving the residue in hot methanol.
After cooling, the insolubles were discarded and the
methanol-soluble materials taken up in chloroform. The
chloroform solution was spotted on silicic acid thin layer
chromatographic plates along with suitable standards.
After development with 9:1 (v/v) chloroform:acetone, the
chromatographic plates were examined under ultraviolet
light.
Complete recovery of aflatoxin, within limits of
visual discrimination, was obtained by this isolation procedure as indicated by extraction efficiency and internal
standard data. Twenty-five cottonseed meals were
analyzed by this method and nine meals contained aflatoxin
B₁ at levels from 17 to 190 parts per billion.
Fluorodensitometry, a new instrumental technique,
was used to compare standards and samples containing aflatoxin
directly from the thin-layer chromatographic plate.
This procedure eliminates the errors inherent in the
visual comparison method and permits greater sensitivity
and accuracy. Amounts of aflatoxin B₁ as low as 8.0 x
10⁻⁵ micrograms can be detected by this technique.
The results obtained by this procedure were substantiated
by duckling assay and trout feeding trials. / Graduation date: 1966
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27122 |
| Date | 12 May 1966 |
| Creators | Ayres, James Lee |
| Contributors | Sinnhuber, Russell O. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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