Confirmation of Identity of Aflatoxins

To confirm the identities of aflatoxins B1 and G1 a technique has been devised which uses derivative formation on the TLC plate. The sample extracts and standards are spotted on the origin line of the plate and 1 |L amounts of trifluoroacetic acid are then added to each spot. After reacting for 5 min, the trifluoroacetic acid is removed by blowing air at 35-40°C on the plate for 10 min. The trifluoroacetic acid catalyses the addition of water across the double bond in the terminal furan ring of aflatoxins B1 and G1 to form the derivatives called aflatoxin B2a and G2a, which give lower RF values than the parent compounds. The plate is developed with chloroform-acetone (85 : 15 v/v). Upon examination of the plate under ultraviolet light at 365 nm, sample and standard will have low RF blue and green spots of the derivatized aflatoxins. Since aflatoxin B2 and G2 do not have the unsaturated double bond, they will be unaffected by the test and will appear at their normal RF values. For additional confirmation the plates can be sprayed with sulfuric acid-water (1:3 v/v), which causes the aflatoxin spots to change from blue or blue-green to yellow fluorescence.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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