Anhand der Literatur und eigener experimenteller Arbeiten wird über das Vorkommen von Aflatoxin in Lebensmitteln, über seine biologische Wirkung, über Bestimmungsmethoden sowie über Möglichkeiten der Entgiftung berichtet.
The fluorescence micromethod of aflatoxins B,, B,, G, and G, determination in solution is described. The amount about 0.1 kg of aflatoxins B, and GI, and 0'01 pg of aflatoxins B, and G, in one spot after elution with methanol can be determined, with accuracy about 5%. The results of described fluorescence method are in agreement with results of spectrophotometric, fluorodensitometric and visual determinations. A very strong influence of light on results of aflatoxins B, and G, determination was stated. Photodecomposition of aflatoxins B, and G, to several photoproducts was observed.In our previous paper [I] we described the occurrence of aflatoxins ingrain crops and other products, their biological effect, methods of determination and detoxification.The methods of determination of aflatoxins are based mainly on their ability to light absorption and fluorescence emission. The quantitative analysis by fluorescence method can be effected by visual evaluation directly on the chromatoplates, or fluorodensitometrically. Because of its subjectivity the first method gives inaccurate results. The second requires an expensive and complex equipment including a self-recording fluorodensitometer and an integrator enabling the calculation of concentration of individual aflatoxins from the surface of cones. A good separation of spots is required besides. This is why an attempt was made to apply the measurements of fluorescence after the elution of spots from the silica gel with methanol [2].
The simple method for determination of small amounts of aflatoxins (about 5 -10 yg/kg) was described. The method was adopted for wheat, barley, rye and oats. Difficulties of aflatoxins determination in cereals are discussed, mainly observed during purification of extracts and resolution by TLC. Different tests were compared for confirmation of aflatoxins in cereals.Results of cereal crops control for contamination with aflatoxins are presented.The differences between results obtained in collaborative studies on the determination of aflatoxin in corn are very considerable, especially for samples of corn with content of toxins lower than IOO Fg per kg [IS, 211. Standards admitted by WHO, on contents of aflatoxins of about 10 yg per kg request the elaboration of considerably more sensitive methods. The detection as well as the precise determination of such small amounts of aflatoxins in a sample creates additionally analytical difficulties. In the greater part of products contaminated by aflatoxins there is a considerable amount of impurities which make impossible their determination without a previous thorough removal of the impurities from the extract [I, 4, 6 , 8-10, 12, 13, 15, 16, 20, 221.As it appears from literature information and from our own experience the reasons for the diversified results in the quantitative determination of aflatoxins by chromatographic methods can be listed as follows:I. Distribution of aflatoxins material is often not uniform. Such a distribution causes considerable differences in the results of parallel average samples. 2. Losses during the extraction caused by the use of improper solvents for instance in methanol by decomposition under influence of light, etc. 3. Losses during the purification on chromatographic columns. 4. Improper resolution on thin-layer chromatograms.5. Decomposition on chromatograms especially under the influence of light.6. Masking the fluorescence of aflatoxins spots by impurities which fluoresce or quench the fluorescence, especially in grain extracts.Our investigations have confirmed these observation;, because in each stage we have stated losses of aflatoxins. For this reason we have controlled on each stage (extraction, purification, TLC resolution and fluorodensitometry) in order to find out the causes of the losses.We also investigated the possibility of a most simple method elaboration for aflatoxin control in grain crops.
The method of aflotoxins M, and M, determination in presence of aflatoxins B,, B,, G, and G, is presented. The fluorescence properties of aflatoxin M, and M, are discribed. A simple method of aflatoxin M extraction is proposed. Results of different tests for confirmation of aflatoxins M are discussed. During control of powdered milk from three factories aflatoxins M were not detected in final products. As aflatoxins M, and M, usually accompany aflatoxins B,, B,, G, and G, as well as their other metabolites present mainly in milk and milk products it is reasonable to determine in the samples affected by mould simultaneously all six mentioned toxins [I, 3, 8, 9, 101. To achieve this simultaneously the determination of all six toxins has been carried out in order to choose the most convenient method for extraction, purification and chromatographic separation. Further more there have been examined the fluorescent properties of the aflatoxins MI and M, in solutions and on chromatograms. Material and MethodsA quantitative standard of the aflatoxin M, having a concentration of 10,14 pg/ml and moreover a standard of the aflatoxin M, having a concentration 6,o Fg/ml. These standards have been received from the Northern Marketing and Nutrition Research Division, Fermentation Laboratory Peoria, Illinois. A qualitative standard of the aflatoxin M,, from the Central Veterinary Laboratory, New Haw Weybridge Surrey, England. Echtblausalz B (fast blue salt B for chromatography) from the firm Merck (di-o-anisidine, tetrazolium chloride).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.