Determination of heavy metals in sunflower seeds by atomic absorption spectroscopy based on fractional mineralization
Vestnik Voronežskogo Gosudarstvennogo Universiteta Inženernyh Tehnologij
The actual problem of food chemistry is the contamination of food raw materials and food products with heavy metals. Modern physico-chemical methods for the quantification of heavy metals are highly accurate and allow even trace amounts of elements to be determined, but the complexity of the sample preparation procedure is one of the most time-consuming steps, requiring high costs of reagents and time, especially for analysis of fat-containing samples. In this regard, development of new ways of
... ment of new ways of determination of content of heavy metals in olive raw materials is relevant. Sunflower seeds in which they established the maintenance of toxic elements with use of different ways of sample preparation have acted as an object of a research: dry combustion and a wet mineralization and the developed new way of a fractional mineralization which distinctive features are: preliminary decomposition of test on fatty (oil) and fat-free (oilcake) of fraction with their independent mineralization. Oilcake is exposed to combustion at the maximum temperature 400 ?С for two full cycles, with convertion of the mineralizat in background solution and definition of metals by AAS-ETA method, oil – is dissolved in bipolar solvent in the ratio 1:6:2 from the mass of oil, with the subsequent direct input of mix in an analytical cell of the graphite tubular furnace of an electrothermal atomizer where there is a mineralization and simultaneous atomization of test. The use of fractional mineralization makes it possible to improve the metrological characteristics of the atomic absorption method of sunflower seeds: to increase the average openability of the investigated elements to 90.8%, to reduce the error of convergence (by 4.5%) and the reproducibility (by 4.9%) of the results of the study of cadmium and lead, and also to reduce the total time of sample preparation for 4–6 hours as compared with the test methods.