No abstract

No abstract

No abstract

No abstract

Rapid voltammetric procedures for the determination of water-soluble vitamins C, B 1 , and B 2 , fat-soluble vitamin E (a-tocopherol acetate), and quercetin in bioactive food additives have been developed. The systematic error (i.e., correctness) of the proposed procedures was evaluated using certified reference materials and the additive recovery tests, which gave the following limiting metrological characteristics: relative error, 25 %; reproducibility, 28 %; convergence, 22 %. The full analysis time (with sample preparation) did not exceed 2 hours. Voltammetric determinations under optimum conditions can be performed in the automated regime controlled by a computer according to the specially developed software. 166 0091-150X/05/3903-0166

Conditions were selected for the voltammetric determination of streptomycin and azitromycin using electrodes of different types. The interfering effects of cations, anions, and organic substances, food proteins among them, on the analytical signals from antibiotics were estimated. Procedures for determining streptomycin and azitromycin in pharmaceuticals and for determining streptomycin in milk at nano levels were developed.

No abstract

Express procedures of quantitative determination of uric acid, phenol, aniline, dyes on a basis of indium chloride phthalocyanine in food-stuffs, polyvitaminic preparations, drinking water, plastics applied for production of toys, plates and dishes as well as in technological mediums on the level of normative documents have been suggested. All calculations and treatment of analysis results have been carried out with the help of computers by programs made according to the certification program of quantitative chemical analysis methods (QCAM).Chemical synthesis of food-stuffs and their components, expansion of assortment and increasing production of food-stuffs make high demands of control of production quality and of improving vitamins determination methods.Indices magnitudes of food value of products by content of water-soluble vitamins B1 (thiamine) and B2 (riboflavine) are fluctuating in a very wide range and are determined for some kinds of products by minimum content of B1 0,Ol and B2 0,02 mg/100 g.The procedures of vitamins quantitative determination in food-stuffs used presently and recommended by normative documents involve a great number of optical methods variants [l-21. In order to determine thiamine fluorometric method is used, as a rule, based on oxidation of thiamine by potassium ferricyanide in alkaline medium resulted in high-fluorescent in UV-light compound of thiochrome, which fluorescence intensity is directly proportional to thiamine content.Uncombined riboflavine and the product of its photolysis -lumiflavine -have characteristic yellow-green fluorescence when their solutions are radiated by the light of length wave 440 -500 nm. The method is used in two variants. One of them -the variant of direct fluorometry -is based on a determination of fluorescence intensity before and after reduction of riboflavine by sodium hydrosulphide. The second variant -lumiflavinic -is based on a use of the property of riboflavine to transform into lumiflavine when radiating in alkaline medium. Fluorescence intensity is measured after its extraction by chloroform [2]. Determination of riboflavine and thiamine by these methods requires great labour expenditures: a great number of sample treatment operations, reagents (more 20 names) and expensive enzymes. The procedures are long-term (more 2-3 twenty-four hours).Long-term method for determination of vitamins B1, B2, C is voltammetry method, to our mind, and first of all such its high-sensitive variants as stripping voltammetry (SVA). Advantage of SVA consists in a possibility to work with a little by mass and volume samples with a high express owing 0-7803-5729-9/99/$10.00 0 1999 IEEE