Comprehensive study of the composition of fish fat extracts and quantitative criteria for distinguishing standardized omega-3 polyunsaturated fatty acids extracts

Background Effects of drugs and biologically active supplements based on omega-3 polyunsaturated fatty acids (ω3 PUFA) considerably depend on the standardized content of eicosatetraenoic acid (EPA), docosahexaenoic acid (DHA), and other fatty acids in the extracts.Material and methods In this study, we comprehensively examined the composition of 10 ω3 PUFA samples with chromatographic measurement of more than 40 metabolites of fatty acids and other compounds. The data on extract composition were analyzed with current methods of intelligent data analysis (metric condensation method; multidimensional scaling; principal component analysis with axis identification; topology-metrical approach to recognition).Results Quantitative markers were obtained, which allowed separating the standardized ω3 PUFA-based samples (Omacor, Solgar omega-3 700, Femibion Natalker-2, Omega-3 concentrate, Omegamama) from less standardized ones (Fish oil-Teva, Omegatrin, Omeganol, etc.) based on results of a chromatographic analysis of fatty acid composition in the studied samples (EPA+DHA marker, ω6+ω11 marker, and standardization coefficient showing conformity of measured ω3 PUFA levels with the content stated by the manufacturer).Conclusions Among the studied samples, the pharmaceutical product Omacor showed the best values of standardization indexes.

METHODOLOGICAL RECEPTION FOR DETERMINATION OF DICAMBA RESIDUES IN SOYBEANS BY GC-MS

Introduction. In this paper, there are presented results of investigations on the development and validation of the method for the determination of dicamba residues in import foodstuff (soybeans). The identification and quantitative determination of dicamba are performed by capillary gas-liquid chromatography with mass-selective detection (ionization-electron impact). Material and methods. The stages of sample preparation include four steps as extraction with acidified acetonitrile, followed by the filtration and evaporation; freezing the sample with filtration and evaporation; dissolving the dry residue in a mixture of acetone: water (1:20); purification by repeated redistribution in a system of immiscible solvents under varying the pH of the aqueous medium (pH 9-10: dichloromethane, hexane, pH 2: hexane-tert-butyl methyl ether). The chromatographic measurement was preceded by the derivatization of the acid to the corresponding methyl ester by the treatment with a solution of diazomethane in diethyl ether Results. The lower limit of the quantitative evaluation of dicamba in samples of soybean beans is of 0.01 mg/kg, the signal-to-noise ratio at the detection limit accounts of 20:1. The completeness of extraction of dicamba, established on the basis of analysis of model samples with the introduction of a substance at four points within the defined range, amounted to 85-95%. The average quadratic deviation of the repetition varies in the range of 3.3-4.9%. Discussion. The use of diethyl ether containing dibutylhydroxytoluene (6 ppm) as a stabilizer, as well as the interfering effect of phthalates, led to the formation of poorly resolved peaks of the methyl ester of dicamba, dibutylhydroxytoluene, and dibutyl phthalate. The combination of the use of different methods of data collection (in the scanning mode and in the mode of recording individual ions) made it possible to identify these components. Replacement of the used diethyl ether, as well as variation of chromatographic conditions, for separation of dicamba and phthalate peaks, made it possible to achieve the necessary selectivity of detection of the analyte.

Validation of a Method for Determining Cholesterol in Egg Yolks/ Walidacja metody oznaczania cholesterolu w żółtkach jaj

The aim of the study was to validate a gas chromatographic method for determining cholesterol in egg yolks according to the EN ISO/IEC 17025 standard. Of the two methods, with and without internal standard, the former was characterized by lower uncertainty, with a repeatability of 4% and within-laboratory reproducibility of 6%. The method’s uncertainty (n = 2, P≤0.05), which included sample preparation errors and chromatographic measurement errors, was 10.6%. Mean recovery was 99.9% and limit of quantification was 0.16 mg/g. The coefficient of variation for repeatability, which is calculated during routine analyses, should not exceed the 8% limit of repeatability. The method is reliable, as confirmed by the results of validation, and the procedure is relatively rapid and simple.

Effect of Temperature on Oil-Gas Separation in Membrane Separation Based Transformer On-Line Monitoring

In the same conditions, the transformer on-line monitoring and off-line chromatographic analysis should be consistent, but the actual on-line monitoring is effected by the ambient temperature to make it is different from the off-line chromatographic measurement. this paper analyzes the theory of oil-gas separation, and develops a gas-oil separation test platform first, conducts an experiment about the changes of temperature based on the device, and then compares with the data of off-line measurement, gets the law of temperature affection on the oil-gas separation process, Finally gives the reason of influence of ambient temperature on oil-gas separation in on-line monitoring.