Graduation of AMR-1006M NMR analyzers using natural samples and samples-imitators

Abstract

The article presents the results of the study of the metrological characteristics of NMR analyzers AMV-1006M obtained during their calibration to determine the mass fraction of oleic acid in sunflower seed oil using sunflower seeds and specially developed reference materials (RM) - imitators of the mass fraction of oleic acid in seed oil. When calibrating an NMR analyzer under repeatability conditions, it was found that the relative standard deviations of the measurement results and the limits of the confidence random error of the measurement results using RM simulators are almost 3 times lower than the results of the measurement with use of natural sunflower seeds. When checking the reproducibility of the calibration results using four NMR analyzers, it was found that the reproducibility of the calibration of NMR analyzers using RM simulators of the mass fraction of oleic acid is more than 3 times better than when using sunflower seeds. The data obtained is explained by the fact that RM-simulators have a fairly homogeneous structure, which is formed during their manufacture. Sunflower seeds are a complex heterogeneous system with a heterogeneous structure in the volume of the analyzed sample. The study of the effect of temperature on the calibration results showed that the standard deviation of the measurement results for RM-simulators does not exceed 0.8 % abs., while the using of natural seeds, values of 2.5 % abs. were obtained. Thus, the use of RM simulators can significantly reduce the calibration error of NMR analyzers associated with the effect of temperature. The obtained data confirmed the expediency of using for calibration of the AMV-1006M NMR analyzers precisely CO-simulators of the mass fraction of oleic acid.