Vol 71, No 5 (2016)

The chromatography techniques are partially characterized by presence of two phases (stationary and mobile), which allows identification, semi-quantification or quantification of important compounds in different matrices. Among chromatography methods, the thin-layer chromatography (TLC) must be considered for using in routine laboratories due to a number of advantages such as practicality, fast results and effectiveness, low cost, and simultaneous determination of analytes. This review describes the application of this technique to foods of animal origin, as well as compares TLC with other chromatographic methods. TLC has a strong potential as a surrogate chromatographic model for qualitative and quantitative analysis. Therefore, several modifications have been carried out to the conventional TLC system. Nevertheless, further studies should be performed in order to contribute with the scientific community and propagate the TLC method, which has performance and economic advantages compared to other chromatographic techniques.

Using the noncovalent immobilization of some thiacalix[4]arene derivatives on the surface of silanized silica, we obtained efficient adsorption materials for the extraction of Eu(III) ions from aqueous solutions of medium mineralization. The specific surface area of the adsorbents is 200–370 m²/g. It is shown that adsorbents containing thiacalix[4]arenes with phosphoryl groups selectively extract up to 99% of europium ions from aqueous solutions at pH 5.5–6; they are characterized by adsorption capacity of 7.5–14.5 mg/g and high distribution coefficients. The studied adsorbents exhibit high selectivity with respect to Eu(III) ions, wherein the distribution coefficients for Cs, Sr, Tb(III), Sm(III), Gd(III), La(III), and UO₂²⁺ are five times or more smaller.

Concentrations of zinc and cobalt in beer, mineral water, beets, cheese, potatoes, and soil are determined by potentiometry, using film Zn(NCS)₄^2- and Co(NCS)₄^2--selective electrodes based on higher quaternary ammonium salts. The developed electrodes enable the determination of zinc and cobalt in concentrations lower than their maximum permissible concentrations (MPCs). The procedures do not require complex or long sample preparation or expensive equipment. The results agree well with the data of atomic emission spectrometry and atomic absorption spectrometry.

The main sources of errors in the determination of isotope ratios in multielement laser mass spectrometry are considered. The optimum operation conditions of the laser source and measurement and processing of analytical signals, ensuring the reduction of relative errors of the determination of isotope ratios to the values of several tenths and hundredths of percent are proposed.

The rise in crime associated with the illicit trafficking in narcotics and psychotropic substances is one of the most severe problems in Russia today. In recent years, cases of using seeds of poppy plant “masked as food,” the bulk of which contains macroparticles of poppy straw visible to an unaided eye and which can be used as raw materials for the preparation of narcotic substances have become more frequent. In his work, using a Delta V Advantage isotopic mass spectrometer, we proposed criteria based on which tone can reveal artificial superinducements of poppy straw into “food” poppy seeds or their absence.

A rapid, effective method through an orthogonal design was developed, and four lignanoids were determined by HPLC and confirmed by HPLC coupled with electrospray ionization and quadrupole timeof-flight mass spectrometry (HPLC-ESI–QTOF-MS). The roots, stems and leaves of Zanthoxylum armatum DC were extracted by methanol for 15 min under reflux. Separation was performed using an UPLC system to quantify four bioactive compounds, namely fargesin, asarinin, planispine A and planispine B, in 12 batches of samples of different origin from China. Furthermore, the samples were analyzed using HPLC-ESI–QTOF-MS to confirm the results. The calibration curves of all four analytes showed good linearity (R > 0.998). Accuracy, precision and repeatability were all within required limits. The mean recoveries measured at the three concentrations were higher than 99% with RSDs lower than 4.1%. The established HPLC-DAD method could serve as a rapid and effective method for quality evaluation of Zanthoxylum armatum DC.