Vol 79, No 9 (2024)

The second and final part of the review. General information is provided on extraction under sub- and supercritical conditions (liquid extraction under pressure, subcritical water extraction, supercritical fluid extraction), the matrix solid-phase dispersion method and the QuEChERS method. Based on the analysis of the review papers, information on the specifics of sample preparation using these methods is systematized, experimental parameters affecting the extraction efficiency are considered, examples of the use of these methods for the isolation of organic compounds in the analysis of solid environmental objects, food and plants are given.

The use of the crosslinked polyvinyl alcohol–magnetite composite films as sensitive elements for determining the composition of aqueous solutions by digital colorimetry is described. A new approach to the production of composite materials of the composition hydrophilic polymer–magnetite by precipitation of Fe₃O₄ particles in ammonia vapor is proposed. The sensor films obtained in this way were used to determine the volume fraction of alcohol in products with a high alcohol content. The limit of ethanol determination was 63 vol.% isopropanol – 24 vol.%. The proposed sensory materials have been tested in the analysis of liquid hand antiseptics.

Single-charge background argid ions ArH⁺, ArN⁺, ArO⁺ and Ar₂⁺ create very strong spectral interference in elemental and isotope analysis by inductively coupled plasma mass spectrometry (ICP-MS). The behavior of these basic background argid ions under ICP-MS conditions is experimentally investigated depending on the high-frequency plasma power and the velocity of the argon transporting stream. Theoretically, the behavior of these argid ions has been studied by thermodynamic modeling with varying plasma temperature and velocity of the transporting argon stream. The general patterns of changes in the intensity of the main background argid ions and the efficiency of their formation with varying operational parameters of inductively coupled plasma are noted. A good coincidence of the experimental and theoretical dependences obtained has been achieved.

A composite based on Fe₃O₄ nanoparticles, graphene oxide and ionic liquid (1-butyl-3-methylimidazolium-2-carboxylate) is proposed as a sorbent for the extraction of bisphenol A (BPA) from bottom sediments by matrix solid-phase dispersion (MSPD). The saturation magnetization of the synthesized sorbent was 34 emu/g. Grinding of bottom sediments and subsequent grinding with the sorbent was carried out in a ball mill. Some stages of MSPD are partially automated, in particular the procedures of magnetic separation, BPA desorption and sorbent regeneration. The degree of extraction of BPA under experimentally selected conditions (sorbent weight is 0.5 g, the time required for grinding the sorbent is 5 minutes) is 94%. The sorbent can withstand four sorption-desorption cycles without loss of sorption capacity. To clean the matrix from interfering influences, washing with n-heptane is proposed. Bisphenol A was determined by gas chromatography-mass spectrometry after derivatization with acetic anhydride. The analytical characteristics of the method were established using model samples of bottom sediments that artificially polluted BPA. The limit of determination by the developed method was 0.1 μm/kg, the linearity interval of the calibration graph was 0.3–12 μm/kg (r² = 0.994). The bottom sediments selected near the discharge of the Voronezh wastewater treatment plants (Voronezh River and Don River) were used as real objects for analysis. The concentration of BPA in bottom sediments was 3.83–6.52 μm/kg.

A method for manufacturing a glass-carbon electrode with electrodeposited palladium particles and a molecular imprinted polymer from nicotinamide for the determination of dopamine in the presence of structurally related compounds has been developed. The use of a polymer with specific recognition centers complementary to the template molecule led to an increase in the sensitivity and selectivity of dopamine detection. Immobilization of palladium particles on the electrode surface made it possible to increase the selectivity of the voltammetric determination of dopamine in the presence of adrenaline and norepinephrine. The potential difference of the oxidation peaks of these compounds is 200 mV. The linear bilogarithmic dependence of the analytical signal on the dopamine concentration is observed in the range from 5.0 × 10^–9 to 5.0 × 10^–3 М. The proposed method was tested in the analysis of urine samples.