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The possibility of formation of a ternary (sandwich) compound of a dialdehyde (malondialdehyde, glutaraldehyde, or glyoxal) with ethylenediamine fluorescein thiocarbamyl (EDF) and silica nanoparticles noncovalently modified with polyethyleneimine (Si[O.sub.2]/PEI) with the subsequent fluorimetric determination of the dialdehyde was demonstrated. The mixed Schiff base Si[O.sub.2]/PEI- dialdehyde-EDF (sandwich) is formed in an acetic acid solution on heating in a water bath. The sandwich and the excess of Si[O.sub.2]/PEI were separated from the unreacted fluorophore by centrifugation; the precipitate was washed and resuspended in water, and the fluorescence of solution was measured ([[lambda].sub.ex] = 470 nm, [[lambda].sub.em] = 520 nm). The duration of an analytical cycle was no longer than a half-hour. The limit of detection of dialdehydes in pure water is 1 x [10.sup.-5] M, and the analytical concentration range is 2 x [10.sup.-5]-3 x [10.sup.-4] M (for malondialdehyde). The repeatability RSDs in this concentration range were 3-5% (n = 3). The comparable concentrations of sulfamethoxazole, sulfadiazine, pyracetam, and chloramphenicol and 1 x [10.sup.- 5] M of ceftriaxone, ceftazidime, metamizole (analgin), isoniazid, and amikacin caused no interference with the determination of 3 x [10.sup.-4] M malondialdehyde; protein noticeably interfered. The determination of glyoxal and glutaraldehyde in disinfectants was carried out. Keywords: malondialdehyde, glyoxal, glutaraldehyde, fluorescence, silica nanoparticles, sandwich determination, ethylenediamine fluorescein thiocarbamyl (EDF), Schiff base, The covalent binding of analytes is barely used in wet chemical analysis because it is more time consuming than noncovalent one, and it often requires heating. However, some types of [...]

The main methods for the determination of local anesthetics are considered, and their advantages and disadvantages are discussed. After the systematization of published data, it was established that the greatest number of works were devoted to the determination of novocaine, lidocaine, and ultracaine; therefore, methods for their determination are considered separately. It was demonstrated that the extraction and sorption preconcentration of local anesthetics as ion associates with chromogenic organic reagents is promising. It was substantiated that the development of combined rapid and sensitive extraction-photometric, sorptionspectroscopic, and colorimetric methods for the determination of novocaine, lidocaine, and ultracaine with chromogenic organic reagents in different test materials is a problem of considerable current interest. Keywords: local anesthetic agents, novocaine, lidocaine, ultracaine, combined determination methods, GENERAL CHARACTERISTIC OF LOCAL ANESTHETIC AGENTS Local anesthetics (from the Greek anesthesis, insensibility: an-, without + aisthesis, feeling) are selective agents to be applied to peripheral nerve tissue in order [...]

The use of 1,2-dihydroxyanthraquinone-3-sulfonic acid sodium salt, Alizarin Red C (ARC), is considered in application to the sorption-spectrophotometry determination of organic bases novocaine and lidocaine, used as local anesthetics. The optimal conditions for the formation of all adsorbates are determined, and the equations depicting the relation between the chromaticity functions (CFs) and concentration of organic bases are found. As shown, ARC absorbs chemically on the surface of γ-[Al.sub.2][O.sub.3] as ions with the charge 2--with a predominantly vertical orientation. The calculated molar coefficients of sorbates' CFs are 200 times hugher than the ones for respective extracts. Based on the developed procedures, color scales for the rapid testing of analytes are developed. The potential use of the procedures elaborated is discussed. Keywords: sorption--spectrophotometry method, chromaticity measurements, local anesthetics, Alizarin Red C. DOI: 10.1134/S1061934812050085, In the investigation of equilibria in solutions, a wider abundance was acquired by optical techniques based on relations of absorbance to pH of solutions, as they deliver a maximum of [...]

The possibility has been considered for using 1,2-dihydroxyantraquinonone-3-sulfoacid (Alizarin Red S, ARS) as a colored agent for the determination of organic bases as of their ion associates. Spectrophotometric and colorimetric properties of the ion associates of cetyltrimethylammonium bromide and local anesthetics Novocaine and Lidocaine with ARS have been studied in aqueous solutions at pH 2-6; the optimal conditions for the formation of ion associates have been determined and the extraction mechanism has been revealed. Calibration curve equations have been obtained for the dependences of the absorbance of extracts and back extracts of organic bases in aqueous and organic phases, as well as the chromaticity functions (CF) of the ion associates on the concentration of the organic bases in aqueous and organic phases. Molar absorption coefficients and CF of the considered ion associates have been determined. The advantages of the color measurement over spectrophotometry for the determination of molar absorption coefficients and CF have been demonstrated. An application of the developed procedure has been proposed. DOI: 10.1134/S1061934810090054, Optical methods based on the absorbance dependence on the pH of the solutions are widely used for studies of equilibriums in solutions, since they provide maximum information on the behavior [...]

Acid-base, spectrophotometric, and colorimetric properties of 1,2-dihydroxyantraquinonone3-sulfoacid (Alizarin Red S, ARS) have been studied in aqueous solutions at pH 3--13. Equations of calibration curves have been obtained for the dependences of absorbance and colorimetric functions (CF) on the ARS concentration. Molar absorption coefficients and CF have been determined. Dissociation constants of ARS have been determined using a spectrophotometric technique in its computational and graphical versions at an ionic strength from 0.1 to 0.5. DOI: 10.1134/S1061934810050072, In the majority of the studies of equilibria in solutions, priority is given to optical techniques, which are based on the dependences of absorbance on the pH of solution [1]. [...]