No abstract

Salicylic acid and its derivatives are widely used in medicine and pharmacy as antipyretic, antirheumatic, anti-inflammatory and analgesic drugs for external and internal use. The development of methods for the quantitation of salicylic acid in multicomponent samples using selective methods of sample preparation is an important problem in quality drug control. The aim of the study was to obtain sorbents based on ethyl cellulose for solid-phase extraction of salicylic acid from aqueous solutions. As a result of the study, a method for obtaining a sorbent for solid-phase salicylic acid from aqueous solutions was proposed. The IR spectroscopy of the obtained sorbent samples did not establish significant structural differences between ethylcellulose and the obtained sorbents. Optimal concentrations of ethylcellulose and salicylic acid solutions in the reaction mixture for obtaining the sorbent with a maximum value of sorption capacity of 93.5 g/g of sorbent were revealed. The method for the quantitation of salicylic acid from aqueous solutions with the use of the obtained sorbent was proposed. Metrological estimation of salicylic acid quantitation with the help of the obtained sorbent for solid-phase extraction was carried out.

Aim to obtain sorbents based on ethylcellulose for solid-phase extraction of benzoic acid from aqueous solutions. Material and methods. To create the sorbents for solid-phase extraction, we used the following reagents: ethyl cellulose, copper sulfate pentahydrate, sodium hydroxide, benzoic acid, purified water, ethyl alcohol 95%. The samples of ethyl cellulose-based sorbents were studied by Fourier transform IR spectrometry on an Agilent Cary 630 FTIR spectrometer. The Agilent Microlab PC Expert software was used for registration and primary processing of IR spectra, and for statistical analysis. The capacity of sorbents for solid-phase extraction was evaluated in a dynamic mode. The microstructure of the samples was studied by field emission scanning electron microscopy (FE-SEM) on a Hitachi SU8000 electron microscope. The specific surface area of the synthesized sorbents was measured by low-temperature nitrogen porometry using the Brunauer Emmett Teller approximation, on the Autosorb 1 device, using the Quantachrome AS1Win software, according to a well-known technique. Results. А method was proposed for obtaining a sorbent for solid-phase extraction of benzoic acid from aqueous solutions. The IR-spectrometry did not reveal significant differences between ethylcellulose samples and the obtained sorbent samples. The optimal concentrations of ethylcellulose and benzoic acid in the reaction mixture were determined to create a sorbent with a maximum capacity of 19.2 g/g. The differences in the morphological structure of the surface of ethylcellulose matrix and obtained sorbents were described. The specific surface area of ethylcellulose sorbent with a maximum capacity for benzoic acid was 14.10 cm2/g.