Application of Chemometrics Approaches to Analysis of Mid-Infrared Spectra of Ibuprofen Diluted in Supercritical Carbon Dioxide

Near Infrared Spectroscopy As an Effective Way of Studying Hydrogen Bonding in a LiCl–H2O–CO2 Ternary Mixture

Abstract

The possibility of using near IR spectroscopy to analyze the effect isobaric heating has on hydrogen bonding in an aqueous solution of LiCl in equilibrium with supercritical carbon dioxide (a LiCl–H2O–scCO2 ternary mixture) is demonstrated in a wide range of electrolyte concentrations. It is shown that this approach is highly efficient when studying ion and molecular systems with different types of interparticle interactions. The use of near IR spectroscopy allows distinguishing spectral contributions from hydrogen bonded n-mers of bulk water and water molecules in the solvation shells of ions or in ion–water chains like those formed in solutions with extremely high electrolyte concentrations that do not contain bulk water. It is shown for the studied ternary mixture that raising the concentration of electrolyte completely neutralizes the destructive effect of carbon dioxide on the formation of a hydrogen bonded structure of water. The latter is stabilized under the influence of an ion field, which also substantially weakens the temperature effect.

TiO2 nanoparticles and C-Nanofibers modified magnetic Fe3O4 nanospheres (TiO2@Fe3O4@C-NF): A multifunctional hybrid material for magnetic solid-phase extraction of ibuprofen and photocatalytic degradation of drug molecules and azo dye

Accurate sensitive analysis of drug ingredient substances in biological, pharmaceutical and environmental samples and removal of drug ingredient substances in environmental samples owngreat importance for sustaining viability. The realization of these processes using a single material offers significant advantages in terms of cost, time and ease of use. In this study, TiO₂ nanoparticles and C-Nanofibers modified magnetic Fe₃O₄ nanospheres (TiO₂@Fe₃O₄@C-NFs) synthesized as a multifunctional material employing a simple hydrothermal synthesis method. This innovative material was exploited in the magnetic solid-phase extraction (MSPE) method for the preconcentration of ibuprofen and photocatalytic degradation of antibiotics, non-steroidal anti-inflammatory drugs (NSAIDs), and azo dye. To our knowledge, no studies have been previously conducted using the same material as magnetic solid-phase extraction adsorbent and magnetically separable photocatalyst. The characterization of TiO₂@Fe₃O₄@C-NFs was carried out by XRD, FE-SEM, EDX and Raman techniques. The main analytical parameters affecting MSPE performance of ibuprofen such as pH, sorbent amount eluent type and volume and sample volume were optimized. The optimum values of the method were determined at the following parameters: pH 4.0, adsorbent amount 150 mg and eluent 2 mL of acetone. Ibuprofen analysis after MSPE was carried out using a high-performance liquid chromatography diode array detection system (HPLC-DAD). The photocatalytic degradation efficiencies of TiO₂@Fe₃O₄@C-NF hybrid material for probe-analytes reached 80-100% and the complete degradation attained within the range of 8-125 min under UV irradiation. Simple preparation, practical isolation from solutions, high efficiency, reproducibility, and sustainability are the main advantages of the TiO₂@Fe₃O₄@C-NFs for MSPE and photocatalytic degradation applications.