Journal of Analytical Chemistry最新文献

This study introduces a dual-technique strategy for levofloxacin quantification, combining ultraviolet-visible spectrophotometry and a microfluidic paper-based analytical device (µPAD) to address the need for cost-effective, precise pharmaceutical quality control. Leveraging the reaction between levofloxacin and chlorophenol red, both methods form a colored complex (λ_max = 574 nm) via an acid-base interaction stabilized by electrostatic and hydrogen bonding. The spectrophotometric method demonstrates high sensitivity (limit of detection (LOD): 2.50 µg/mL, linear range: 5–100 µg/mL) with robust intra-day (relative standard deviation (RSD): 0.946–1.730%) and inter-day precision (RSD: 1.401–2.198%), alongside recovery rates of 91.5–102.6%. In contrast, the µPAD offers portability and rapid analysis (LOD: 10.119 µg/mL, linear range: 100–1000 µg/mL), achieving comparable accuracy (recovery: 90.6–96.1%) with minimal reagent consumption. Both techniques were validated according to the International Council for Harmonization guidelines, exhibiting negligible matrix interference in commercial formulations (Levolen, Levobact, Levofloxacin Vitapure). The spectrophotometric method excels in laboratory settings for precision, while the µPAD enables on-site testing, aligning with green chemistry principles. This dual approach bridges technological gaps, providing versatile tools to ensure accurate dosing, support antimicrobial stewardship, and enhance global pharmaceutical quality control.

The urine protein-to-creatinine (P/C) ratio is a rapid and accurate method for measuring proteinuria in the diagnosis of kidney diseases. A smartphone device enables rapid determination of creatinine and proteins in urine. A smartphone-based method was developed and validated for the detection of the P/C ratio in this study. Clinical urine samples were also analyzed and compared to the Beckman Coulter AU5800 results for correlation assessment. For proteinuria, the limit of blank (LOB) and limit of detection (LOD) were 4.23 and 8.8 mg/dL, respectively, with a lower limit of quantification (LOQ) of 9.2 mg/dL and a linear range from 9.2 to 122 mg/dL. The intra-batch precision coefficient of variation (CV) was 2.5%, and the inter-batch precision CV ranged from 3.0 to 3.3%. For creatinine, the LOB and LOD were 13.2 and 17.9 μmol/L, respectively, with a LOQ of 28 μmol/L and a linear range from 28 to 209.12 μmol/L. The intra-batch precision CV was between 2.7 and 2.8%, and the inter-batch precision CV was between 2.9 and 3.8%. The smartphone-based method for P/C detection is a reliable, cost-effective, and portable option for accurately measuring urinary protein and creatinine, suitable for remote diagnostics and home health checks.

Microplastic emissions to the environment increase every year. Over the past twenty years after the first publication on the study of microplastics, the problem of the global environmental pollution by synthetic materials has been confirmed, its toxicological effect has been proven at all levels of the organization of biosystems, including human health. Spectral, chromatographic, microscopic, and thermal methods of analysis are used to study microplastics. This review considers these groups of methods in the context of their application to the identification of microplastics and the determination of toxic substances associated with them.

The effect of the concentration of mercaptopropyl groups chemically attached to a silica surface in the range from 0.18 to 0.76 mmol/g on the formation and color intensity of Pd(II) complexes with the attached groups, as well as mixed-ligand complexes of palladium(II) and silver(I) with attached mercaptopropyl groups and dithizone is studied. It is shown that, with an increase in the concentration of the attached mercaptopropyl groups, the color intensity of sorbents containing an equal amount of the adsorbed palladium(II) increases. In the case of the formation of mixed-ligand complexes of palladium(II) and silver(I) with the attached groups and dithizone, with an increase in the surface concentration of the attached groups, the intensity of the sorbent color decreases. Procedures for the sorption–photometric determination of palladium(II) as complexes with the attached groups and palladium(II) and silver(I) as surface mixed-ligand complexes are developed. It is concluded that, to achieve low limits of detection of elements as their complexes with the attached groups by the sorption–photometric method, the concentration of the attached groups should be maximum, and to achieve low limits of detection of elements as their mixed-ligand complexes with the attached groups and dithizone, the concentration of the attached groups should be minimum.

A methodological gap in the study of environmental nanoparticles is largely due to their extremely low concentrations—typically around 0.01–0.1%—in ash, dust, or soil, which significantly complicates their extraction and quantification. This study demonstrates the efficiency of a novel sample preparation protocol for volcanic ash samples, involving sequential dispersion in 0.1 M NaCl and 2 mM Na₄P₂O₇, followed by nanoparticle extraction by flow field-flow fractionation in a rotating coiled column, using a 2 mM Na₄P₂O₇ solution as an eluent. Thise method ensures an increase in the mass of the extracted nanoparticles by one order of magnitude and enables the detection of elements such as Be, Cr, Co, Zn, Ag, Sb, Te, Ta, W, Tl, and Bi in ash-derived nanoparticles from various volcanoes in concentrations below the limits of detection by ICP–MS using deionized water as an eluent. In addition, the results of the procedure are not distorted by analytical artifacts, such as the formation of poorly soluble calcium phosphates during sample preparation. This approach provides a foundation for the systematic studies of ash-derived nanoparticles from a wide range of volcanic types, as well as of urban dust.

Sorption methods, including solid-phase extraction, are widely used in the determination of platinum-group metals (PGMs), which is confirmed by a permanently large number of publications. This review is devoted to the description of different types of sorbents developed for the preconcentration and selective recovery of PGMs and their use in the analysis of geological, natural, and technological samples. Trends in the design of materials and physical fields to intensify the processes of the solid-phase extraction of PGMs are discussed. The review considers publications mainly for 2010–2025.

The solid-phase extraction of ion pairs formed between acidic azo dyes—Sulfonazo and Congo Red—and papaverine (1-(3,4-dimethoxybenzyl)-6,7-dimethoxyisoquinoline) on polyurethane foams is studied as a function of pH, phase contact time, and component ratio. A procedure is developed for determining papaverine in pharmaceutical formulations based on its adsorption as ion pairs with azo dyes, followed by detection on the adsorbent surface using diffuse reflectance spectroscopy and colorimetry.

Due to its pharmacological and biological activity, bee venom is used in the production of various drugs and pharmaceutical forms, including ointments and creams. Melittin is the main component of bee venom, and its presence in a drug preparation is characteristic of the presence of bee venom as a constituent. An approach to the detection of this characteristic peptide component of bee venom in semisolid dosage forms, which involves recovery and preconcentration using solid-phase extraction followed by liquid chromatography with mass spectrometric detection, was proposed. The specificity of the detection procedure was validated, and the limit of detection was 0.1 μg/g.

Sensors are developed for the amperometric determination of the antibiotics Cefur and Ceftr in aqueous solutions. The sensor electrodes were coated with a molecularly imprinted polymer (MIP). To assess the selectivity and molecular recognition ability of the sensors, the imprinting factor and selectivity coefficient were determined. The imprinting factor reached 5.3 for MIP-Cefur and 5.1 for MIP-Ceftr. The results demonstrated that the MIPs exhibited higher selectivity and recognition capability for Cefur and Ceftr compared to non-imprinted polymers. The antibiotics were quantified in aqueous solutions using the calibration curve method. The experimentally found concentration ranges for Cefur and Ceftr were from 1.0 × 10^–5 to 0.1 g/L. The limits of detection were 3.5 × 10^–6 g/L for Cefur and 6.6 × 10^–6 g/L for Ceftr. MIP-modified sensors were tested in the determination of antibiotics in wastewaters. The findings confirmed the applicability of amperometric sensors based on molecularly imprinted polymers to the determination of Cefuroxime sodium and Ceftriaxone sodium in both model and real aqueous solutions.

A method is proposed for the extraction and preconcentration of six of the most common endocrine disruptors (dimethyl, diethyl, dibutyl phthalates; bisphenol A; and octyl- and nonylphenols) from river bottom sediments. The analytes are extracted by two-stage preconcentration. At the first stage, the analytes are extracted from an aqueous solution with an ionic liquid, 1-hexyl-3-methylimidazolium hexafluorophosphate in the presence of a surfactant (sodium dodecyl sulfate). The volumes of the extractant and surfactant solution (12 vol %) are 200 μL and 0.5 mL, respectively. Extraction duration is 2 min. At the second stage, magnetic dispersive solid-phase extraction with magnetic coals of plant origin modified with reversed phases of n-octyltrimethoxysilane and n-octadecyltrimethoxysilane is used. The recovery of analytes by liquid–liquid extraction is 91–99% and by magnetic solid-phase dispersive extraction, 89–99%. It is found that, during solid-phase dispersive extraction, the best conditions for the extraction of disruptors are achieved at pH 5.2–7.0, sorption duration of 5 min using a centrifuge (4000 rpm), and sorbent portion of 25 mg. The use of two-stage preconcentration in combination with gas chromatography–mass spectrometry ensures the determination of endocrine disruptors in bottom sediments at a level of 0.4–0.7 μg/kg.