Journal of Analytical Chemistry最新文献

A simple and cost-effective analytical approach is proposed based on a gas diffusion-flow injection procedure for determining ammonia in human saliva. The proposed procedure utilizes purple sweet potato extract as an acceptor reagent. The principle of determining ammonia is based on the total ammonia in saliva, which is transformed to ammonia gas in the NaOH donor stream, which diffuses through the gas diffusion membrane to the acceptor stream containing purple sweet potato extract. The presence of ammonia changed the color of the extract, which was detected at a wavelength of 604 nm, with absorbance proportional to the ammonia concentration. Optimization of standard parameters produced optimal results under 1.5 M NaOH, 10% extract, and 50 cm mixing coil with 300 μL sample volume. The results of the procedure were selective against phosphate, magnesium, and calcium, with less than a 5% bias value. The result was valid when applied to human saliva and supported by a 101–103% recovery. The proposed gas diffusion-flow injection procedure offers on-site assay and green chemical analysis with relatively high throughput.

Electrodes modified with gold particles, multi-walled carbon nanotubes, an ionic liquid based on 1-butyl-3-methylimidazolium hexafluorophosphate, and a composite derived from these materials have been developed for the voltammetric determination of sulfamethazine, sulfacetamide, and sulfathiazole. Cyclic voltammetry reveals that modifying the surface of a glassy carbon electrode with gold particles, a composite of carbon nanotubes, and an ionic liquid increases its effective surface area. Electrochemical impedance data indicate that the rate of electron transfer on the modified electrodes surpasses that on the unmodified ones. The composite electrode containing gold particles, carbon nanotubes, and the ionic liquid, exhibited the best performance, was utilized for the amperometric determination of sulfonamides in a batch-injection analysis system. Optimal parameters for the determination of sulfonamides in the batch-injection setup were found. The relationship between the analytical signal and the concentration of the compounds on the logarithmic coordinates is linear, ranging from 1 × 10^–8 to 5 × 10^–3 M for sulfamethazine and sulfacetamide, and from 1 × 10^–7 to 5 × 10^–3 M for sulfathiazole. The proposed method for determining sulfonamides has been tested in ananalysis of pharmaceutical preparations.

The efficient extraction of tianeptine from environmental matrices has been a matter of concern issue due to the amphiphilic ionic organic substance property of tianeptine. A magnesium-iron layered double hydroxide (Mg/Fe-LDH) was successfully synthesized using hydrothermal synthesis and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy techniques. The as-prepared nanocomposite was used as an effective adsorbent to extract tianeptine from water samples via a dispersive solid-phase extraction (DSPE) procedure before high-performance liquid chromatography-ultraviolet detection (HPLC-UV). Experimental parameters affecting extraction efficiency, such as agitation type, pH, absorbent amount, elution solvent type, and absorption/elution time, were studied and optimized. The developed tianeptine analysis method, based on adsorption-release extraction using Mg/Fe-LDH and detection by HPLC-UV, exhibited a wide quantitative linear range of 10 to 1000 μg/L (r² = 0.9986, p = 2.49 × 10^–14) by plotting chromatography peak height versus tianeptine concentration. The limits of detection and quantification were 4.6 and 15 μg/L, respectively. The developed tianeptine analysis method was applied to analyze tianeptine spiked in water samples. An ideal recovery range of 94.1 to 103.5%, with a narrow relative standard deviation of 1.63–4.34%, was obtained. The proposed analysis method, which combined Mg/Fe-LDH-based DSPE with HPLC-UV detection, was reliable for determining tianeptine in environmental water samples.

N,O-hybrid donor ligands are promising compounds for the isolation and separation of actinides and lanthanides from process solutions of spent nuclear fuel reprocessing. Newly synthesized N,O-hybrid donor ligands – derivatives of 2,6-pyridinedicarboxylic acid were studied as extractants and membrane components for potentiometric sensors. The extraction ability of solutions of these compounds in meta-nitrobenzotrifluoride towards d- and f-elements from nitric and perchloric acid solutions was investigated. It was shown that the replacement of amide groups with ester groups reduces the extraction ability of the ligands. Switching from nitric acid to perchloric acid gives a dramatic increase in extraction capacity due to the perchlorate effect. Also, a significant increase in extraction capacity is observed when chlorinated cobalt dicarbolide is added to the organic phase: the highest distribution coefficient is observed at a 1 : 1 ratio of extractant and additive concentrations. Potentiometric membrane sensors based on the new ligands showed significant sensitivity to Cd²⁺. Correlations between extraction and sensing behavior of new ligands were studied.

Some methods of X-ray spectral analysis used by Russian researchers to determine the elemental composition of medicinal plants are considered. The review focuses on the articles published in Russian journals over the past 20 years. Researchers utilize wavelength dispersive X-ray fluorescence (WDXRF), energy dispersive XRF (EDXRF), synchrotron radiation XRF (SRXRF), and total reflection XRF (TXRF) spectrometry; electron probe microanalysis, and scanning electron microscopy to analyze both macro- and microelement contents in medicinal plants. The simultaneous determination of macro- and microelements, coupled with nondestructive sample preparation, makes XRF spectrometry an attractive method for identifying and monitoring the chemical composition of plants, especially those employed in medical practice. Most published studies provide comprehensive information on sample preparation and measurement procedures, present metrological evaluations, and discuss the results obtained. However, some publications lack essential methodological details, and misprints in the presented analytical data occur.

Beta-blockers (β-blockers) are broadly used to manage cardiac arrhythmia, which could increase in the upcoming years due to the aging population and the increase in the number of patients with cardiac burden. In the current work, a simple, sensitive, and reliable simultaneous determination of five β-blockers (acebutolol, pindolol, atenolol, nadolol, and oxprenolol) was accomplished by ionic liquid (IL)-modified reversed-phase liquid chromatography with ultraviolet detection. The chromatographic separation was achieved on a ZORBAX^® SB-C18 column using a hybrid mobile phase consisting of 50 µg/mL 1-butyl-3-methylimidazolium chloride dissolved in 0.02 mol/L phosphate buffer (pH 3.5) and acetonitrile (70 : 30, v/v). The chromatographic measurements were performed by isocratic elution at a 1.0 mL/min flow rate, 230 nm wavelength, and 25°C column temperature. The current method was applied to human plasma matrices by direct injection of samples with a short analysis time of 12 min. Good linearity was achieved in the range of 3–500 ng/L for atenolol, acebutolol, and pindolol, 7–500 ng/L for acebutolol, and 10–500 ng/L for oxprenolol with a 0.999 coefficient of determination. The limit of detection/limit of quantification values were 1.04/3.00, 2.75/7.00, 1.03/3.00, 1.05/3.00, and 3.47/10.00 ng/L for atenolol, nadolol, acebutolol, pindolol, and oxprenolol, respectively. Results of intra-day and inter-day precision were found to be less than 2%. The sensitivity enhancement factors of analytes due to the addition of IL ranged between 9- and 41-fold higher than that achieved in the absence of IL. Therefore, the proposed method could be used as a simple and sensitive analytical method for routine clinical analysis of β-blockers with the presence of a small amount of IL.

A new, simple, rapid, accurate, and precise high-performance thin-layer chromatography (HPTLC) method has been developed for the estimation of topiroxostat in bulk and tablet dosage form. In this method, aluminum plates with precoated silica gel 60 F₂₅₄ were used as the stationary phase. The mobile phase consisted of ethyl acetate, toluene, methanol, and glacial acetic acid (5 : 4 : 1 : 0.1, v/v/v). The calibration plot showed good linearity in the range of 40–240 ng/spot with a coefficient of regression, r² of 0.994, with respect to peak area. Ishikawa (fishbone) diagram and failure mode effect analysis were used as risk assessment tools. The saturation time, band length, and volume of methanol were determined as critical method parameters and extensively optimized employing Box-Behnken design, with a focus on the retardation factor value as the critical analytical attribute. The method was validated according to the International Conference on Harmonization guideline Q2 (R1). The limits of detection and quantitation were 1.45 and 4.41, respectively. The percentage recovery was found to be 99.59%. The degradation study was carried out in acidic, basic, oxidative, neutral, dry heat, and photolytic conditions. Therefore, it was concluded that the developed HPTLC method can be applied for the identification and quantitative determination of topiroxostat in bulk and tablet dosage form.

Asteracantha longifolia (L.) Nees, a small, spiny weed, has effective antitumor, hypoglycemic, aphrodisiac, antibacterial, free radical scavenging, lipid peroxidation, and hepatoprotective properties. It is an essential herb in many traditional and herbal medicines. Active phytoconstituents such as betulin, lupeol, stigmasterol, and β-sitosterol are reported to accord the herb importance as a medicinal plant in modern and traditional medicine. With the implementation of recent regulatory requirements, monitoring raw materials' quality attributes and quantifying the essential phytoconstituents is crucial. Therefore, this article discusses the first-time application of the quality by design (QbD) approach for Asteracantha longifolia (L.) Nees in developing a sensitive, rapid analytical method for the simultaneous quantitation of four bioactive phytoconstituents using high-performance liquid chromatography equipped with photodiode array detector, and validated fully in line with the guidelines by ICH. The QbD approach is an application of risk assessment and determines a design space where the developed analytical method performs at its best compared to traditional methods.

A method is proposed for the nondestructive control of azithromycin and clarithromycin active substances in tableted pharmaceuticals without opening blister packs by measuring the intensity of the diffuse reflection of IR radiation. Two methods are used: near-IR Fourier-transform spectrometry and colorimetry using a smartphone and a 3D-printed device. The data array (IR diffuse-reflection spectra and digital values of colorimetric channels) were processed by principal component analysis, hierarchical cluster analysis, and partial least squares regression using the TQ Analyst, PhotoMetrix PRO^® software. The use of chemometric algorithms for the determination of the concentration of active substances and the identification of the producer of the studied pharmaceuticals was considered. Methods of IR spectrometry and colorimetry have shown equally precise results in the identification of the producer of pharmaceuticals and the determination of the concentration of active substances in tablets without opening blister packs.

Polyvinylpyrrolidone (PVP) is available in a range of molecular weights and related viscosities that can be selected according to the desired application properties. A simple, accurate, and robust reversed-phase liquid chromatography method has been developed and subsequently validated for the estimation of polyvinylpyrrolidone K-90 in adhesive formulations. Separation and maximum response of the peak were obtained at UV a wavelength of 200 nm on a Zorbax Eclipse XDB C18 column. The limit of detection and limit of quantification of PVP were found to be 16.0 and 50.0 mg/L, respectively. The calibration curve showed good linearity over the concentration range of 50.0 to 1000.0 mg/L, with a correlation coefficient of 0.999. The proposed method was validated for specificity, linearity, accuracy, precision, robustness, and ruggedness, and successfully applied for the determination of PVP in glue samples.