International Journal of Analytical Chemistry最新文献

In this study, the establishment and validation of a stable reversed-phase high-performance liquid chromatography (RP-HPLC) method for the concomitant estimation of the two drugs in dosage forms are presented. Method optimization was achieved by response surface methodology (RSM) using Design Expert Software 13, taking into account the special physicochemical characteristics of metoclopramide (MET) (a moderately polar molecule, pKa 9.5) and camylofin (CAM) (a less polar, hydrophobic molecule, pKa 8.7). Chromatographic resolution was achieved on a phenyl-hexyl column under isocratic mobile phase mode in which methanol and 20 mM ammonium acetate buffer (pH 3.5) were used to provide maximum analyte interaction and resolution. The method was found to have good linearity for both analytes (R ² > 0.999) over the concentration ranges studied. Limits of detection were 0.23 and 0.15 μg/mL for MET and CAM, respectively, and corresponding limits of quantification were 0.35 and 0.42 μg/mL, respectively. Recovery tests gave high precision values of 98.2%-101.5%, while intra- and inter-day precision in relative standard deviation (RSD) was below 2%. The method was effectively applied for the analysis of commercial tablet formulations, confirming its reliability and suitability for routine quality control and regulatory analyses. Overall, the validated RP-HPLC method provides a sensitive, accurate, and efficient means of simultaneous determination of MET and CAM in pharmaceutical dosage forms.

The occurrence of crystallization plugging in the tunnel drainage system will lead to cracking and leakage of the tunnel lining. Therefore, it is very important to take effective measures to prevent the blockage of the crystallization pipe of the tunnel drainage system and ensure the safety and stability of the lining structure during the operation of the tunnel. In this study, we conducted field surveys and laboratory tests to analyze the relationship between the crystals in the Yijun tunnel blind pipeline and the concentration of various ions in the groundwater. X-ray diffraction (XRD) analysis confirmed that the main component of the crystalline sediment was calcium carbonate. The formation mechanism of crystallization was explored by using the environmental water chemical equilibrium software, Visual MINTEQ 3.1. Considering that the preparation of cleaning agent has less corrosive effect on tunnel concrete materials, the cleaning efficiency test of various acid cleaning agents on tunnel crystals was carried out to determine the optimal concentration of cleaning solution. Finally, it is determined that the mixture of formic acid: citric acid: corrosion inhibitor: surfactant: water = 1:0.5: 0.5:0.5: 5 is used as the cleaning agent of tunnel blind pipe. The experimental results show that the cleaning agent has a 92.4% CaCO₃ dissolution rate, and the pH is controllable (4.7-7.9), which meets the environmental protection standards, and has little damage to the concrete (strength loss of 3.4 Mega Pascal, control group 6.2 Mega Pascal).

The demand for cobalt-based alloys has been steadily increasing due to advancements in industrial and cutting-edge technologies, particularly in metallurgy, where cobalt plays a crucial role in high-performance superalloys, battery production, and corrosion-resistant materials. Consequently, the concentration of cobalt ions in wastewater and environmental samples has exceeded permissible levels, raising significant ecological concerns. This study presents the development of an efficient method for the determination of cobalt(II) ions using a silver/mercury film working electrode (Hg(Ag)FE) modified with the organic dye ortho-nitrosophenol (o-NF) through cyclic voltammetry (CV). Optimization of the experimental conditions revealed that an acetate buffer (0.1 M, pH 5.1) served as the supporting electrolyte, with an accumulation time of 10 s and a concentration of 2.0 μM o-nitrosophenol. The preconcentration conditions were adjusted to enhance the sensitivity and selectivity for cobalt(II) ion detection. The method exhibited a linear relationship in the concentration range of 0.040-0.160 μM (R ² = 0.9863), with a limit of detection (LOD) of 0.010 μM and a limit of quantification (LOQ) of 0.034 μM for Co(II) ions. The proposed method was successfully applied to the analysis of water samples from the Aydar-Arnasoy Reservoir, and the accuracy of the results was statistically validated using Student's t-test. These findings demonstrate the potential of the developed method as an effective tool for environmental monitoring and the determination of cobalt ions in ecological protection initiatives.

[This corrects the article DOI: 10.1155/2024/3374034.].

A significant improvement in sustainability and efficiency is achievable through green and white chemistry. As part of this study, sustainability assessment tools were used to assess the environmental impact and practicality of an innovative, straightforward RP-UPLC method to analyze cyclopentolate (CLO) and its organic impurities simultaneously in pure and ophthalmic solutions at the same time. An optimization strategy based on Box-Behnken design was employed to minimize experimental runs while optimizing chromatographic conditions. Using this design, four critical variables were evaluated comprehensively-ethanol percentage in the mobile phase, pH, column temperature, and flow rate-on chromatographic responses such as retention time, resolution between CLO and impurity, and theoretical plate count. As a result of desirable and overlay plots, an optimal condition was selected: 65:25, v/v, ethanol and buffer, pH 4.25, 0.3 mL/min flow rate, and 4°C and 25°C sample and column oven temperatures, respectively, and the main peak retained for a little more than 3 min. The calibration curves for CLO and impurities at concentrations from 5 to 50 μg/mL and 1 to 20 μg/mL showed a correlation value of 0.9998. Recoveries are ±15% of the actual amounts, which is acceptable. RP-UPLC has been extensively designed for the coincidental estimation of anticholinergic drugs and their impurities. A combination of white and green tools was used to assess the method's environmental impact. ICH guidelines have been followed to validate the suggested strategy. This approach offers a reliable, fast, and eco-friendly solution for routine pharmaceutical quality control of anticholinergic agents.

This study examines the flue gas emissions originated from various fuel types used in the textile industries of Faisalabad, Pakistan, and their compliance with the Punjab Environmental Quality Standards (PEQS), Pakistan. Data from 109 textile factories revealed significant emission variations based on fuel types. Natural gas was identified as an eco-friendly fuel, with emissions far below the PEQS limits (CO: 334.8 mg/Nm³, SO₂: 175 mg/Nm³, NO_x: 692 mg/Nm³). Moderate fuels such as corncob, wood, and coal exhibited emissions that slightly exceeded PEQS limits but could be mitigated by adopting advanced emission control systems. In contrast, cloth waste exhibited the highest emissions, significantly exceeding PEQS thresholds (CO: 2091.4 mg/Nm³, SO₂: 2978 mg/Nm³, NO_x: 487.5 mg/Nm³), followed by mixed fuels such as wood + cloth waste. Smoke opacity and flue gas concentrations were used to classify the fuels into eco-friendly, moderate, and acute impact categories. Findings underscore the urgent need for the adoption of cleaner fuels, enhanced emission control systems, and stricter regulatory enforcement to mitigate environmental and health impacts in Pakistan's textile sector. This research provides a framework for transitioning to sustainable industrial practices, aligning with global climate action and sustainable development goals (SDGs).

The intravenous anesthetic propofol is frequently used for the induction and maintenance of general anesthesia. Propofol has, however, a potential for abuse, and it has been involved in suicide deaths particularly among medical personnel. The long-term stability of propofol concentrations in human plasma samples when stored under normal laboratory conditions over several years might be important for forensic toxicology. The present study investigated the long-term stability of propofol after storage at -20°C for eight years. For this purpose, 67 plasma samples from five patients, who had undergone a former clinical trial, were re-analyzed. Plasma samples were extracted using protein precipitation. Propofol plasma concentrations were determined by ultra-performance liquid chromatography (UPLC) with gradient elution, followed by tandem mass spectrometry with electrospray ionization. Deuterium-labeled propofol was used as an internal standard. The assay was linear in the range of 50-10,000 ng/mL with a limit of detection of 0.5 ng/mL and a lower limit of quantification of 50 ng/mL, respectively. Accuracy and precision were high with intra- and interassay errors within ±5%. The median relative deviation between the measurements in 2023 and 2015 was -7.0% (interquartile range: -19.7% and 5.3%). Therefore, propofol concentrations in human plasma can be considered relatively stable in samples frozen at -20°C over eight years, and plasma samples stored under these conditions might be used for forensic purposes. Trial Registration: ClinicalTrials.gov identifier: NCT02199067.

Based on the establishment and validation of a UPLC-MS/MS method for detecting glipizide in beagle plasma, the herb-drug interaction (HDI) between berberine and glipizide was studied. After gradient elution separation of glipizide and internal standard, multiple reaction monitoring was used for detection in positive ion mode. The ion reactions used for quantitative analysis were glipizide m/z 446.0 ⟶ 321.0 and IS m/z 307.1 ⟶ 220.0. Six beagle dogs were treated with glipizide alone and berberine intervention, and the pharmacokinetic changes of glipizide were compared. The UPLC-MS/MS method has good linearity and the advantages of being green, simple, sensitive, and fast. After continuous administration of berberine to beagle dogs for 7 days, the pharmacokinetic process of glipizide changed with C _max, AUC_(0-t) and AUC_(0-∞) increasing, t_1/2 prolonging, and CL and Vd decreasing. When using combination therapy, attention should be paid to possible HDI.

Artesunate-amodiaquine (ARS-AQ) is a first-line antimalarial treatment recommended by the World Health Organization. AQ is the long acting partner drug in this combination, and therapeutic success is correlated with the terminal exposure to AQ. Dried blood spot (DBS) sampling for AQ is a convenient and minimally invasive technique, especially suitable for clinical studies in resource limited settings and pediatric studies. Our primary aim was to develop and validate a bioanalytical method for quantification of AQ and its active metabolite in capillary blood applied onto filter paper as a DBS sample. The separation was achieved using a reverse phase column (Zorbax SB-CN 50 × 4.6 mm, I.D. 3.5 μm) and a mobile phase consisting of acetonitrile:ammonium formate 20 mM with 0.5% formic acid (15:85, v/v). A 50 μL DBS was punctured with five 3.2 mm punches from the filter paper, and the punches collected correspond to approximately 15 μL of dried blood. The blood was then extracted using a mixture of 0.5% formic acid in water:acetonitrile (50:50, v/v), along with stable isotope-labeled internal standards (AQ-D10 and desethylamodiaquine [DAQ]-D5). Mass spectrometry was used for quantification over the range of 2.03-459 ng/mL for AQ and 3.13-1570 ng/mL for DAQ. The validation of the method was carried out in compliance with regulatory requirements. The intra- and interbatch precisions were below 15% and passed all validation acceptance criteria. No carryover and no matrix effects were detected. Normalized matrix factors (analyte/internal standard) ranged from 0.96 to 1.03 for all analytes, hence no matrix effects. AQ and DAQ were stable in all conditions evaluated. Long-term stability in DBS samples was demonstrated for up to 10 years when stored at -80°C and for 15 months when stored at room temperature. The developed method was demonstrated to be reliable and accurate. This assay may be particularly useful in the context of resource limited settings and in pediatric field studies.

A novel and simple study outlines the advancement of a straightforward and precise spectrophotometric technique for the determination of Cd (II) ions. This method offers a notable benefit as it is a straightforward procedure that does not require additional purification or concentration of the solvent. The concentration of Cd (II) ions was determined in the presence of bis(indoline-2, 3-dione) thiosemicarbazone (L) at a pH of 12 using Briton-Robinson Buffer. The concentration range for Cd (II) ions in the method follows Beer's law and is between (1.8-17.8) × 10^-5 mol L^-1. The limit of detection is 0.245 μg mL^-1(2.2 μmol L^-1) and the limit of quantification is 0.817 μg mL^-1 (7.3 μmol L^-1). The molar ratio between L and Cd (II) ions was 1:2, ensuring the development of a metal complex. The applied method offers numerous benefits, including its simplicity, affordability, convenience of use, quick detection, minimal use of ligands, and high sensitivity. The sensitivity of the analytical approach was verified by carefully selecting appropriate experimental conditions. Additional insights into the composition and arrangement of the complex produced in a solution containing Cd (II) ions and the ligand (L) have been obtained by isolating and studying the solid complex L-Cd. The solid complex, L-Cd, was determined using analytical methods including elemental analysis, UV-Vis spectra, spectral mass, and thermal analysis.