International Journal of Analytical Chemistry最新文献

This study developed and comprehensively validated an optimized analytical method based on secondary thermal desorption-gas chromatography (STD-GC) for the simultaneous determination of eight key benzene homologs in ambient and indoor air of residential areas. Compared to solvent desorption and single-stage thermal desorption, STD demonstrates superior desorption efficiency, reduced matrix interference, fully automated rapid operation, complete analyte transfer, thereby eliminating analyte losses while enhancing analytical accuracy and sensitivity, and solvent-free ensuring friendly to human and the environment. Aiming at the characteristics of target compounds and complex environmental matrices (e.g., humidity, coexisting interferents), sampling parameters, thermal desorption conditions, and gas chromatographic separation conditions were systematically optimized, with particular emphasis on ensuring baseline separation of xylene isomers. The method demonstrated linearity over 10-1000 ng with correlation coefficients (R ²) > 0.992. The spiked recoveries of the method ranged between 90.5% and 117.3%, with relative standard deviations ranging between 0.8% and 9.2%, the detection limits ranged from 50 to 120 ng/m³, and the lower limits of quantitation ranged from 20 to 480 ng/m³. This study established a standardized and highly reliable analytical workflow, addressing the issues of parameter inconsistency and insufficient validation in existing methods when applied to paired residential-indoor air studies. Using this method, ambient and indoor air samples were synchronously collected and analyzed in residential areas. Results demonstrated significant correlations between indoor and outdoor concentrations of benzene homologs. This study also provides a methodological foundation and practical guidance for accurate assessment of residents' exposure to benzene homologs.

Sweat is an alternative biological fluid to plasma, urine, hair, and saliva, and it is promising for various pharmaceutical research types. Excessive sweating is one of the symptoms of cystic fibrosis, a hereditary disease. In this study, an easy, simple, applicable, and economical HPLC method was proposed for sweat analysis of the lumacaftor/ivacaftor combination used in the treatment of the disease. The solvent for the method was selected using the Green Solvent Selection Tool (GSST). The mobile phase was gradient elution mode and contained a mixture of 0.1% formic acid in acetonitrile (v/v) and 0.1% formic acid in water (v/v). Analytes were detected at a wavelength of 220 nm. LOD values for LUMA and IVA are 3.16 and 0.92 μg/mL, respectively. The linearity range was 60-150 μg/mL for both analytes, and matrix-matched calibration was performed. The greenness was evaluated with AGREE and ComplexGAPI, the whiteness with the red-green-blue 12 (RGB 12) algorithm, and the blueness with the Blue Applicability Degree Index (BAGI). The AGREE score of the method was calculated as 0.72, the BAGI score as 87.5, and the RGB 12 algorithm as 88.3. As a result, the method was presented to researchers as a sustainable, green, and efficient method.

This study centered on creating and validating a UPLC-MS/MS assay that is both reliable and simple, making it suitable for measuring peiminine levels in the plasma of beagle dogs. The established method was then employed with the ultimate goal of elucidating the pharmacokinetic behavior of the compound. The Acquity UPLC BEH C18 chromatographic column was used for separating peiminine and camptothecin (internal standard, ISTD). A binary mobile phase consisting of acetonitrile and 0.1% formic acid in water was used for gradient elution at 0.4 mL/min. In the multireaction monitoring mode, peiminine and a triple quadrupole mass spectrometer with an electrospray ionization source were utilized to monitor peiminine and the ISTD, and detection was performed by monitoring the following transitions: m/z 430.28 ⟶ 412.25 for peiminine and m/z 349.03 ⟶ 305.09 for the ISTD. Results indicated that the accuracy was around 100%, with both interday precision and intraday (RSD) being less than 10.37%. Additionally, a linear response for peiminine was validated over the range of 1-200 ng/mL, with the LLOQ established at 1 ng/mL. In summary, this study perfectly combined the ultrahigh chromatographic separation ability with the ultrahigh sensitivity, selectivity, and structural analysis ability of mass spectrometry, achieving rapid (2 min), accurate, and ultrasensitive (LLOQ 1 ng/mL) analysis of peiminine in samples. Using the developed method, the pharmacokinetic profile of peiminine was successfully characterized in beagle dogs following oral administration.

Natural gas (NG), primarily composed of methane, is colorless and odorless, thus necessitating odorization to enable leak detection and accident prevention. Precise monitoring of odorants is critical to meet safety standards while preventing excessive dosing. This study introduces a real-time gas chromatography system integrating gas chromatography and photoionization detection for the real-time, online odorant analysis in gas pipelines. This system effectively isolates tetrahydrothiophene (THT) and sulfur-free odorants from NG, enabling accurate concentration quantification. It achieves THT detection within 2∼150 mg/m³, with a relative standard deviation (RSD) of less than 1.5% and maximum deviation of less than 3 mg/m³. Additionally, this system exhibits good field applicability. When combined with a cloud-based warning platform, it can achieve monitoring, warning, and self-optimization of odorant concentration. This study demonstrates the reliability of this system for NG odorant monitoring, providing a robust solution for pipeline safety management and regulatory compliance, while offering a new approach for NG safety testing.

With the advancement of multiomics technologies and cohort study designs, integrative omics research is increasingly applied to human health and nutrition. However, optimal storage and preprocessing of labile biological samples, particularly feces, remain challenging. In this study, we systematically evaluated three normalization methods-wet weight, dry weight, and protein quantification-for quantitative metabolomic profiling of fecal samples, using 41 metabolites. Fresh fecal samples from three healthy individuals showed high reproducibility, with 24 metabolites exhibiting a coefficient of variation (CV) below 30 for both wet and dry weight normalization. Fecal samples from 20 obese patients collected using the OMNIgene·GUT kit demonstrated improved reproducibility with wet weight normalization (20 metabolites, CV < 30) and protein quantification normalization (19 metabolites, CV < 30), whereas dry weight normalization yielded no metabolites meeting the CV < 30 criterion. Direct analysis of the kit solution without a drying step further enhanced chromatographic clarity, highlighting practical considerations for large-scale studies. Overall, wet weight normalization consistently minimized variation across sample types, providing a robust and standardized framework for fecal metabolite profiling. These findings demonstrate that the OMNIgene·GUT kit is compatible with broad-spectrum metabolomic analyses and support its integration into multiomics workflows. By establishing reproducible normalization protocols, this study provides the foundation for accurate, comparable, and scalable fecal metabolomics in both clinical and nutritional research settings.

A current problem in analytical chemistry is to match the uncertainty of several independent sample replicates with the measurement uncertainty associated with first-order models. According to contemporary guidelines, calibration lines for method validations should be prepared with few standards, frequently without any blanks. These suggestions weaken the validity of the statistics, which are meant to address truth and accuracy rather than precision. As was previously shown when looking at the pooled calibration (PoPC) paradigm for method validation, excellent precision does not imply good accuracy. A novel technique known as combinatorial regression (CR) was created to estimate slopes, intercepts, and standard deviations to reduce disagreements regarding the computation of measurement uncertainty in accordance with the calibration line. The related standard deviations of several replicates were discovered to be too large to be applied to uncertainty. Concurrently, the idea of employing the numerical values of concentration residuals as promising estimates of measurement uncertainty arose from the fact that the standard deviations of the IUPAC equations are too small to be used in the computation of uncertainties. High-resolution continuous-source flame atomic absorption spectrometry (HR-CR FAAS), which has been demonstrated to produce inconsistent findings for the analysis of elements Na, Mg, and Ni, was used to evaluate the CR method on the determination of copper. The CR provided coefficients of variations (CVs) that rose with concentrations and number of replicates, favoring analyzing low concentrations in contrast to the IUPAC equations.

This research mainly focused on developing and validating the ultraperformance liquid chromatography photodiode array (UPLC-PDA) method to analyze 4-oxo-2-nonenal (4-ONE) in fully cooked meat products. The UPLC-PDA method developed has advantages such as sensitivity, excellent resolution, and fast separation through chromatography. To ensure its reliability and accuracy, the method underwent validation processes for linearity, precision, accuracy, robustness, and limit of detection (LOD) and quantification (LOQ). The results demonstrated a linear relationship between concentration and response within the 0.0032-10 ng/mL range with a correlation coefficient of R ² ≥ 0.9993. The method also exhibited precision with relative standard deviations (RSDs) below 2% for both intraday and interday analyses. Moreover, recovery studies confirmed the method's accuracy, with percent recoveries ranging from 97.16% to 105.9%. Furthermore, the results for LOD and LOQ were 0.03 and 0.091 ng/mL, respectively. Lastly, it was concluded that the developed method remains reliable under certain conditions by varying parameters such as the flow rate, mobile phase composition, and detection wavelength in robustness evaluations. This developed UPLC-PDA technique offers a reliable and effective means of identifying and measuring 4-ONE in cooked meat. It plays a role in ensuring food safety and addressing health issues associated with its consumption.

This study was carried out to assess the health hazards associated with the amount of the heavy metal lead (Pb), which is one of them, and samples of chromium (Cr) and cadmium (Cd) of dried fruits sold in Iraqi marketplaces. We gathered and used atomic absorption spectrometry (AAS) to assess 15 different samples of dried fruits that were imported from Iran. The average metal concentrations were as follows: (Pb = 0.6416 mg/kg), (Cd = 0.1910 mg/kg), and (Cr = 0.3544 mg/kg), according to the data. A number of samples were found to be above the FAO/WHO maximum allowable levels, which are 0.12 mg/kg for chromium and 0.05 mg/kg for cadmium. Apple (Cd = 0.897 mg/kg), peach (Cr = 1.289 mg/kg), and quince (Pb = 1.951 mg/kg) had the greatest values. Pb, Cd, and Cr had average estimated daily intakes (EDIs) of 0.4584, 0.1502, and 0.2532 mg/kg/day, respectively, according to the health hazard indices that were also constructed. Cd = 0.1364, Cr = 0.084, and Pb = 0.131 were the average target hazard quotient (THQ) index. The average hazard index (HI) for all metals was less than 1, at 0.351, showing no direct noncarcinogenic health harm associated with regular use. The possibility of long-term cumulative hazards, however, is indicated by samples that exceed the allowable levels, necessitating stricter food control of imported goods. The TCR (carcinogenic risk) values for lead (Pb), chromium (Cr), and cadmium (Cd) levels were assessed in dried fruit samples. The average overall TCR value was 5.106 ± 1.10, with a range of 0.002 × 10^-6 to 16.90 × 10^-6. Every one of these values falls below the acceptable ranges (10^-6 and 10^-4) established by the US Environmental Protection Agency (USEPA), suggesting that eating these fruits did not significantly increase a person's chance of developing cancer. This is one of the rare studies to focus on dried fruits in Iraq, despite the fact that there have been earlier international studies on heavy metals in fruits. In accordance with the international standards, such as THQ, HI, and TCR, it integrates chemical assessment with health analysis to produce reliable data that back up the nation's food control initiatives.

The purpose of this study is to develop and validate a simple and rapid analytical method using ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) for the simultaneous quantification of two commonly used contrast agents, iopromide and iodixanol, in human plasma. The separation of two compounds was analyzed utilizing an Agilent ZORBAX SB-C₁₈ column (2.1 × 100 mm, 3.5 μm) with an isocratic elution procedure. The mobile phase consisted of acetonitrile and 0.2% formic acid aqueous solution (14:86, V:V). A simple protein precipitation method was used to pretreat plasma samples. The iopromide and iodixanol exhibited excellent linearity between 2.0 and 400.0 μg/mL, with both R values exceeding 0.99. Recovery of iopromide ranged from 91.39% to 102.69%, and matrix effect varied between 87.88% and 104.08%; the relative standard deviation (RSD%) of intra- and interday precisions fell within the range of 1.29%-4.7%. For iodixanol, recovery ranged from 97.68% to 100.14%, and the matrix effect was between 87.88% and 96.64%, and RSD% values of intra- and interday precisions ranged from 1.58% to 8.2%. Method validation results all met methodological criteria. The UHPLC-MS/MS method was successfully developed and validated and then applied to determine two common contrast agents, iopromide and iodixanol, in human plasma.

N-nitroso-dimethylamine (NDMA, acceptable daily intake limit 96 ng/day), a probable human carcinogenic impurity, has been reported in metformin formulations. In some cases, it is difficult to accurately detect its presence due to suboptimal extraction technique(s), coelution of other probable human carcinogenic impurities such as dimethyl formamide (DMF) and/or ionization suppression in mass spectroscopic measurements. In this study, we provided a simple method to address DMF artifact using an affordable high-performance liquid chromatography coupled with a single-stage mass spectrometer. The results were further confirmed by dual-stage mass spectrometry. The two developed methods can simultaneously identify NDMA in the presence of DMF with good linear range from 10 to 100 ng/mL (r ² = 0.971) and 1 to 10 ng/mL (r ² = 0.994), respectively. The accuracy, expressed as % recovery, was close to 100% with overall precision (%RSD) < 8. The two methods were linear in the presence of 100 ng/mL DMF with r ² = 0.996 and 0.98, respectively. Five commercial formulations of metformin tablets showed traces of NDMA below the regulatory limit (0-12 ± 0.2 ng/tablet) but appreciable amounts of DMF (50-653.5 ng/tablet), still lower than the permissible daily exposure limit (8.8 mg/day) based on the maximum daily dose of metformin (5 tablets, 2500 mg). Both methods proved reliable and informative in the quality control of the NDMA content in metformin tablets and provided reciprocal verification of results.