A magnetic nanosorbent was synthesized from a ferric precursor recovered from iron mining tailings and applied in magnetic solid-phase extraction (MSPE) for the determination of bisphenol A (BPA) in aqueous matrices. An analytical method based on high-performance liquid chromatography with UV detection (HPLC–UV) was developed for the extraction and determination of BPA in water samples. BPA is classified as an emerging contaminant and an endocrine-disrupting compound due to its potential to interfere with the endocrine system. The Fe3O4@SiO2–NH2 nanosorbent was prepared using ferric ions obtained via acid leaching of mining tailings, an abundant industrial waste. The material was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), scanning electron microscopy (SEM), transmission electron microscopy (TEM), pH at the point of zero charge (pHPZC), and wettability measurements. The MSPE procedure was optimized by evaluating the elution solvent, sample pH, eluent volume, sample volume, sorbent amount, and stirring time. The method exhibited good linearity (R2 > 0.99), with limits of detection and quantification of 30 and 80 ng mL−1, respectively. Intra- and interday precision and accuracy showed relative standard deviation (RSD) and relative error (RE) values below 15
Imeglimin (IMG) is the first agent of the new tetrahydrotriazine-based class of oral antidiabetic drugs known as ‘glimins’. This work presents LC–ESI–MS based degradation profiling, by fragmentation-assisted structural elucidation of major degradation products of Imeglimin under forced degradation conditions. For that, first we have developed and validated a green, robust, simple and efficient RP-HPLC method to ensure its stability. The column used in the method is ACE CN 25 column (250 mm × 4.6 mm, 5 µm). Acetonitrile: 20 mM Ammonium Formate (60:40
Accurate determination of trace anions in electronic-grade N-methylpyrrolidone (NMP) is crucial for ensuring the reliability of lithium-ion batteries and semiconductor devices. However, severe interference from the massive organic matrix prevents conventional one-dimensional ion chromatography (1D-IC) from meeting the stringent requirements of sub-microgram-per-kilogram (µg/kg) level detection. To address this challenge, an automated, online two-dimensional ion exclusion–ion exchange chromatography (2D-ICE-IC) method integrated with a valve-switching technique was developed. By introducing ion exclusion chromatography (ICE) in the first dimension, the complex NMP matrix and potential interfering components were eliminated, leveraging the distinctly different retention behaviors between the target anions and the organic background. Combined with large-volume injection and a precisely timed valve-switching program, the heart-cut target anions were captured on a concentrator column and subsequently transferred to the second-dimensional ion exchange system for high-sensitivity analysis. Under optimized conditions, five target anions (Cl⁻, Br⁻, NO₃⁻, SO₄²⁻, and PO₄³⁻) exhibited excellent linearity within the range of 0.5–20 µg/kg (r > 0.999), with limits of detection (LODs) as low as 0.006–0.021 µg/kg. Spiked recoveries at low, medium, and high concentration levels ranged stably between 75
Solvents are needed in all branches of chemistry, and they must be eliminated after use. Impurities present in these solvents could concentrate detrimentally during chemical and, especially, pharmaceutical processes. So it is critically important to know the purity of the solvents used. The label-claimed purity of 24 solvents, including polar protic alcohols, polar aprotic carbonate esters and acetonitrile, dipolar ethers, aromatic solvents, and apolar alkanes, was tested by liquid chromatography with fluorescence detection (HPLC-FLD), gas chromatography with flame ionization or mass spectrometry detection (GC-FID or GC–MS). For all 24 tested solvents, the label-indicated purities were confirmed. The study showed that minute amounts of fluorescent impurities could be better visualized on a logarithmic scale of the emitted light rather than on the classical linear scale. Comparing the results obtained for the same solvent by HPLC-FLD and GC-FID showed that the fluorescence detector is so sensitive that it could detect an extremely low concentration of a fluorescent compound that did not produce a signal in the FID detector. However, the FID detected several more impurities than the fluorescence detector since many do not fluoresce. GC-FID and GC–MS chromatograms of the same sample on the same column showed similarities. But the strong advantage of the MS detector is impurity identification using extended modern spectral databases.
A sensitive analytical method was developed and validated for the simultaneous quantification of insulin glargine and its active metabolites M1 and M2 in human K₂EDTA plasma. Plasma sample extraction was performed using an optimized mixed-mode solid-phase extraction (SPE) procedure, followed by analysis using liquid chromatography–tandem mass spectrometry (LC–MS/MS API 6500+) in positive electrospray ionization mode. The method specificity, linearity, sensitivity, recovery, accuracy, precision, IS-normalized matrix factor, matrix effect, and stability, were systematically validated as per ICH M10 guidelines. The method exhibited high specificity, with no significant interference at the retention times of analytes and internal standards. The calibration curves showed linearity over the concentration range of approximately 70–2200 pg/mL, with regression coefficients (r2) ≥ 0.995. The lower limit of quantification was approximately 70 pg/mL for analyte and metabolites. Observed intra-day and inter-day precision (2.93–11.27
