Search Results (4)

Glyphosate-based herbicides are among the most widely used pesticides worldwide, but data on their occurrence in food products, particularly honey, remain limited. The analytical determination of glyphosate, its primary metabolite aminomethylphosphonic acid (AMPA), and glufosinate ammonium is technically challenging due to their high polarity and distinctive physicochemical properties, requiring the development of dedicated single-residue analytic methods. In this study, honey samples were prepared by derivatizing the target analytes with 9-fluorenylmethyl chloroformate (FMOC-Cl), followed by solid-phase extraction (SPE) using hydrophilic–lipophilic balanced (HLB) cartridges to improve matrix clean-up and enhance analytical sensitivity. Quantification was performed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The optimized method was validated according to the SANTE/11312/2021 guidelines, with all parameters, including sensitivity, linearity, mean recovery (accuracy), precision (RSDr), and limit of quantification (LOQ), meeting the required performance criteria. The validated method was applied to 126 honey samples of various botanical origins, representative of Italian production. The results indicated a frequent detection of glyphosate residues, although concentrations were generally low and remain below levels of regulatory concern. Full article

Memantine, a non-competitive NMDA receptor antagonist, is used to treat Alzheimer’s disease. Therefore, loading memantine in nanoparticles (NPs) could be an essential tool to improve the treatment effectiveness while reducing drug toxicity. Even though some approaches have been described to quantify memantine, none reported optimized methods using high-performance liquid chromatography resorting to ultraviolet detection (UV–HPLC) to determine encapsulation in NPs. The present research developed a HPLC method using pre-column derivatization for quantitatively analyzing memantine hydrochloride in NPs. Memantine was derivatized using 9-fluorenylmethyl chloroformate (FMOC). The developed method was fully validated regarding suitability, specificity, linearity, sensitivity, precision, accuracy, and robustness according to the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use guidelines. The retention time of memantine was 11.393 ± 0.003 min, with a mean recovery of 92.9 ± 3.7%. The new chromatographic method was validated and found to respond linearly over 5–140 μg/mL, with a high coefficient of determination. Intraday precision lay between 3.6% and 4.6%, and interday precision between 4.2% and 9.3%. The stability of memantine was also tested at 4 °C and −20 °C, and no signs of decay were found for up to 6 months. The new method was properly validated and proved simple, sensitive, specific, accurate, and precise for determining memantine encapsulation efficiency in lipid NPs. Greenness was evaluated, presenting a final score of 0.45. In the future, this methodology could also be applied to quantify memantine in different nanoformulations. Full article

The aim of this study was to develop a method for the determination of glyphosate, its metabolite aminomethylphosphonic acid (AMPA), and glufosinate ammonium residues in beebread samples, which could then be used to assess bees’ exposure to their residues. The complexity of beebread’s matrix, combined with the specific properties of glyphosate itself, required careful selection and optimization of each analysis step. The use of molecularly imprinted solid-phase extraction (MIP-SPE) by AFFINIMIP glyphosate as an initial clean-up step significantly eliminated matrix components and ensured an efficient derivatization step. Colorless beebread extracts were derivatized by the addition of 9-fluorenylmethyl chloroformate (FMOC-Cl). After derivatization, in order to remove FMOC-OH and residual borate buffer, a solid-phase extraction (SPE) clean-up step using Oasis HLB was carried out. Instrumental analysis was performed by liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS). The method was validated according to the SANTE/11312/2021 guideline at concentrations of 5, 10, and 100 µg/kg, and satisfactory recovery (trueness) values (76–111%) and precision (RSDr) ≤ 18% were obtained. The limit of quantification (LOQ) was 5 µg/kg for AMPA and glufosinate ammonium and 10 µg/kg for glyphosate. The method was positively verified by the international proficiency test. Analysis of beebread samples showed the method’s usefulness in practice. The developed method could be a reliable tool for the assessment of beebread’s contamination with residues of glyphosate, its metabolite AMPA, and glufosinate ammonium. Full article

In this study, polydimethylsiloxane (PDMS)-coated capillary columns (TRB-5 and TRB-35), both unmodified and functionalized with single-wall carbon nanotubes (SWCNTs) or multiwall carbon nanotubes (MWCNTs), have been tested and compared for the extraction of amphetamine (AMP), methamphetamine (MET) and ephedrine (EPE) by in-tube solid-phase microextraction (IT-SPME). Prior to their extraction, the analytes were derivatized with the fluorogenic reagent 9-fluorenylmethyl chloroformate (FMOC). For separation and detection capillary chromatography with fluorimetric detection has been used. The presence of carbon nanotubes in the extractive coatings enhanced the extraction efficiencies and also significantly improved the chromatographic profiles, thus resulting in a reliable option for the analysis of these drugs. As an example of application, a new method is proposed for the analysis of the tested amphetamines in oral fluid using a TRB-35 capillary column functionalized with MWCNTs. The proposed conditions provided suitable selectivity and reproducibility (CV ≤ 6%, n = 3) at low µg/mL levels, and limits of detection of 0.5–0.8 µg/mL. Full article