A novel, green, stability-illustrating HPLC-DAD method was validated for the simultaneous analysis of menadione (MND), dimetridazole (DMT), and sulfadimethoxine sodium (SLF) in a veterinary powder for the first time. These compounds are commonly combined in veterinary premixes and powders to enhance animal growth, prevent bacterial infections, and improve feed efficiency. Separation was achieved isocratically on a C18 column using a mobile phase of 0.05M KH₂PO₄: acetonitrile (80:20,v/v) at a flow rate of 2.0 mL/min, with detection at 260 nm. The represented HPLC-DAD method was rapid, yielding retention times under 5.2 min, and exhibited excellent linearity over the tested ranges (10.0–30.0, 20.0–60.0, and 20.0–60.0 µg/mL for MND, DMT, and SLF, respectively). Forced degradation studies, conducted according to the International Council for Harmonisation (ICH) guidelines, confirmed the method’s specificity in distinguishing the active pharmaceutical ingredients from their degradation products. The highest degradation was observed for MND (photolytic, 26.52%), DMT (alkaline, 21.12%), and SLF (oxidative, 27.16%). The method’s environmental sustainability was evaluated using the Analytical GREEnness (AGREE) metric (score: 0.75) and the Green Analytical Procedure Index (GAPI), while its practicality was supported by a high Blue Applicability Grade Index (BAGI) score of 80.0. This stability-indicating method represents the first robust, green, and reliable analytical approach for this triple veterinary formulation.

The long-term reliability of catalytic gas sensors is strongly influenced by changes in the chemical state and cleanliness of the catalyst surface. In this work, we investigate the surface composition and stability of the platinum (Pt) nanoparticle catalytic layer in Gas Metal-Oxide-Semiconductor (GMOS) sensors under varying environmental conditions. Using X-ray Photoelectron Spectroscopy (XPS) and High-Resolution (HR) XPS, we compared fresh, aged samples, thermally treated samples, and samples stored with or without a mechanical filter. The results show that prolonged ambient storage leads to the accumulation of adventitious carbon and nitrogen-containing species, as well as partial oxidation of platinum, which reduces the number of active metallic Pt sites. Thermal treatment at 300 °C for 30 min restores metallic Pt exposure by removing surface contaminants and narrowing the Pt 4f peaks. However, recontamination occurs during subsequent storage, with significant differences depending on surface protection. Sensors equipped with a mechanical filter exhibited obvious Pt metallic peaks in HR-XPS analysis, with lower carbon and nitrogen levels, compared to unprotected samples. These findings demonstrate that while heating refreshes catalytic activity, long-term stability requires complementary filtration to prevent re-adsorption of airborne species. The combined approach of heating and filtration is thus essential to ensure reliable performance of GMOS sensors for indoor and outdoor air quality monitoring.

The complexity of the milk matrix, driven by its lipid-rich composition, complicates pesticide residue analysis. This study developed a simplified and robust analytical procedure for the quantification of 250 pesticides in cow’s milk. Sample preparation involved acidified ethyl acetate extraction followed by centrifugation at 0 °C. A subsequent clean-up step was performed using micro solid-phase extraction (μSPE) in a 96-well format with the enhanced matrix removal-lipid (EMR-lipid) sorbent. Final extracts were analyzed by gas chromatography coupled to high-resolution mass spectrometry (GC-Q-Orbitrap-MS). Method validation demonstrated satisfactory linearity within the 5–100 µg/L range, recoveries between 70.6% and 119.8%, and precision, expressed as relative standard deviation (RSD), was acceptable for both intraday (1.8–19.2%) and interday (1.6–18.5%) conditions. The limit of quantification (LOQ) was set at 10 µg/kg for all compounds. The method was applied to 23 commercial cow’s milk samples, and no pesticide residues were detected above the current European Union (EU) maximum residue limits (MRLs).