This study developed a rapid and reliable liquid chromatography high-resolution mass spectrometry (LC-HRMS) method for the simultaneous determination of 8 alkylamines and 12 alkylamides in meat products. Sample preparation and instrumental conditions were optimized to achieve efficient extraction and accurate quantification. Meat samples were extracted with methanol-acetonitrile mixture (1:1, v / v ) using vortex-ultrasonication for 15 min, followed by evaporation and reconstitution prior to analysis. The mobile phases were ultrapure water containing 0.1% formic acid and acetonitrile, and a gradient elution program was employed. Mass spectrometric analysis was performed in positive electrospray ionization mode with full scan and data-dependent acquisition. Quantification was carried out using an internal standard method. The limits of quantification were 5 ng/g, and calibration curves showed good linearity. Recoveries ranged from 85.2% to 103.0% with relative standard deviations (RSDs) of 0.3-8.0%, and matrix effects ranged from 61.7% to 109.6% with RSDs of 0.2-10.3%. The method was successfully applied to meat samples collected from local markets, with concentrations of individual alkylamines and alkylamides ranging from below the detection limit to 13105.0 ng/g. Migration experiments indicated that alkylamines and alkylamides could transfer from plastic materials into meat, with migration extent increasing with the increase of contact time and temperature. Hydrophobic alkylamides migrated more rapidly in early stage, while some alkylamines continued to migrate at low temperatures, indicating that meat characteristics and contact conditions could significantly affect the migration. The developed method is suitable for the determination of alkylamines and alkylamides in meat products, and can provide a reference approach for assessing the potential migration and exposure risks of alkylamines and alkylamides.
Highly selective extraction of Pd from leaching liquor of spent auto-catalysts is a research hotspot in recent years. In this study, three novel octanethioic acid alkyl amide extractants (alkyl = butyl TA-804, hexyl TA-806 and 2-ethylhexyl TA-826) were designed, synthesized and characterized by 1 H NMR, FT-IR and ESI-HRMS. The effect of contact time, extractant concentration, HCl concentration and diluents on Pd selective extraction and separation by these three extractants were investigated. The stripping behaviors of the loaded Pd in the organic phase were examined. The McCabe-Thiele diagrams of Pd extraction and stripping were drawn. The extraction mechanism was studied through methods of stoichiometry calculation, slope analysis, FT-IR and ESI-HRMS. In the end, the Pd separation from simulated leaching liquor of spent auto-catalysts by TA-804, TA-806 and TA-826 was carried out. The results show TA-826 has much slow Pd extraction kinetics than TA-804 and TA-806. They all have highly efficient extraction and separation performance for Pd from chloride media at acidities of [HCl] ≤ 3 mol/L. When the HCl concentration is ≥4 mol/L, Fe and Pt begin to be extracted. At any acidities, Rh, Zn, Al, La, Zr, Co, Cu, Ni, Ce and Mg are not extracted. The studied octanethioic acid alkyl amides extract Pd from chloride media via complexation mechanism. Two extractant molecules quantitatively extract one Pd. The loaded Pd are easily and efficiently stripped by thiourea. They can efficiently extract and highly separate Pd from leaching liquor of spent auto-catalysts at acidity of 3 mol/L HCl.
The hydrate blockage avoidance performance of two anti-agglomerants (coconut amidopropyl dimethylamine, propylene bis (octadecylamidopropyl dimethylammonium chloride)) and their mixtures with polyvinylpyrrolidone (PVP) was tested in a high-pressure rocking cell apparatus. The effect of gas–liquid ratio, water content and PVP concentration were analyzed. A method for evaluating the kinetic inhibiting and anti-agglomerating performance of hydrate inhibitors was established. It was found that coconut amidopropyl dimethylamine had good anti-agglomerating performance at a low gas–liquid ratio (0.5) and various water content levels (20~80%), while propylene bis (octadecylamidopropyl dimethylammonium chloride) had a good anti-agglomerating performance only at a low gas–liquid ratio (0.5) and high water content (80%), and the hydrate volume fraction was up to 23.27% for good anti-agglomeration. When PVP was mixed with the above two anti-agglomerants, it was found that coconut amidopropyl dimethylamine could significantly reduce the kinetic inhibition performance of PVP, while propylene bis (octadecylamidopropyl dimethylammonium chloride) had no significant effect on the kinetic inhibition performance of PVP. The maximum subcooling was 4.4 °C. PVP had no significant effect on the anti-agglomerating performance of the two anti-agglomerants, and the maximum hydrate volume fraction was 18.87% when the agglomeration was well inhibited.
危险品化学品经营许可证（带存储）