Trace analysis of 20 antihistamines in milk by ultrahigh performance liquid chromatography coupled with high field quadrupole orbitrap high resolution mass spectrometry followed dispersive micro solid phase extraction.

Ultrahigh-performance liquid chromatography coupled with high-field quadrupole Orbitrap high resolution mass spectrometry was used for the separation and determination of 20 antihistamines, and a dispersive micro solid-phase extraction procedure using high-performance absorbing material was developed as a sample preparation strategy for extracting 20 antihistamines from milk. Instrument conditions and key parameters influencing extraction efficiency were investigated to obtain an optimized method. The limit of detection for 20 antihistamines in milk using this method is 0.05 µg/L to 1.0 µg/L. Recoveries are between 80.7 % and 108.3 %, and the relative standard deviation is less than 15 %. It is suitable for confirmatory monitoring and quantitative analysis of 20 antihistamines in milk. The results show that antihistamines in milk may be noteworthy issues for human health and environmental pollution.

Multi-residue determination of five quinoxalines and three their metabolites in poultry feathers and its application for depletions of olaquindox and quincetone in chickens.

A method for the simultaneous determination of eight quinoxalines and their metabolites in poultry feathers was developed in this study using ultra-performance liquid chromatography combine with quadrupole linear ion trap electrostatic field orbit trap high resolution mass spectrometer. Specificity, matrix effect, linearity, trueness, repeatability, reproducibility, and stability using the Commission of the European Communities, Regulation (EU) 2021/808. The correlation coefficients were all greater than 0.99. The average recoveries of the eight compounds ranged from 76.1% to 112.8%, with coefficient of variation of less than 15%. The limits of detection and quantification of the method were 0.04-0.1 µg/kg and 0.12-0.3 µg/kg, respectively. The method has been successfully applied to depletions of olaquindox and quincetone in feathers of laying hens. Methylquinoxaline-2-carboxylic acid and quincetone are the main metabolites in olaquindox and quincetone in feather, respectively.

Residue accumulation, distribution, and withdrawal period of sulfamethazine and N-acetylsulfamethazine in poultry waste from broilers.

Sulfamethazine is one of the most frequently used sulfonamides in the poultry farming industry. However, the residue accumulation, distribution, and depletion of sulfamethazine (SMZ) and its metabolite, N4-acetylsulfamethazine (NAS), in poultry waste (manure and feathers) have yet to be evaluated. In our study, the residue levels of SMZ and NAS in manure and feathers are determined by liquid chromatography tandem mass spectrometry. Furthermore, the distribution, depletion, and withdrawal period of SMZ and NAS in manure and feathers are investigated under field conditions. Results show that high concentrations (0.7-43.3 mg/kg for SMZ, and 0.22-22.4 mg/kg for NAS) of SMZ and NAS residues remain in manure and feathers even when SMZ has been used. The withdrawal periods of SMZ and NAS in feathers are 97.0 d and 28.0 d, respectively. In manure, the withdrawal period is 18.2 d and 8.0 d, respectively. Poultry waste is a possible major reentry way of SMZ into the food chain and the environment.