Chinese chicken broth is well known for its outstanding nutritional value and flavor, widely consumed in China. This study was designed to develop a sensitive and accurate high-performance liquid chromatography-variable wavelength detector (HPLC-VWD) method to simultaneously determine purines and uric acid in Chinese chicken broth for gout and hyperuricemia dietary management. Chromatographic separation was performed on an Agilent TC-C18 (2) column (4.6 mm × 250 mm, 5.0 µm), using 0.02 M KH₂PO₄ (pH 4.0) as a mobile phase. Sample pretreatment was optimized to enable the extraction of all analytes from Chinese chicken broth. The optimal pretreatment conditions were chicken broth-60% trifluoroacetic acid (TFA)/20% formic acid (FA) (1:1, v/v) in a volume ratio of 1:3 and hydrolysis for 40 min at 85 °C in a water bath. The limits of detection (LODs) and limits of quantification (LOQs) of the purines and uric acid were 0.58–1.71 µg/L and 1.92–5.70 µg/L, respectively. The recoveries were 91–101%, with the relative standard deviations (RSDs) lower than 3%. The complete method has been successfully applied to determine purines and uric acid in various Chinese chicken soups obtained from different provinces in China.

β-agonists are illegally added to animal feed because they can greatly increase carcasses’ leanness, which impairs the safety of animal-derived foods and indirectly endangers human health. This study aimed to develop an ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for determining sixteen β-agonists in livestock meat. The homogenized samples were subjected to enzymatic hydrolysis using β-glucuronidase/sulfatase at 40 °C for 2 h, extracted with acetonitrile containing 1% acetic acid (v/v), and purified by the one-step Qvet-AG extraction column. The residue was redissolved by 0.1% aqueous formic acid/methanol (9:1, v/v) after blow-drying by nitrogen, and then determined by UHPLC-MS/MS. The results demonstrated that the well linearity was in the range of 0.1–50 μg/L with the correlation coefficient (R²) ≥0.9928, and the limits of detection (LOD) and quantification (LOQ) were 0.01–0.11 μg/kg and 0.04–0.38 μg/kg, respectively. With intraday and interday relative standard deviations (RSDs) being less than 10%, the average recoveries of pork, beef, and lamb at various spiked levels ranged from 62.62–115.93%, 61.35–106.34%, and 62.00–111.83%, respectively. In conclusion, the established method is simple, efficient, sensitive, and suitable for the simultaneous detection of several β-agonist residues in livestock meat.

Purpose: To undertake comparative kinetic and thermodynamic analyses of the interaction of bovine serum albumin (BSA) with IgG pre-treated with ultra-high pressure (UHP) and moderate heat. Methods: BSA solutions were processed at 100 – 600 MPa and 25 – 40 °C. We applied an optical biosensor based on surface plasmon resonance (SPR). The dissociation and association kinetics of antigen-antibody complexes were measured at different temperatures. By analyzing the resultant sensograms, the association rate constant (ka), dissociation rate constant (kd), equilibrium dissociation constant (KD), and thermodynamic parameters were calculated. Results: The equilibrium disassociation constant, KD, ranged from a low value of 3.15 × 10⁻⁷ M (0.1 MPa, 25 °C) to a high value of 66.42 × 10⁻⁷ M (600 MPa, 55 °C). Increase in pressure and temperature led to decrease in the affinity of BSA for IgG. Pressure levels above 300 MPa promoted interactions between breakage of disulfide bonds, and the unfolding and aggregation of BSA. Conclusions: These results show that the combination of UHP and moderate heat treatment cdecrease the allergenicity of BSA by changing their protein conformation. Keywords: Ultra - high pressure, Bovine serum albumin, Surface plasmon resonance, Kinetics, Thermodynamics, Allergens

Anabolic androgenic steroids (AASs) are usually illegally added to animal feed because they can significantly promote animal growth and increase carcasses’ leanness, which threatens the safety of animal-derived foods and indirectly hazards human health. This study aimed to establish an ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC–MS/MS) method for the simultaneous detection of twelve AAS residues in livestock and poultry meat. The homogenized samples were extracted with acetonitrile containing 1% acetic acid (v/v) and purified using the one-step extraction column. After concentration using nitrogen, the residues were redissolved in acetonitrile and then quantified with an external standard method using UHPLC–MS/MS. The results showed that the above-mentioned method had a satisfactory linear correlation (R² ≥ 0.9903) with a concentration range of 1–100 μg/L, and the limits of detection (LODs) and quantification (LOQs) were 0.03–0.33 μg/kg and 0.09–0.90 μg/kg, respectively. With the intraday and interday precision less than 15%, the average recoveries of pork, beef, lamb, and chicken, at different spiked levels, ranged from 68.3 to 93.3%, 68.0 to 99.4%, 71.6 to 109.8%, and 70.5 to 97.7%, respectively. Overall, the established method is validated, precise, and capable of the high-throughput determination of the residues of twelve AASs in livestock and poultry meat.

Amphenicols are widely used to prevent and treat animal diseases. However, amphenicol residues accumulate in livestock and poultry and harm consumers. We hypothesized that one can combine solid-phase extraction (SPE) with ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) to simultaneously determine amphenicols and metabolites in pork, beef, lamb, chicken, and their products and meet government regulations for maximum residue limits. We extracted crude samples with ethyl acetate and ammonia water (98:2, v/v), purified the samples with a CNW Si SPE column, defatted the samples with acetonitrile-saturated n-hexane, and then determined the resulting analytes by UHPLC-MS/MS. The limit of detection of the analytes in livestock and poultry meat was 0.031.50μg/kg, and the limit of quantification was 0.055.00μg/kg. Measured chloramphenicol, thiamphenicol, and florfenicol concentrations were linear over the range 0.5050μg/kg; and the florfenicol amine concentration was linear over the range 5.00200μg/kg (all with correlation coefficients >0.9990). The recovery of the spiked samples was between 72 and 120. The intraday relative standard deviation (RSD) ranged from 1 to 9, and the interday RSD ranged from 1 to 12. Based on the above results, the current method is sensitive, accurate, and reproducible with the detection limits being well below the maximum residue limits as per Chinese standard GB 31650-2019, and thus, our research hypothesis could be confirmed.