Simultaneous determination of 10 first-generation histamine h1 receptor blockers in feeds by ultra-high-performance liquid chromatography triple quadrupole ion trap hybrid mass spectrometer.

A method for simultaneous determination of 10 first-generation histamine H1 receptor blockers in feeds by ultra-high-performance liquid chromatography triple quadrupole mass spectrometry combined with solid phase extraction. Instrument conditions, extraction solvents, and purification methods have been optimized. Under the optimum conditions, these analytes were separated effectively at 6 min. These feeds have been extracted by acid acetonitrile and purified by mixed cation exchange solid-phase extraction. The performance of this method meets the requirements of veterinary residue detection in feeds in China. It is appropriate for the confirmatory monitoring and quantitative analysis of 105 feed samples, five kinds of histamine H1 receptor blockers have been detected in 10 samples.

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.

A multicenter case-control study on postoperative intestinal fistula in Chinese patients with Crohn disease.

The aim of this study was to (1) assess the independent factors affecting patients with postoperative intestinal fistula from Crohn disease (CD) by analyzing preoperative clinical data, (2) establish a nomogram prediction model for this condition based on these factors, and (3) validate this model and evaluate its accuracy. In this retrospective multicenter case-control study, the clinical data of 240 patients with CD admitted for surgical treatment between September 2019 and September 2021 at 3 centers were collected. Patients were randomly divided into a training set (168 patients) and a validation set (72 patients). Univariate analysis was performed for relevant factors, and statistically significant factors were then analyzed using multivariate logistic regression to determine the independent influencing factors. A nomogram model for predicting postoperative intestinal fistula in patients with CD was constructed and the accuracy of the model was evaluated using calibration curves. Univariate analysis showed that disease behavior, abdominal abscess, intestinal perforation, neutrophil-to-lymphocyte ratio, systemic immunoinflammatory index, and prognostic nutrition index were factors affecting postoperative intestinal fistula in patients with CD. Multivariate logistic regression analysis showed that neutrophil-to-lymphocyte ratio, prognostic nutrition index, disease behavior, and Crohn disease activity index score were independent influencing factors. After assessing the validation set, the area under the curve was 0.899, indicating good predictive accuracy of the nomogram model. The prediction model developed in this study can effectively predict the risk of postoperative intestinal fistula.

Simultaneous determination of eight carbapenems in milk by modified QuEChERS and ultra high performance liquid chromatography coupled with high-field quadrupole-orbitrap high-resolution mass spectrometry.

A simple and accurate method of ultra high performance liquid chromatography (UHPLC) coupled with quadrupole-high field Orbitrap high-resolution mass spectrometry (QE HF HRMS) has been developed for analyzing 8 trace-level (µg/L) carbapenems in milk. Mass spectrometry conditions, chromatographic conditions, extraction solvent and QuEChERS procedures were optimized for determination of 8 carbapenems in milk. Samples were extracted and purified by modified QuEChERS procedure. Good separation for 8 carbapenems s was achieved with a PFP column at 8 min. Method validation results showed the linear ranges are 1-100 µg/L to 10-1,000 µg/L, the correlation coefficients are more than 0.995, and the recoveries of spiked samples are 79.3%-104% with a relative standard deviation less than 15%. This method successfully applied to monitor residue of carbapenems in real milk, four kinds of carbapenems have been detected in 8 sample of 79 collected milks with concentration ranged between 15 µg/L∼3,325 µg/L.

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.

Trace analysis and identification of 33 sulfonamides and sulfonamide potentiators in eggs by ultrahigh-performance liquid chromatography coupled with quadrupole-high-field orbitrap high-resolution mass spectrometry.

A method was established for the simultaneous trace analysis and identification of 27 sulfonamides and 6 sulfonamide potentiators in eggs by ultrahigh-performance liquid chromatography coupled with quadrupole-high-field orbitrap high-resolution mass spectrometry and multifunction impurity adsorption cleaning. The appropriate extraction, purification, and instrument conditions were optimized. The drugs were extracted by acetonitrile with 1% formic acid and purified with optimized adsorption material based on multifunction impurity adsorption cleaning. The elution was evaporated by nitrogen blowing, dissolved, and then assayed. The limits of detection were 0.01-0.28 µg kg-1 for all drugs, while the recoveries were 82.4-110.6%, the relative standard deviations were 2.5-14.9%, and the linearity of the drugs in the corresponding concentration range was greater than 0.995. The proposed method was successfully applied for the monitoring of sulfonamides and their potentiators in egg samples, whereby 4 sulfonamides and 3 sulfonamide potentiators were detected in 200 egg samples.

Trace analysis of progesterone and 21 progestins in milk by ultra-performance liquid chromatography coupled with high-field quadrupole-orbitrap high-resolution mass spectrometry.

A method for rapid screening and quantification of progesterone and progestins in milks by ultrahigh-performance liquid chromatography coupled with quadrupole-high field Orbitrap high-resolution mass spectrometry (UHPLC QE HF HRMS) was established. Milks samples were extracted by acetonitrile + hexane (80 + 20), purified by prime HLB SPE and analyzed by UHPLC QE HF HRMS. The detection limit of progesterone and 21 progestins in milk is between 0.05 µg/kg -0.3 µg /kg, the correlation coefficient of progesterone and progestins in the corresponding concentration range is more than 0.99, recoveries for milk samples are between 80.7% and 108.3% with the relative deviation is less than 15%.The method fulfils the requirements of veterinary drug residue detection validation of EU and China, and successfully applied to detecting the µg/kg level of progesterone and monitoring residual of progestins in real milk.

Simultaneous determination of antibiotics and amantadines in animal-derived feedstuffs by ultraperformance liquid chromatographic-tandem mass spectrometry.

In this study, a method for simultaneous determination of 40 antibiotics from 6 different drug families (7 quinolones, 5 penicillins, 8 macrolides, 2 lincosamides, 4 tetracyclines, and 13 sulfonamides) and 3 amantadines in animal-derived feedstuffs (ADF) through ultraperformance liquid chromatography-tandem mass spectrometry using a new lipid-removing solid-phase extraction column PRiME HLB was developed. The sample was extracted with 20 mL extraction solution and then purified and concentrated with PRiME HLB. The eluent was evaporated to dryness under nitrogen and analyzed with LC-MS/MS using acetonitrile and 0.1% formic acid as the mobile phase via gradient elution. Under the optimum conditions, recoveries were 65.8% to 104.4% with a relative standard deviation of <15% at spiked levels of 5.0 µg/kg to 100 µg/kg. The limits of detection ranged from 0.5 µg/kg to 5 µg/kg. 15 of the 43 drugs were found in ADF. Sulfonamides, fluoroquinolones, macrolides, tetracyclines, and amantadines were detected, with the highest levels reaching 325 µg/kg.