Electrospray ionization rapid screening sans liquid chromatography column: A sensitive method for detection and quantification of chemicals in animal tissues and urine

Sample Preparation Techniques for Growth-Promoting Agents in Various Mammalian Specimen Preceding MS-Analytics

The misuse of growth-promoting drugs such as beta-2 agonists and steroids is a known problem in farming and sports competitions. Prior to the analysis of biological samples via liquid chromatography (LC)-mass spectrometry (MS) or gas chromatography (GC)-MS, sufficient sample preparation is required to reliably identify or determine the residues of drugs. In practice, broad screening methods are often used to save time and analyze as many compounds as possible. This review was conceptualized to analyze the literature from 2018 until October 2023 for sample preparation procedures applied to animal specimens before LC- or GC-MS analysis. The animals were either used in farming or sports. In the present review, solid phase extraction (SPE) was observed as the dominant sample clean-up technique for beta-2 agonists and steroids, followed by protein precipitation. For the extraction of beta-2 agonists, mixed-mode cation exchanger-based SPE phases were preferably applied, while for the steroids, various types of SPE materials were reported. Furthermore, dispersive SPE-based QuEChERs were utilized. Combinatory use of SPE and liquid-liquid extraction (LLE) was observed to cover further drug classes in addition to beta-2 agonists in broader screening methods.

In Silico and In Vitro Studies of Antibacterial Activity of Cow Urine Distillate (CUD)

Cow urine distillate (CUD) is a traditional Indian medicine used to treat various diseases, including bacterial infections. However, there is limited evidence to support its use as a medicine, and its safety and efficacy have not been thoroughly studied. In this study, we evaluated the antibacterial activity of CUD against five bacterial strains using in vitro and in silico approaches. In vitro experiments showed that CUD has significant antibacterial activity against all tested strains with a zone of inhibition (ZOI) ranging from 13 to 24 mm and minimum inhibitory concentration (MIC) values ranging from 12.5 to 50 µg/ml. The results indicated that the 15% concentration of CUD displayed the highest antibacterial activity against Staphylococcus aureus and Salmonella typhi. To further investigate the antibacterial mechanism of CUD, we performed in silico docking studies of the active compounds of CUD with bacterial proteins involved in protein synthesis. Our results showed that 2-hydroxycinnamic acid (ΔG = -6.9 kcal/mol) and ferulic acid (ΔG = -6.8 kcal/mol) exhibited the best docking scores with the targeted proteins (DNA gyrase, PDBID: 4KFG). The hydrogen bonding interaction with amino acids Val71 and Asp73 was found to be crucial for their antibacterial activity.

Determination and enantioselective separation of zilpaterol in human urine after mimicking consumption of contaminated meat using high-performance liquid chromatography with tandem mass spectrometry techniques

RATIONALE

The synthetic β-adrenoreceptor agonist zilpaterol is legitimately used as an animal feed supplement in selected countries due to its known effects on lipolysis and protein biosynthesis. These pharmacological characteristics of zilpaterol have contributed to its classification as doping agent in sport by the World Anti-Doping Agency. However, the use as a feed supplement can lead to residues of the drug in edible tissues and, possibly, also in the urine of consumers.

METHODS

To provide urinary elimination profiles of microdosed zilpaterol and to determine whether the ingestion of zilpaterol below or at the acceptable daily intake level of 0.04 μg/kg bodyweight can result in an adverse analytical finding (AAF) in doping controls, healthy volunteers were administered single or multiple oral doses of 0.5 μg or 3 μg zilpaterol to mimic ingestion of contaminated cattle meat. Urine samples were collected and analyzed using a validated high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) method and a newly developed chiral high-performance liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry (HPLC-APCI-MS/MS) method.

RESULTS

Urinary peak concentrations of zilpaterol were observed for all volunteers 1.5-12.5 h after ingestion, and maximum levels >5 ng/mL, which would constitute an AAF in doping controls, were found after the intake of 3 μg of zilpaterol on five consecutive days in one out of five study participants. Noteworthy, the enantiomeric ratio of excreted zilpaterol remained constant over time.

CONCLUSION

This study provides first insights into the urinary excretion of microdosed zilpaterol. Furthermore, a method was successfully developed and applied for the separation of the zilpaterol enantiomers with mass spectrometric detection.

Rapid quantification of cannabinoids in beef tissues and bodily fluids using direct-delivery electrospray ionization mass spectrometry

Hempseed cake is a byproduct of hempseed oil extraction and is potentially a useful source of protein and fiber for use in ruminant diets. However, data are lacking on the appearance and/or clearance of cannabinoids in tissues of animals fed hempseed cake. To this end, a rapid method for quantifying cannabinol (CBN), cannabidiol (CBD), cannabinolic acid (CBNA), cannabidiolic acid (CBDA), cannabigerolic acid (CBGA), cannabichromenic acid (CBCA), cannabidivarin (CBDV), cannabidivarinic acid (CBDVA), tetrahydrocannabinol (THC) and tetrahydrocannabinolic acid (THCA) in cattle tissues, plasma, and urine was developed using rapid screen electrospray ionization mass spectrometry (RS-ESI-MS). Regression coefficients of matrix-matched standard curves ranged from 0.9946 to >0.9999 and analyte recoveries averaged from 90.2 ± 15.5 to 108.7 ± 18.7% across all compounds. Limits of detection and quantification ranged from 0.05 to 2.79 ng · mL^-1 and 0.17 to 9.30 ng · mL^-1, respectively, while the inter-day relative standard deviation ranged from 5.1 to 15.1%. Rapid screening electrospray ionization mass spectrometry (RS-ESI-MS) returned no false positives for any cannabinoid in plasma, urine, and tissue (liver, skeletal muscle) samples from 6 non-dosed control animals (n = 90 samples; of which 72 samples were plasma or urine and 18 samples were tissues). Across-animal cannabinoid concentrations measured in 32 plasma samples of cattle dosed with ground hemp were quantified by RS-ESI-MS; analytical results correlated well (r² = 0.963) with independent LC-MS/MS analysis of the same samples.

Evaluation of rapid and standard tandem mass spectrometric methods to analyse veterinary drugs and their metabolites in antemortem bodily fluids from food animals

Antemortem bodily fluids can serve as an indicator of veterinary medicine exposure prior to food animal slaughter. A multi-residue, rapid screen electrospray ionisation mass spectrometric (RS-ESI-MS) method was developed to analyse 10 veterinary drugs or metabolites (clenbuterol, erythromycin, flunixin, 5-hydroxyflunixin, meloxicam, ractopamine, ractopamine-glucuronide, salbutamol, tylosin, and zilpaterol) in hog oral fluid and bovine urine. Simple acetonitrile extraction with salting-out was employed to remove the analytes from matrices in less than 30 minutes. Instrumental analysis time was < 1 min/injection. Regression coefficients of matrix-matched calibration curves ranged 0.9743-0.9999 across all compounds with limits of detection ranging from 0.46-108 ng mL^-1 for cattle urine and 0.19-64.4 ng mL^-1 for hog oral fluid across all analytes. Except for ractopamine-glucuronide, analyte recoveries ranged from 92.7-106% for oral fluid and urine fortified at 30, 100, and 300 ng mL^-1, with inter-day variations of < 25%. Ractopamine-glucuronide recovery was 93.3% for oral fluid fortified at 300 ng mL^-1. The RS-ESI-MS method accurately identified ractopamine and/or ractopamine-glucuronide in incurred cattle urine with results correlating well with traditional LC-MS/MS and HPLC fluorescence methods. As far as we are aware, this is the first report of the direct quantification of ractopamine-glucuronide from biological matrices without lengthy hydrolysis and cleanup steps.

Excretion and Residual Concentration Correlations of Salbutamol Between Edible Tissues and Living Samples in Pigs and Goats

Illegal use of salbutamol (SAL), a β-adrenergic leanness-enhancing agent, has posed potential threat to human health in China. The excretion and depletion of SAL in pigs and goats were investigated, and the concentration correlations between edible tissues and living samples were analyzed to find out a suitable living sample for pre-slaughter monitoring of SAL in pigs and goats. After a single oral dosage of 1.2 mg/kg SAL, approximately 70% of the dose was excreted by pigs and goats from their excreta. When pigs and goats were supplied feed containing SAL (20 mg/kg) for 14 consecutive days, high concentrations of SAL were observed in the liver and kidneys, and the longest persistence was observed in hair. Unlike pigs, SAL was presented primarily as conjugated SAL in goats. Excellent concentration correlations of SAL were observed between urine and edible tissues both in pigs and goats, and in addition, good correlations also were found between hair and edible tissues in pigs and between feces and edible tissues in goats. Hence, urine and hair could accurately predict SAL concentrations in edible tissues of pigs, whereas feces and urine were satisfactory for predicting SAL concentrations in edible tissues of goats. These data make it possible for pre-slaughter monitoring of SAL residues in the edible tissues of pigs and goats.

Hapten synthesis and antibody production for the development of a paper immunosensor for lean meat powder zilpaterol

An anti-zilpaterol mAb with an IC₅₀ of 0.31 ng mL⁻¹ and a limit of detection (LOD) of 0.02 ng mL⁻¹ has been developed. For semi-quantitative detection in pork samples, the visual LOD is 0.5 ng mL⁻¹ and the cut-off value is 5 ng mL⁻¹.