QuEChERS with Magnetic Hydrophilic–Lipophilic Balanced Adsorbent and Its Application in Multi-Class Veterinary Residues in Milk by Ultra High-Performance Liquid Chromatography-Tandem Mass Spectrometry

Advances in magnetic analytical extraction techniques for detecting antibiotic residues in edible samples

The widespread use of antibiotics in agricultural and animal husbandry to treat bacterial illnesses has resulted in a rise in antibiotic-resistant bacteria. These bacteria can grow when antibiotic residues are present in food items, especially in edible animal products. As a result, it is crucial to monitor and regulate the amounts of antibiotics in food. Magnetic analytical extractions (MAEs) have emerged as a potential approach for extracting antibiotic residues from food using magnetic nanoparticles (MNPs). Recent improvements in MAEs have resulted in the emergence of novel MNPs with better selectivity and sensitivity for the extraction of antibiotic residues from food samples. Consequently, this review paper addresses current developments in MAE for extracting antibiotic residues from edible samples. It also provides a critical analysis of contemporary MAE practices. The current issues and potential future developments in this field are also discussed, thereby providing a framework for future study paths.

Rapid multi-residue LC-MS/MS determination of nitrofuran metabolites, nitroimidazoles, amphenicols, and quinolones in honey with ultrasonic-assisted derivatization - magnetic solid-phase extraction

A rapid multi-residue LC-MS/MS method for the identification and determination of banned veterinary drugs in honey was developed. A total of 31 investigated veterinary drugs belonging to 4 classes including nitrofurans metabolites, nitroimidazoles, amphenicols, and quinolones were quantified by LC-MS/MS with ESI using one single injection. The sample preparation included treatment with 5-nitro-2-furaldehyde (5-NFA) in a thermostated ultrasonic bath (80 °C, 0.5М НСl, 20 min) to liberate matrix-bound residues of nitrofurans. Magnetic hypercrosslinked polystyrene (HCP/Fe3O4) was proposed for the solid-phase extraction and clean-up of target analytes prior to LC-MS/MS analysis. To evaluate and validate the performance of method, the criteria of the Decision (EC) no 2002/657 were applied. The LOQs of the examined analytes range from 0.3 to 1 μg kg-1, which indicates good sensitivity to quantify the target compounds in honey. The recoveries of veterinary drugs from 1 g of honey with 50 mg of the sorbent are 97-109% for nitrofuran metabolites, 84-115% for nitroimidazoles, 86-103% for amphenicols, and 97-118% for quinolones. The relative standard deviations of intra-day and inter-day precision analyses (RSD) are less than 16%. This methodology was applied to real honey samples and trace levels of some veterinary drugs were detected.

Analysis, Occurrence and Exposure Evaluation of Antibiotic and Anthelmintic Residues in Whole Cow Milk from China

An optimized QuEChERS method for the simultaneous extraction of 26 antibiotics and 19 anthelmintics in whole cow milk was established, followed by UHPLC-MS/MS analysis. Briefly, 20 mL acetonitrile with 1 g disodium hydrogen citrate, 2 g sodium citrate, 4 g anhydrous MgSO₄, and 1 g sodium chloride were added to 10 g milk for target chemical extraction, followed by 50 mg anhydrous MgSO₄ for purification. Satisfactory recoveries were obtained using the modified QuEChERS method, with recoveries of the antibiotics ranging from 79.7 to 117.2%, with the exception of norfloxacin, which was at 53.4%, while those for anthelmintics were in the range of 73.1-105.1%. The optimized QuEChERS method presented good precision, with relative standard deviations ranging from 7.2 to 18.6% for both antibiotics and anthelmintics. The method was successfully applied to analyze the antibiotics and anthelmintics in 56 whole cow milk samples from China. Briefly, the detection frequencies and concentrations of most of the antibiotics and anthelmintics were low in the whole cow milk samples, with concentrations ranging from below LOD to 4296.8 ng/kg. Fenbendazole, febantel, enrofloxacin, levofloxacin, sulfadiazine, and sulfamethoxazole were the predominant drug residues in the whole cow milk samples. Spatial distribution was found for those antibiotics and anthelmintics with detection frequency higher than 50%, especially for the antibiotics, indicating regional differences in drug application. Based on the current study, exposure to antibiotics and anthelmintics through whole cow milk consumption are lower than the acceptable daily intake values suggested by the China Institute of Veterinary Drug Control. However, long-term exposure to low doses of antibiotics and anthelmintics still needs attention and merits further study.

Challenges for the determination of spiramycin in aqueous matrices using LC-MS/MS: evidence for the solvent intrusion on the molecule integrity

Liquid chromatography-tandem mass spectroscopy (LC-MS/MS) is an accurate and specific technique for drug residue analysis in different matrices. The high specificity and sensitivity of the multiple reaction monitoring (MRM) approach for detecting drugs such as aldehydes, which have the potential to change mass during the sample preparation phase, becomes a drawback during the analysis process. In this study, concerns about the intrusion of solvent molecules into spiramycin's chemical structure as an aldehydic drug as well as the stability of spiramycin in the milk matrix were addressed. Furthermore, the binding sites where the solvent molecules could bind to spiramycin molecules were investigated through nuclear magnetic resonance (NMR) spectroscopy. It was revealed that water, ethanol, and methanol as protic solvents can add to the formyl group of spiramycin molecules during standard solutions preparation while there was no evidence for the addition of acetonitrile and dimethyl sulfoxide (aprotic solvents). In addition, as time passed, the peak area of spiramycin decreased either in the spiked aqueous sample or milk sample while an increase in the peak area of H₂O-bound spiramycin was observed. After 96 h, more than 90% of spiramycin was converted to H₂O-bound spiramycin. In conclusion, we can propose the use of aprotic solvents for the preparation of spiramycin standard solutions especially when the prepared solutions are not used instantly. Moreover, ion transitions for both spiramycin and its H₂O-added form (843.6 m/z to 173.9 m/z and 861.5 m/z to 173.9 m/z, respectively) should be considered for the accurate quantification of spiramycin residue in aqueous samples such as milk.

Water, ethanol, and methanol as protic solvents can add to the formyl group of spiramycin molecules during standard solutions preparation while there was no evidence for the addition of acetonitrile and dimethyl sulfoxide as aprotic solvents.

Multi-class, multi-residue determination of 132 veterinary drugs in milk by magnetic solid-phase extraction based on magnetic hypercrosslinked polystyrene prior to their determination by high-performance liquid chromatography-tandem mass spectrometry

A quantitative multi-class multi-residue analytical method was developed for the determination of veterinary drugs in milk by high-performance liquid chromatography - tandem mass spectrometry (HPLC-MS/MS). A total of 132 veterinary drugs investigated belonged to almost 15 classes including sulfonamides, β-lactams, tetracyclines, quinolones, macrolides, nitrofurans, nitroimidazoles, phenicols, lincosamides, pleuromutilins, macrocyclic lactones, quinoxaline antibiotics, benzimidazoles, anthelmintics, coccidiostats and some others. A magnetic solid-phase extraction procedure was developed using magnetic hypercrosslinked polystyrene (HCP/Fe₃O₄) for the sample preparation prior to HPLC-MS/MS without deproteinization step. The results indicated recoveries of 85-107% for 14 sulfonamides, 85-120% for 13 β-lactams, 89-115% for 4 tetracyclines, 82-119% for 14 quinolones, 82-115% for 8 macrolides, 97-109% for 4 nitrofurans, 84-115% for 10 nitroimidazoles, 89-114% for 3 phenicols, 86-111% for 3 lincosamides, 97-102% for 2 pleuromutilins, 72-88% for 4 macrocyclic lactones, 87-104% for 4 quinoxaline antibiotics, 76-119% for 21 benzimidazoles, 79-115% for 12 anthelmintics, 81-118% for 12 coccidiostats and 75-119 % for 5 unclassified drugs, with relative standard deviations (RSDs) of less than 20%, and the LOQs ranged from 0.05 to 1 μg kg^-1. This methodology was then applied to field-collected real milk samples and trace levels of some veterinary drugs were detected.