Reported prevalence and quantitative LC-MS methods for the analysis of veterinary drug residues in honey: a review

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.

Simultaneous Screening of Nitrofuran Metabolites in Honey Using Biochip Array Technology: Validation Study According to the Decision 2002/657/EC of the European Union

Background

Although no authorization is available for antibiotics to treat bee diseases, some veterinary compounds are used by beekeepers, and each country sets its own thresholds. Inappropriate and excessive use of these drugs can cause allergic reactions and antibiotic resistance in humans who consume the remaining antibiotic residues in honey and its products. It is, therefore, relevant to monitor the presence of antibiotic residues in this matrix.

Objectives

A rapid method for the simultaneous screening of nitrofuran metabolite residues in honey was validated according to Commission Decision 2002/657/EC (C.D 657) and the European guideline for the validation of screening methods for veterinary medicines.

Methods

This multi-analytical screening method enables the simultaneous determination of four nitrofuran metabolites [3-amino-2-oxazolidone (AOZ), 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ), 1-Aminohydantoin HCl (ADH), and semicarbazide (SEC)] from a single honey sample. Thirty-five honey samples were collected randomly as real samples for screening from Tehran, IR Iran, Germany, and the Netherlands in 2018.

Results

For all four antibiotic residues, the positivity threshold T was higher than the cut-off value Fm, and no false-positive results were obtained for three antibiotics (AOZ, AMOZ, and SEC). Detection capabilities (CCβ) of all compounds were under the minimum required performance limit (MRPL) authorized by the European Commission (currently 1 μg/kg). The screening results of 15 domestic and 20 imported honey samples showed that the levels of AOZ in 6.66% and 10% of the samples, the level of AMOZ in 13.33% and 0% of the samples, and the level of SEC in 33.33% and 40% of the samples were less than the cut-off ([in relative light units (RLUs)], respectively.

Conclusions

This study found that this technique is valid for detecting and quantifying three antibiotic residues in honey samples at the measured validation levels. This method was simple, rapid, and capable of simultaneously screening three nitrofuran metabolites from a single honey sample.

Residues of antibiotics in raw honeys from different apiaries of Northern India and evaluation of human health risks

Indiscriminate use of antibiotics in apicultural practices may lead to contamination of otherwise healthy and naturally produced honey. Contamination not only affects honey quality but also pose significant health risks to consumers. In this context, one hundred raw honey samples from India were analysed for presence of antibiotic residues. For determination of oxytetracycline and erythromycin, high performance liquid chromatography and for chloramphenicol, enzyme immunoassay based validated procedures were used. Oxytetracycline and erythromycin with concentrations above maximum tolerance limits were detected in 24% and 2% samples, respectively. None of the samples contained chloramphenicol residues. Although, total dietary intake of detected antibiotics through honey was found to be <1% of their acceptable daily intake values, the presence of antibiotics in honey is an alarming health concern for people following customary honey feeding. The outcomes underline the need of inter-sectoral approaches to create awareness among beekeepers regarding health risks associated with residues of antibiotics in honey and merits of approved apicultural practices. Therefore, to meet global food safety requirements, continual residue monitoring schemes along with enlightenment of beekeepers on scientific beehive management and risks associated with incautious apicultural practices are of vital importance.

Screening of stereoisomeric chloramphenicol residues in honey by ELISA and CHARM ® II test - the potential risk of systematically false-compliant (false negative) results

Chloramphenicol (CAP) is a broad-spectrum antibiotic used widely both in human and in veterinary medication but due to adverse health effects is not authorised anymore for use in food-producing animals in many countries. CAP molecule contains two asymmetric centers resulting in four para-CAP stereoisomers, but only the RR-CAP enantiomer is bioactive with significant antimicrobial activity. In this study the detection of the four CAP stereoisomers was tested by five commercial ELISA kits and the Charm® II Chloramphenicol Test. These immunoassay tests are commonly used and widely accepted for screening of CAP residues in foods of animal origin, including honey. The test results definitely show that SS-CAP residues are not detected; even high SS-CAP concentrations are missed due to the lack of any cross reactivity and the high specificity of the CAP antibodies to RR-CAP. In former studies chiral LC-MS/MS analysis indicated clearly that honey samples with raised CAP concentrations often contain the SS-CAP enantiomer in addition to the bioactive RR-CAP. According to this study, the investigated screening tests carry the risk of systematically false-compliant (false negative) results for CAP and a discrepancy between LC-MS/MS and ELISA/Charm® test results. As a consequence of this study, it is recommended that immunoassay manufacturers develop and use CAP antibodies which also bind SS-CAP. The origin of SS-CAP residues in honey samples is discussed and general toxicological and regulatory aspects of CAP stereoisomers are raised.

Accurate Quantitation and Analysis of Nitrofuran Metabolites, Chloramphenicol, and Florfenicol in Seafood by Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry: Method Validation and Regulatory Samples

We developed and validated a method for the extraction, identification, and quantitation of four nitrofuran metabolites, 3-amino-2-oxazolidinone (AOZ), 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ), semicarbazide (SC), and 1-aminohydantoin (AHD), as well as chloramphenicol and florfenicol in a variety of seafood commodities. Samples were extracted by liquid-liquid extraction techniques, analyzed by ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), and quantitated using commercially sourced, derivatized nitrofuran metabolites, with their isotopically labeled internal standards in-solvent. We obtained recoveries of 90-100% at various fortification levels. The limit of detection (LOD) was set at 0.25 ng/g for AMOZ and AOZ, 1 ng/g for AHD and SC, and 0.1 ng/g for the phenicols. Various extraction methods, standard stability, derivatization efficiency, and improvements to conventional quantitation techniques were also investigated. We successfully applied this method to the identification and quantitation of nitrofuran metabolites and phenicols in 102 imported seafood products. Our results revealed that four of the samples contained residues from banned veterinary drugs.

Simultaneous Determination of Nitroimidazoles and Quinolones in Honey by Modified QuEChERS and LC-MS/MS Analysis

This study reports an analytical method for the determination of nitroimidazole and quinolones in honey using liquid chromatography-tandem mass spectrometry (LC-MS/MS). A modified QuEChERS methodology was used to extract the analytes and determine veterinary drugs in honey by LC-MS/MS. The linear regression was excellent at the concentration levels of 1–100 ng/mL in the solution standard curve and the matrix standard curve. The recovery rates of nitroimidazole and quinolones were 4.4% to 59.1% and 9.8% to 46.2% with relative standard deviations (RSDs) below 5.2% and the recovery rates of nitroimidazole and quinolones by the matrix standard curve ranged from 82.0% to 117.8% and 79% to 115.9% with relative standard deviations (RSDs) lower than 6.3% in acacia and jujube honey. The acacia and jujube honeys have stronger matrix inhibition effect to nitroimidazole and quinolones residue; the matrix inhibition effect of jujube honey is stronger than acacia honey. The matrix standard curve can calibrate matrix effect effectively. In this study, the detection method of antibiotics in honey can be applied to the actual sample. The results demonstrated that the modified QuEChERS method combined with LC-MS/MS is a rapid, high, sensitive method for the analysis of nitroimidazoles and quinolones residues in honey.

Decomposition of 3,5-dinitrobenzamide in aqueous solution during UV/H2O2 and UV/TiO2 oxidation processes

3,5-Dinitrobenzamide has been widely used as a feed additive to control coccidiosis in poultry, and part of the added 3,5-dinitrobenzamide is excreted into wastewater and surface water. The removal of 3,5-dinitrobenzamide from wastewater and surface water has not been reported in previous studies. Highly reactive hydroxyl radicals from UV/hydrogen peroxide (H₂O₂) and UV/titanium dioxide (TiO₂) advanced oxidation processes (AOPs) can decompose organic contaminants efficiently. In this study, the decomposition of 3,5-dinitrobenzamide in aqueous solution during UV/H₂O₂ and UV/TiO₂ oxidation processes was investigated. The decomposition of 3,5-dinitrobenzamide fits well with a fluence-based pseudo-first-order kinetics model. The decomposition in both two oxidation processes was affected by solution pH, and was inhibited under alkaline conditions. Inorganic anions such as NO₃^-, Cl^-, SO₄^2-, HCO₃^-, and CO₃^2- inhibited the degradation of 3,5-dinitrobenzamide during the UV/H₂O₂ and UV/TiO₂ oxidation processes. After complete decomposition in both oxidation processes, approximately 50% of 3,5-dinitrobenzamide was decomposed into organic intermediates, and the rest was mineralized to CO₂, H₂O, and other inorganic anions. Ions such as NH₄⁺, NO₃^-, and NO₂^- were released into aqueous solution during the degradation. The primary decomposition products of 3,5-dinitrobenzamide were identified using time-of-flight mass spectrometry (LCMS-IT-TOF). Based on these products and ions release, a possible decomposition pathway of 3,5-dinitrobenzamide in both UV/H₂O₂ and UV/TiO₂ processes was proposed.