Confirmation of 13 sulfonamides in honey by liquid chromatography–tandem mass spectrometry for monitoring plans: Validation according to European Union Decision 2002/657/EC

Analyzing antibiotic residues in honey samples using liquid chromatography-tandem mass spectrometry

This study aimed to present a sensitive, accurate, and precise analytical method for the determination of 32 antibiotics from 5 groups (sulfonamides, macrolides, aminoglycosides, tetracyclines, and quinolones) and some individual antibiotics (lincomycin, griseofulvin, and 5-hydroxy-flunixin) in 63 honey samples collected from Tehran market. In the presented method, the samples were hydrolyzed by 1% HFBA (hepta fluoro butyric acid) in water, purified on Strata XL polymeric reversed-phase cartridges, and finally analyzed by reversed-phase ion-pair liquid chromatography-electrospray ionization tandem mass spectrometry (RP-IP-LC-ESI-MS/MS). Good performance characteristics were gained for recovery, precision, range, and linearity, the limit of detections (LODs), and the limit of quantifications (LOQs). According to the presented results and considering the absence of permissible limits for antibiotics in honey, 74.6% of the tested samples had antibiotic residues more than the LOQ of the method. The results show that the validated method is suitable for simultaneously detecting antibiotic residues in honey.

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.

Carbon Black Integrated Polylactic Acid Electrodes Obtained by Fused Deposition Modeling: A Powerful Tool for Sensing of Sulfanilamide Residues in Honey Samples

Sulfanilamide (SFL) is used to prevent infections in honeybees. However, many regulatory agencies prohibit or establish maximum levels of SFL residues in honey samples. Hence, we developed a low-cost and portable electrochemical method for SFL detection using a disposable device produced through 3D printing technology. In the proposed approach, the working electrode was printed using a conductive filament based on carbon black and polylactic acid and it was associated with square wave voltammetry (SWV). Under optimized SWV parameters, linear concentration ranges (1-10 μmol L^-1 and 12.5-35.0 μmol L^-1), a detection limit of 0.26 μmol L^-1 (0.05 mg L^-1), and suitable RSD values (2.4% for inter-electrode; n = 3) were achieved. The developed method was selective in relation to other antibiotics applied in honey samples, requiring only dilution in the electrolyte. The recovery values (85-120%) obtained by SWV were statistically similar (95% confidence level) to those obtained by HPLC, attesting to the accuracy of the analysis and the absence of matrix interference.

Fate of Sulfonamides and Tetracyclines in Meat during Pan Cooking: Focus on the Thermodegradation of Sulfamethoxazole

Although antimicrobials are generally found in trace amounts in meat, the human health risk they bear cannot be ignored. With the ultimate aim of making a better assessment of consumer exposure, this study explored the effects of pan cooking on sulfonamides and tetracyclines in meat. Screening of these antimicrobials in cooked meat was first performed by the European Union Reference Laboratory on the basis of HPLC-MS/MS analyses. A proof of concept approach using radiolabeling was then carried out on the most cooking-sensitive antimicrobial—sulfamethoxazole—to assess if a thermal degradation could explain the observed cooking losses. Degradation products were detected thanks to separation by HPLC and monitoring by online radioactivity detection. HPLC-Orbitrap HRMS analyses completed by 1D and 2D NMR experiments allowed the structural characterization of these degradation compounds. This study revealed that cooking could induce significant antimicrobial losses of up to 45% for sulfamethoxazole. Six potential degradation products of ¹⁴C-sulfamethoxazole were detected in cooked meat, and a thermal degradation pattern was proposed. This study highlights the importance of considering the cooking step in chemical risk assessment procedures and its impact on the level of chemical contaminants in meat and on the formation of potentially toxic breakdown compounds.

Application of MnO2 Nanorod–Ionic Liquid Modified Carbon Paste Electrode for the Voltammetric Determination of Sulfanilamide

The current work introduced a convenient single-phase hydrothermal protocol to fabricate MnO₂ nanorods (MnO₂ NRs). Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX) and field-emission scanning electron microscopy (FE-SEM) were used to determine the characteristics of MnO₂ NR. Then, ionic liquid (IL) and MnO₂ NRs were utilized to modify a carbon paste electrode (CPE) surface (MnO₂NR-IL/CPE) to voltammetrically sense the sulfanilamide (SAA). An enhanced voltammetric sensitivity was found for the as-developed modified electrode toward SAA when compared with a bare electrode. The optimization experiments were designed to achieve the best analytical behavior of the SAA sensor. Differential pulse voltammetry (DPV) in the optimized circumstances portrayed a linear dependence on various SAA levels (between 0.07 and 100.0 μM), possessing a narrow detection limit (0.01 μM). The ability of the modified electrode to be used in sensor applications was verified in the determination of SAA present in the actual urine and water specimens, with impressive recovery outcomes.

Rapid determination of multi-antibiotic residues in honey based on modified QuEChERS method coupled with UPLC-MS/MS

Antibiotic residues in honey cause public health problems. To analyze multi-antibiotic residues in honey, a modified QuEChERS (quick, easy, cheap, effective, rugged and safe) extraction method coupled with ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed for simultaneous quantification of 70 antibiotic residues in honey. Matrix-matched calibrations indicated the correlation coefficients were higher than 0.998. The recovery was in a range of 70.5%-119.8% with intra-day relative standard deviation (RSD) of ≤ 10.0% and inter-day RSD of ≤ 13.9%. The limits of detection ranged between 0.050 μg/kg and 1.02 μg/kg. Limits of quantification was 0.17 μg/kg to 3.40 μg/kg. The matrix effects were negligible in 71.4% of compounds and moderately in 24.3% of compounds. Methacycline, oxytetracycline, tetracycline and its metabolite 4-tetracycline residues were detected in the tested samples. Validation parameters were acceptable and were in line with the Codex guidelines. This method was effective for detecting multi-antibiotic residues in honey.

Assessment of the impact of hydrolysis on bound sulfonamide residue determination in honey using stable isotope dilution ultrahigh performance liquid chromatography tandem mass spectrometry

In this study, an analytical method based on isotope dilution-liquid chromatography tandem mass spectrometry (ID-LC-MS/MS) was developed as a candidate reference method for the determination of sulfonamides (SAs) in honey. To guarantee the accuracy and authenticity, the impact of hydrolysis on bound SA residues was first investigated by enabling (i) identification of sugar-bound SAs, (ii) clarifying the binding reaction rule between the SAs and sugar, (iii) detection of free SAs and sugar-bound SAs, and (iv) preparation of SA-contaminated honey. Thus, the efficiency of different hydrolysis conditions was assessed by comparing the bound SA content before and after hydrolysis. In addition, optimization of the sample pretreatment procedures and LC conditions to minimize matrix effects by separation from significant matrix interferences was also performed. Satisfactory results in terms of hydrolysis efficiency (approximately 88.3%-99.2%), extraction efficiency (84.2%-105.3%), recovery (95.9%-103.1%), and limit of quantification (0.6-1.5 μg·kg^-1) were obtained.

A rapid multiclass method for antibiotic residues in goat dairy products by UPLC-quadrupole/electrostatic field orbitrap high-resolution mass spectrometry

Background

Sulfanilamides, quinolones, nitroimidazoles, tetracyclines, cephalosporins, macrolides, and β-lactam are common tools in agriculture and can be found in animal-based foods such as goat milk and goat dried milk. To evaluate the risk of these species, reliable analytical methods are needed for accurate concentration determination, especially in goat milk and goat dried milk.

Method

We describe a method based on PRiME extraction coupled with UPLC-quadrupole/electrostatic field orbitrap high-resolution mass spectrometry to accomplish this task.

Result

Under optimal conditions, the limit of quantification for all antibiotics was 0.5–100 μg/L in goat milk and goat dried milk samples. The recoveries were 60.6–110.0% for goat milk and 60.1–109.6% for goat dried milk with a coefficient of variation less than 15%. The detection limits were 0.5–1.0 μg/kg. The limits of quantification for the analytes were 5.0–10.0 μg/kg. Finally, the method was used to screen veterinary antibiotics in 50 local goat milk and goat dried milk samples; metronidazole and enrofloxacin were detected in goat milk.

Conclusion

This method offers good reliability and the capacity for simultaneous detection can be used to detect residual contents and evaluate health risks in goat milk and goat dried milk.

Signal enhancement in supercritical fluid chromatography-diode-array detection with multiple injection

To circumvent the detrimental effects of large‐volume injection with fixed‐loop injector in modern supercritical fluid chromatography, the feasibility of performing multiple injection was investigated. By accumulating analytes from a certain number of continual small‐volume injections, compounds can be concentrated on the column head, and this leads to signal enhancement compared with a single injection. The signal to noise enhancement of different compounds appeared to be associated with their retention on different stationary phases and with type of sample diluent. The diethylamine column gave the best signal to noise enhancement when acetonitrile was used as sample diluent and the 2‐picolylamine column showed the best overall performance with water as the sample diluent. The advantage of multiple injection over one‐time large‐volume injection was proven with sulfanilamide, with both acetonitrile and water as sample diluents. The multiple injection approach exhibited comparable within‐ and between‐day precision of retention time and peak area with those of single injections. The potential of the multiple injection approach was demonstrated in the analysis of sulfanilamide‐spiked honey extract and diclofenac‐spiked ground water sample. The limitations of this approach were also discussed.

Simultaneous determination of sulfonamides and fluoroquinolones from environmental water based on magnetic double-template molecularly imprinting technique

In this work, a fast and selective method based on magnetic extraction is presented for the simultaneous extraction of sulfonamides (SAs) and fluoroquinolones (FQs), followed by liquid chromatography-tandem mass spectrometry detection. In this method, magnetic surface double-template molecularly imprinted polymers (MSdt-MIPs) with superparamagnetic property and high selectivity toward both SAs and FQs were synthesized and directly applied to the simultaneous extraction of SAs and FQs from environmental water as magnetic adsorbents. The extraction and enrichment procedures could be accomplished in one single step by stirring the mixture of MSdt-MIPs and water sample, and the MSdt-MIPs with adsorbed analytes were easily separated from the water sample by a magnet afterwards. The adsorption mechanism of MSdt-MIPs was investigated by employing the adsorption thermodynamic and kinetic studies, and the selectivity of the MSdt-MIPs toward target analytes was evaluated through the selectivity test. For validation of the proposed method, the matrix effect was evaluated and compared to that of the traditional SPE method. Excellent linearity (R > 0.9990) for both SAs and FQs were obtained in the concentration range of 20-2000 ng L^-1, and the limits of detection are in the range of 3.0-4.7 ng L^-1 for SAs while 4.1-6.1 ng L^-1 for FQs. Finally, the proposed method was successfully applied to the simultaneous determination of SAs and FQs in several environmental water samples.

Sulfonated poly(styrene-divinylbenzene) modified with amines and the application for pipette-tip solid-phase extraction of carbendazim in apples

Sulfonated poly(styrene-divinylbenzene) modified with five kinds of amine functional groups was applied to the determination of carbendazim in apple samples with a pipette-tip solid-phase extraction method. The structures of the polymers were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Five different modifications of the solid-phase extraction sorbent based on sulfonated poly(styrene-divinylbenzene) were tested under static and pipette-tip solid-phase extraction conditions. The polymer modified with p-methoxyaniline showed the best recognition capacity and adsorption amount for carbendazim. Under the optimum conditions, 3.00 mg of the adsorbent, 1.00 mL of ethyl acetate as washing solvent, and 1.00 mL of ammonia/acetonitrile (5:95, v/v) as elution solvent were used in the pretreatment procedure of apple samples. The calibration graphs of carbendazim in methanol were linear over 5.00-200.00 μg/mL, and the limits of detection and quantification were 0.01 and 0.03 μg/mL, respectively. The method recoveries of carbendazim were in the range of 91.31-98.13% with associated intraday relative standard deviations of 0.76-2.13% and interday relative standard deviations of 1.10-1.85%. Sulfonated poly(styrene-divinylbenzene) modified with p-methoxyaniline showed satisfactory results (recovery: 97.96%) and potential for the rapid purification of carbendazim in apple samples combined with the pipette-tip solid-phase extraction.

Design for the transfer of a validated liquid chromatography/tandem mass spectrometry analytical method for the determination of antimicrobial residues in honey from low-resolution to high-resolution mass spectrometry

RATIONALE

This paper investigates the validity of the transfer of a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the determination of veterinary medicinal products in honey and compares it with an LC/linear ion trap/Orbitrap mass spectrometry method. A descriptive statistical approach was used in order to assess whether such a transfer would succeed or fail. This approach is based on the simultaneous evaluation of the trueness and of the intermediate precision for each compound at a 95% interval of confidence of both analytical techniques.

METHODS

Two grams of honey were placed in a centrifuge tube and diluted with 2.5 mL of ultra-pure water and 2.5 mL of acidified methanol with hydrochloric acid at 2 mol.mL^-1 . The extract was purified with 50 mg of primary secondary amine and then analyzed using LC/MS/MS in multiple reaction monitoring (MRM) mode and LC/orbitrap high-resolution mass spectrometry in full scan mode. Both analytical techniques were compared by using the descriptive statistical approach for the determination of antimicrobial residues in honey.

RESULTS

The transfer of the method showed that the Orbitrap system provides the same accurate analytical results compared with the LC/MS/MS method except for 4-epitetracycline, anhydroerythromycin A, erythromycin A enol ether, and dihydrostreptomycin. Furthermore, the LC/LTQ-Orbitrap system is capable of successfully competing with the LC/MS/MS method by additional provision of high mass resolution and mass accuracy even though it shows less sensitivity compared with the LC/MS/MS instrument. CCα levels for most analytes were 1.3 times higher by LC/MS/MS than those observed by LC/LTQ-Orbitrap. The method was assessed in terms of relative bias through analysis of a reference material provided by FAPAS (Food Analysis Performance and Assessment Scheme) and also through the control of several contaminated honey samples from local Lebanese markets. Satisfactory relative bias was below 22% except for tetracycline found in one sample that showed a higher bias at 29%.

CONCLUSIONS

The LC/LTQ-Orbitrap method offers adequate performance in comparison with previously validated method on a LC/MS/MS system resulting in acceptance of the transfer of the method from LC/MS/MS to LC/LTQ-Orbitrap. Copyright © 2017 John Wiley & Sons, Ltd.

The exposure of honey bees (Apis mellifera; Hymenoptera: Apidae) to pesticides: Room for improvement in research

Losses of honey bees have been repeatedly reported from many places worldwide. The widespread use of synthetic pesticides has led to concerns regarding their environmental fate and their effects on pollinators. Based on a standardised review, we report the use of a wide variety of honey bee matrices and sampling methods in the scientific papers studying pesticide exposure. Matrices such as beeswax and beebread were very little analysed despite their capacities for long-term pesticide storage. Moreover, bioavailability and transfer between in-hive matrices were poorly understood and explored. Many pesticides were studied but interactions between molecules or with other stressors were lacking. Sampling methods, targeted matrices and units of measure should have been, to some extent, standardised between publications to ease comparison and cross checking. Data on honey bee exposure to pesticides would have also benefit from the use of commercial formulations in experiments instead of active ingredients, with a special assessment of co-formulants (quantitative exposure and effects). Finally, the air matrix within the colony must be explored in order to complete current knowledge on honey bee pesticide exposure.

Selective determination of sulfonamides from environmental water based on magnetic surface molecularly imprinting technology

In the study, a simple and selective method based on magnetic separation technology is presented for the extraction of sulfonamides (SAs) from environmental water, followed by liquid chromatography-tandem mass spectrometry. In this method, magnetic surface molecularly imprinted polymers (Fe₃O₄@SiO₂@MIPs) with super-paramagnetic property and high selectivity toward SAs were developed as magnetic adsorbents. The Fe₃O₄@SiO₂@MIPs were then applied to the selective extraction of SAs from environmental water. The extraction and enrichment were accomplished simultaneously in a single step by simply stirring the mixture of adsorbents and water samples. The Fe₃O₄@SiO₂@MIPs were characterized by scanning electron microscopy, Fourier-transform infrared spectrometry, and vibrating sample magnetometry. The adsorption thermodynamics and kinetics were employed to study the adsorption mechanism of the Fe₃O₄@SiO₂@MIPs. And the matrix effect of the method was evaluated. Calibration curves obtained by analyzing matrix-matched standards show excellent linear relationship (R = 0.9994-0.9999) in the concentration range of 10-1000 ng L^-1, and the limits of detection are in the range of 1.4-2.8 ng L^-1. The relative standard deviations of intra- and inter-day obtained are in the range of 2.8 to 7.8 and 3.1 to 7.9%, respectively. The proposed method was successfully applied to determine SAs in six environmental water samples, and SAs were detectable in four of them with the concentration from 10.5 to 120.2 ng L^-1.

Nontargeted Screening and Determination of Sulfonamides: A Dispersive Micro Solid-Phase Extraction Approach to the Analysis of Milk and Honey Samples Using Liquid Chromatography-High-Resolution Mass Spectrometry

A simple, rapid, sensitive, selective, and environmentally friendly method, based on a dispersive micro solid-phase extraction approach (dispersive micro SPE) coupled with liquid chromatography-high-resolution mass spectrometry (LC-HRMS), was established for the analysis of sulfonamides in honey and milk. An efficient nontargeted screening strategy was designed to discover and identify known and unknown sulfonamides in honey and milk using full-MS/all ion fragmentation (AIF) mass spectrometry acquisition mode. The experimental parameters and conditions of dispersive micro SPE on extraction efficiency were optimized in detail. Under the optimized conditions, the dispersive micro SPE method showed a low limit of detection (LOD) for the targeted sulfonamides ranging from 0.003 to 0.2 μg/L in milk and from 0.01 to 1 μg/kg in honey with the recoveries of the analytes between 68.8 and 115.8%. Compared with the reported methods, improvements in convenience, low cost, and environmental friendliness were obtained in this study.

Validation approach for a fast and simple targeted screening method for 75 antibiotics in meat and aquaculture products using LC-MS/MS

An approach is described to validate a fast and simple targeted screening method for antibiotic analysis in meat and aquaculture products by LC-MS/MS. The strategy of validation was applied for a panel of 75 antibiotics belonging to different families, i.e., penicillins, cephalosporins, sulfonamides, macrolides, quinolones and phenicols. The samples were extracted once with acetonitrile, concentrated by evaporation and injected into the LC-MS/MS system. The approach chosen for the validation was based on the Community Reference Laboratory (CRL) guidelines for the validation of screening qualitative methods. The aim of the validation was to prove sufficient sensitivity of the method to detect all the targeted antibiotics at the level of interest, generally the maximum residue limit (MRL). A robustness study was also performed to test the influence of different factors. The validation showed that the method is valid to detect and identify 73 antibiotics of the 75 antibiotics studied in meat and aquaculture products at the validation levels.

Headspace Microextraction of Sulfonamides from Honey by Hollow Fibers Coupled with Ultrasonic Nebulization

A new method for the rapid simultaneous determination of five sulfonamides in honey was developed using ultrasonic nebulization-assisted extraction coupled with hollow fiber liquid-liquid-liquid microextraction prior to liquid chromatography. In the present method, the sample solution was nebulized by ultrasonication. Sulfonamides in the aerosol particles were extracted by 1-octanol impregnated in the pores of a hollow fiber and further into the acceptor phase (acid solution, pH 2.0) contained in the lumen of the hollow fiber. Several experimental parameters that affect the extraction efficiency were optimized. The present method provides good recoveries (88.9-114.2%) and acceptable precision (<10.7%), indicating the effective extraction. The detection limits were 4.6-6.8 μg/kg, lower than the maximum residue limits of sulfonamides in honeys. Compared to the traditional extraction methods, the present method requires less organic solvent and operation time, demonstrating excellent cleanup ability and good enrichment efficiency.