Development of a rapid method for the determination of antibiotic residues in honey using UPLC-ESI-MS/MS

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.

Detection of Multiple Antibiotic Residues in Turkish Pine and Blossom Honeys Using LC-MS/MS Method

Due to the high demand for honey, beekeepers often feed the bees with antibiotics to protect honeybees against illnesses; the determination of veterinary drugs and their residues in bee products especially in honey is gaining importance. In this study, commercially available 15 different brands, a total of 22 honey (14 blossoms and 8 pines) samples obtained from 5 chain supermarkets in the city of Bingöl and Diyarbakır, Turkey were analysed for 29 antibiotic residues. These antibiotics belong to 10 different categories, including tetracyclines, aminoglycosides, macrolides, sulfonamides, fluoroquinolones, benzimidazoles, anthelmintic, amphenicols, quinolines, and oxazolidines. For the qualitative and quantitative determination of the antibiotics, a triple quadrupole liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used. A total of 10 out of 22 honey (8 blossom, 57.14 % and 2 pine, 25 %) samples were found to be positive for antibiotics. Among the tested antibiotics, tetracycline, dihydrostreptomycin, streptomycin, erythromycin, and sulfadimidine were detected in the honey samples. Dihydrostreptomycin and sulfadimidine were detected in 6 samples, erythromycin was determined in 4 samples, streptomycin was found in 2 samples, and lastly, tetracycline was detected only in one sample. The highest and the lowest concentrations of antibiotics detected in the samples were dihydrostreptomycin and erythromycin found at the amount of 992.58 μg/kg and 0.77 μg/kg respectively. The proposed method was validated with a limit of quantification (LOQ) and limit of detection (LOD) ranging between 0.42 and 3.22 μg /kg and 0.13-0.97 μg /kg respectively. Good linearities were also achieved ranging between R2 =0.987 and 0.999.

Multiresidues Multiclass Analytical Methods for Determination of Antibiotics in Animal Origin Food: A Critical Analysis

Veterinary drugs are widely used to prevent and treat diseases. The European Union has forbidden the use of antibiotics as growth promoters since 2006. Its abusive use leads to the presence of antibiotic residues (AR) in foods of animal origin which is associated with antibiotic resistance. The monitoring of AR in food intended for human consumption is of utmost importance to assure Food Safety. A systematic bibliographic review was carried out on the analytical methodologies, published in 2013, for the determination of AR in foods of animal origin. The food processing effect in the AR detected in animal products is also addressed. However, there is a preference for multiresidues multiclass methods, i.e., methodologies that allow determining simultaneously different classes of antibiotics, which is still a challenge for researchers. The wide diversity of physico-chemical properties of these drugs is an obstacle to achieving excellent analytical performance for a vast number of molecules analyzed concurrently. New techniques in sample preparation continue to be developed in order to obtain a compromise between good recoveries and extracts without interferences (clean extracts). The most widely used analytical methodology for the determination of AR is liquid chromatography coupled with mass spectrometry. However, the current trend is focused on the use of powerful high-resolution MS detectors such as Time of Flight and Orbitrap with modern chromatographic systems. Cooking time and temperature control are the key processing conditions influencing the reduction of AR in foods.

Enrichment of tetracycline residues from honey samples using carrier-mediated hollow fibre liquid-phase micro-extraction and quantification by LC-Q-TOF/MS

BACKGROUND

In this study, development and validation of a simple, miniaturized and, environmentally friendly carrier-mediated three-phase hollow-fibre liquid-phase micro-extraction (HFLPME) technique was investigated for the enrichment of tetracycline residues in honey samples. The extracts were analysed using UV-visible spectrophotometry and liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-TOF/MS). Parameters affecting the extraction efficiency of HFLPME such as pH of the donor and acceptor solutions, salt addition, agitation speed and extraction time were optimized.

RESULTS

The calibration curves showed good linearity, in the range of 1-100 μg kg^-1 with correlation coefficients ranging between 0.9943 and 0.9992, under the optimized conditions. Recoveries of blank honey samples at three spiking levels (1, 10 and 20 μg kg^-1 ) ranged from 81.2% to 107.5%. Relative standard deviations for the precision of the method were less than 15.0%. Limits of detection and limits of quantification were in the range of 0.0861-0.2628 μg kg^-1 and 0.2610-0.7964 μg kg^-1 , respectively. Finally, the proposed method was successfully applied in the extraction of five tetracyclines from honey samples. Doxycycline residue detected in one of the commercial honey samples was below the limit of quantification.

CONCLUSION

Because of the advantages offered by HFLPME, this method can be employed as an alternative to conventional extraction techniques for the clean-up and pre-concentration of antibiotics in complex matrices, including food samples. © 2021 Society of Chemical Industry.

Potential hepatoprotective effects of flavonoids contained in propolis from South Sulawesi against chemotherapy agents

The use of doxorubicin and epirubicin as chemotherapy agent causes side effects such as liver damage due to oxidative stress by reactive oxygen species (ROS) that cause increased of ALT and AST level as liver parameter. One source of natural antioxidants as ROS neutralizer comes from flavonoid that contain in propolis. Most researchers claim that flavonoid can be used to protect the liver. The aim of this study was to test the hepatoprotective effect of flavonoid in propolis from South Sulawesi against doxorubicin and epirubicin. The experiment included male Sprague dawley rats divided into nine groups. The rats received the microcapsule propolis or the quercetin orally for 15 days. The hepatotoxicity was promoted by injection epirubicin and doxorubicin (i.v.) with a cumulative dose of 9 mg/kg. In this study, total polyphenol and flavonoid tests of propolis have been carried out, there were 1.1% polyphenols and 2.7% flavonoids, the antioxidant activity tests showed IC50 value of 9849 ppm and LCMS/MS tests supported the presence of phenolic compounds in propolis from South Sulawesi. Liver parameter was measured and the results showed that the propolis 200 mg/kg group produced the lowest ALT and had potential protective effect against doxorubicin and epirubicin-induced hepatotoxicity.

Assessment of various veterinary drug residues in animal originated food products

The veterinary drugs are broad-spectrum antibacterial antibiotics; it uses to cure the animal disease. Many countries have banned veterinary drug residues like nitrofurans metabolites, chloramphenicol. However, the people were administrated veterinary drugs to animals as illegal to increase the milk production in animals for economic benefit. The results of illegally use of veterinary drugs remain as a residue in animal product like milk and it is very harmful to whom consume it cause cancer and allergic for human being which has entered the concern among milk consumers. To control illegal use of veterinary drugs, the government of India has restricted its use in animals. For the identification and confirmation of veterinary drug residues in animal products, analytical techniques such as liquid chromatography and mass spectrometry are available. These are very sophisticated equipments which are available nowadays and their methodologies for the analytical method validation are described by European commission 2002/657/EC. The use of veterinary drugs is a big challenge to effectively identify and authorization of their use. There are so many analytical techniques are using very effectively and taking very less time to protect the consumers from their adverse effects. These techniques take very less time to identify more groups of compounds such as tetracycline, sulfonamides, anthelmintic, and macrolides in single multi-residue method. These methods having validation parameters include system precision, calibration curve, accuracy, limit of detection, and quantification. Therefore, improvement in the existing technologies and accessibility of new screening methodologies will give opportunities for automation that helps in obtaining the results in very less time and improved sensitivity and specificity which contribute to better safety assurance, standard, and quality of various food products of animal origin.

Strontium tungstate-modified disposable strip for electrochemical detection of sulfadiazine in environmental samples

Rapid-monitoring of drugs has attracted tremendous consideration owing to robust global demand for cost-effective and high effectiveness. Binary metal oxides with various morphology have been reported as electrodes for electrochemical sensor to fulfilling the clinical and enviromental requirements. In this study, strontium tungstate (SrWO₄) nanoflakes have been successfully prepared via the facile sonochemical method for the first time. The characteristics of as-prepared SrWO₄ are systematically measured by various analytical and spectroscopic methods. The SrWO₄ nanoflakes are utilized to modify the electrochemical electrode for the sulfadiazine (SDZ) determination. The SrWO₄ modified electrode possesses excellent electrocatalytic activity and high recognition capability for the electrochemical detection of SDZ. Impressively, the as-fabricated SrWO₄ modified electrode attainted lowest oxidation peak at +0.93 V (vs Ag/AgCl₂) with the limit of detection of 0.009 μM, the sensitivity of 0.123 µA µM^-1 cm² and linear detection range of 0.05-235 μM. The enhanced performance of proposed SrWO₄-based sensors could be attributed to the catalytic effect, large surface area, good electrical conductivity and physicochemical nature. Notably, the electrocatalytic performances of the SDZ sensors are good as compared to the previous literature, indicating the significance of the newly designed SrWO₄ modified electrode. The real-sample diagnosis by the SDZ detection in environmental sample demonstrates the proposed SrWO₄-based sensors with good recovery range.

Determination of antibiotic residues in honey in relation to different potential sources and relevance for food inspection

Honey contaminations could derive from intensive agriculture and industrial activities, but also from beekeeper treatments. In EU no MRLs for antibiotics in honey are set, only a minimum required performance limit for chloramphenicol of 0.3 μg kg^-1 is recommended. Screening tests are available, characterised by their rapidity and simple use. Due to their high rate of false positives and the need to meet zero tolerance levels for antibiotics, their presence in samples was investigated using a liquid chromatography High Resolution Mass Spectrometry (LC-HRMS) multiclass antibiotic residue method, comparing the results with those of previous screening tests. The confirmatory method showed good sensitivity: CCα and CCβ ranging from 0.03 to 4.80 ng g^-1 and from 0.12 to 5.56 ng g^-1, respectively. Ninety-eight honey samples from different geographical areas, analysed by two screening tests, showed a high percentage of false positives. This is fundamental to guarantee honey safety, especially, for organic production.

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.

Direct injection high performance liquid chromatography coupled to data independent acquisition mass spectrometry for the screening of antibiotics in honey

The targeted analysis of veterinary drug residues in honey traditionally involves a series of extraction and purification steps prior to quantification with high performance liquid chromatography coupled to high resolution or tandem mass spectrometry. These steps, designed to separate the target analytes from interferences, are generally time-consuming and costly. In addition, traditional cleanup steps are likely to eliminate other compounds whose analysis could prove decisive in current or future assessment of the honey sample. Alternatively, direct injection without complex sample preparation steps has been introduced for the fast analysis of trace compounds in environmental and food matrices. The aim of this study was to develop a rapid method for the targeted analysis of 7 key veterinary drug residues in honey based on direct injection high performance liquid chromatography coupled to quadrupole time-of-flight, while simultaneously recording data-independent MS/MS (e.g. All Ions MS/MS data) for future re-examination of the data for other purposes. The new method allowed for the detection of the target residues at levels approximately 20-100 times lower than current regulatory limits, for a total analysis time of about 45 min. The recoveries (103-119%), the linearity (R ≥ 0.996) and the repeatability (RSD ≤ 7%) were satisfactory. The method was then applied to 35 honey samples from the Canadian market. Residues of tylosin A, tylosin B, sulfamethazine and sulfadimethoxine were detected in 6, 9, 6 and 23% of the samples respectively, at levels below the regulatory limits in Canada. The possibility of adding a hydrolysis step to study sulfonamides in honey was tested, which provided good results for this family of compounds but lead to degradation of some of the other analytes. Finally, the non-targeted identification of several compounds was demonstrated as a proof of concept of future re-examination of All Ions MS/MS data. This paper illustrates the capacity of this novel method to combine targeted and non-targeted screening of chemical residues in honey.

A genetically engineered Escherichia coli that senses and degrades tetracycline antibiotic residue

Due to the abuse of antibiotics, antibiotic residues can be detected in both natural environment and various industrial products, posing threat to the environment and human health. Here we describe the design and implementation of an engineered Escherichia coli capable of degrading tetracycline (Tc)-one of the commonly used antibiotics once on humans and now on poultry, cattle and fisheries. A Tc-degrading enzyme, TetX, from the obligate anaerobe Bacteroides fragilis was cloned and recombinantly expressed in E. coli and fully characterized, including its K m and k cat value. We quantitatively evaluated its activity both in vitro and in vivo by UV-Vis spectrometer and LC-MS. Moreover, we used a tetracycline inducible amplification circuit including T7 RNA polymerase and its specific promoter PT7 to enhance the expression level of TetX, and studied the dose-response of TetX under different inducer concentrations. Since the deployment of genetically modified organisms (GMOs) outside laboratory brings about safety concerns, it is necessary to explore the possibility of integrating a kill-switch. Toxin-Antitoxin (TA) systems were used to construct a mutually dependent host-plasmid platform and biocontainment systems in various academic and industrious situations. We selected nine TA systems from various bacteria strains and measured the toxicity of toxins (T) and the detoxifying activity of cognate antitoxins (A) to validate their potential to be used to build a kill-switch. These results prove the possibility of using engineered microorganisms to tackle antibiotic residues in environment efficiently and safely.

Investigating nanohybrid material based on 3D CNTs@Cu nanoparticle composite and imprinted polymer for highly selective detection of chloramphenicol

Nanotechnology holds great promise for the fabrication of versatile materials that can be used as sensor platforms for the highly selective detection of analytes. In this research article we report a new nanohybrid material, where 3D imprinted nanostructures are constructed. First, copper nanoparticles are deposited on carbon nanotubes and then a hybrid structure is formed by coating molecularly imprinted polymer on 3D CNTs@Cu NPs; and a layer by layer assembly is achieved. SEM and AFM revealed the presence of Cu NPs (100-500nm) anchored along the whole length of CNTs, topped with imprinted layer. This material was applied to fabricate an electrochemical sensor to monitor a model veterinary drug, chloramphenicol. The high electron transfer ability and conductivity of the prepared material produced sensitive response, whereas, molecular imprinting produces selectivity towards drug detection. The sensor responses were found concentration dependent and the detection limit was calculated to be 10μM (S/N=3). Finally, we showed how changing the polymer composition, the extent of cross linking, and sensor layer thickness greatly affects the number of binding sites for the recognition of drug. This work paves the way to build variants of 3D imprinted materials for the detection of other kinds of biomolecules and antibiotics.