New reagent for trace determination of protein-bound metabolites of nitrofurans in shrimp using liquid chromatography with diode array detector

Fast screening method to determine metabolites of nitrofurans in chicken meat using partitioned dispersive liquid-liquid microextraction combined with HPLC/DAD

Methods have been developed for the hydrolysis and derivatisation of protein-bound metabolites of nitrofurans and for the extraction of 2-nitrobenzaldehyde derivatives of the metabolites from chicken meat. In this work, the time needed for hydrolysis and derivatisation was reduced from the conventional 16 h to 90 min. Based on partitioned dispersed liquid-liquid microextraction, a method for extracting 2-nitrobenzaldehyde derivatives of metabolites from crude chicken meat has been developed. Under the optimised experimental conditions, enrichment factors (EFs) ranging from 92.8 to 208.9 were obtained. The method was linear over the range of 10-600 µg kg^-1 with determination coefficients (r²) between 0.9979 and 0.9996. Intraday and interday repeatability expressed as a percentage RSD, ranged from 2.2% to 11.2%, and 2.7% to 12.4%, respectively. LOD of 1.07-2.25 µg kg^-1 and LOQ of 3.09-6.2 µg kg^-1 were obtained. The proposed method was applied in the analysis of metabolites of nitrofurans in chicken meat obtained from farmers using them for their domestic consumption and proved free of the analytes. A recovery of 85.2-109.4% with a %RSD ranging between 3.4% and 13.7% was obtained at three spiking levels. The proposed method was successfully further applied for the analysis of target analytes in chicken meat samples purchased from different supermarkets around Roodeport, Gauteng (South Africa). There was no target analyte detected in the analysed samples. Therefore, the developed methods can be used for monitoring the corresponding metabolites of nitrofurans in chicken meat.

Determination of Antibiotic Residues in Aquaculture Products by Liquid Chromatography Tandem Mass Spectrometry: Recent Trends and Developments from 2010 to 2020

The issue of antibiotic residues in aquaculture products has aroused much concern over the last decade. The residues can remain in food and enter the human body through the food chain, posing great risks to public health. For the safety of foods and products, many countries have issued maximum residue limits and banned lists for antibiotics in aquaculture products. Liquid chromatography tandem mass spectrometry (LC/MS/MS) has been widely used for the determination of trace antibiotic residues due to its high sensitivity, selectivity and throughput. However, considering its matrix effects during quantitative measurements, it has high requirements for sample pre-treatment, instrument parameters and quantitative method. This review summarized the application of LC/MS/MS in the detection of antibiotic residues in aquaculture products in the past decade (from 2010 to 2020), including sample pre-treatment techniques such as hydrolysis, derivatization, extraction and purification, mass spectrometry techniques such as triple quadrupole mass spectrometry and high-resolution mass spectrometry as well as status of matrix certified reference materials (CRMs) and matrix effect.

Highly sensitive SERS detection of residual nitrofurantoin and 1-amino-hydantoin in aquatic products and feeds

Nitrofurantoin (NFT), a typical highly effective nitrofuran antibiotic drug, has been prohibited but still widely found in animal food products. It can be metabolized in animals to form 1-amino-hydantoin (AHD) that can then form stable and toxic metabolite-protein adducts. Hence, the detection of NFT and AHD in aquatic products and feeds is very important. However, there are limited reports concerning NFT detection and none about AHD by using surface-enhanced Raman spectroscopy (SERS) method. Herein, potassium bromide (KBr) decorated silver (Ag) nanoparticles (Ag-BrNPs)-based SERS approach was proposed for NFT and AHD detection. The limit of detection (LOD) for NFT was 1 μg/L. The detection of NFT residues in sea cucumber and fish feeds was also realized with the LOD of 1 and 50 ng/g, respectively. More importantly, the sensing of AHD was easily realized with the SERS approach for the first time. After the derivatization with 2-nitrobenzaldehyde (2-NBA), Ag-BrNPs were also successfully utilized for AHD detection in sea cucumber with the LOD of 5 ng/g.

Determination of nitrofuran metabolites in honey using a new derivatization reagent, magnetic solid-phase extraction and LC-MS/MS

In this study, 5-nitro-2-furaldehyde (5-NFA) was proposed as a new derivatizing agent for nitrofuran metabolites. It reacts with nitrofuran metabolites producing the parent nitrofurans (furazolidone, furaltadone, nitrofurantoin, and nitrofurazone). Magnetic hypercrosslinked polystyrene (HCP/Fe₃O₄) was first used for magnetic solid phase extraction (MSPE) clean-up before the determination of nitrofuran metabolite derivatives in honey via LC-MS/MS. Main parameters affecting the derivatization and MSPE efficiency were investigated in detail and the optimal conditions were found. The method was validated using honey spiked with the four metabolites at 1, 2 and 200 μg kg^-1. Recoveries of >85% were achieved for the all analytes. The matrix calibration curve was fitted with the correlation coefficient (R²) > 0.99 in the range of 1-200 μg kg^-1. Precision values expressed as relative standard deviation (RSD) were <12% and <15% for intra-day and inter-day precision, respectively. The limits of detection (LODs) for the nitrofuran metabolites were of 0.1-0.3 μg kg^-1 and the limits of quantitation (LOQs) were of 0.3-1.0 μg kg^-1. The proposed LC-MS/MS method was applied to the analysis of real honey samples.

Determination of Nitrofuran Metabolites in Fish by Ultraperformance Liquid Chromatography-Photodiode Array Detection with Thermostatic Ultrasound-Assisted Derivatization

Nitrofuran (NF) is a class of broad-spectrum antibiotics that are used illegally in animal feeding. NF and its metabolites have proven to pose potential risk to human health. To address the current analytical needs to quantify low levels of NF metabolites in animal foods, a sensitive method was developed for simultaneous detection of four NF metabolites in fish products by an ultraperformance liquid chromatography-diode array detector (UPLC-DAD). With 2-nitrobenzaldehyde (2-NBA) as the derivatizing reagent, the metabolites were hydrolyzed and derivatized under the assistance of thermostatic ultrasound. Compared with the current detection methods, the time of the derivatization reaction has been shortened from 16 to 2 h. The relative coefficient of four NF metabolite derivatives reached more than 0.998, with excellent linear relationship. The limits of detection (LODs) and limits of quantification (LOQs) of six repeated determinations reached 0.25-0.33 and 0.80-1.10 μg/kg, respectively. For all four NF metabolites, the limit of detection of the method was below the minimum required performance limit (MRPL) of 1.0 μg/kg, which makes it compatible with the EU requirements. The recoveries ranging from 89.8 to 101.9% with relative standard deviation below 6.5% were obtained for all of the NF metabolites. What's more, this method was successfully applied for the determination of four NF metabolites in the fish products. As a promising approach, this method could also be extended for the quantitation of NF metabolites in aquaculture and poultry products.

Determination of nitrofuran metabolites in marine products by high performance liquid chromatography–fluorescence detection with microwave-assisted derivatization

A sensitive method for simultaneous detection of four nitrofuran metabolites (3-amino-2-oxazolidinone (AOZ), semicarbazide (SEM), 3-amino-morpholinomethyl-2-oxazolidinone (AMOZ) and 1-aminohydantoin (AH)) in marine products.

Chemiluminescence determination of furazolidone in poultry tissues and water samples after selective solid phase microextraction using magnetic molecularly imprinted polymers

For the first time, a selective extraction method combined with chemiluminescence was developed for the determination of FZD in various samples.

Recent Advances in the Synthesis of Hydantoins: The State of the Art of a Valuable Scaffold

The review highlights the hydantoin syntheses presented from the point of view of the preparation methods. Novel synthetic routes to various hydantoin structures, the advances brought to the classical methods in the aim of producing more sustainable and environmentally friendly procedures for the preparation of these biomolecules, and a critical comparison of the different synthetic approaches developed in the last twelve years are also described. The review is composed of 95 schemes, 8 figures and 528 references for the last 12 years and includes the description of the hydantoin-based marketed drugs and clinical candidates.

Chromatographic detection of nitrofurans in foods of animal origin

Nitrofurans are antibacterials banned in livestock by different countries due to its relationship with the production of carcinogenic metabolites. Several studies have been conducted to find the best methodology to identify these residues. Te objectives of this review work were to show the risk of nitrofuran metabolites (furazolidone; nitrofurazone; nitrofurantoin, furaltadone and nifursol); to explain the application of liquid chromatography and mass spectrometry to determine the presence of these residues in foods of animal origin; and, finally, to report some methodologies that were recently used in different foods of animal origin.

Upgrading carbon dioxide by incorporation into heterocycles

Carbon dioxide is commonly regarded as the primary greenhouse gas, but from a synthetic standpoint can be utilized as an alternative and sustainable C1 synthon in organic synthesis rather than a waste. This results in the production of organic carbonates, carboxylic acids, and derivatives. Recently, CO2 has emerged as an appealing tool for heterocycle synthesis under mild conditions without using stoichiometric amounts of organometallic reducing reagents. This Minireview summarizes recent advances on methodologies for CO2 incorporation into N-, O-, and C-nucleophiles to provide various heterocycles, including cyclic carbamates, benzoxazine-2-one, 4-hydroxyquinolin-2-one, quinazoline-2,4(1 H,3 H)-diones, benzimidazolones, α-alkylidene cyclic carbonate.

Residue depletion of nifuroxazide in broiler chicken

BACKGROUND

Several nitrofuran drugs have been prohibited for use in food producing animals due to their carcinogenic and mutagenic effects. However, one of the nitrofurans, nifuroxazide, is still used as a veterinary drug in some countries. This study was conducted to investigate the residue depletion of nifuroxazide in broiler chicken. Chickens were fed with dietary feeds containing 50 mg kg⁻¹ of nifuroxazide for seven consecutive days. Liver, kidney, muscle and plasma samples were collected at different withdrawal periods, and the residues of parent nifuroxazide and its acid-hydrolysable side chain, 4-hydroxybenzhydrazide (HBH), in these samples were determined.

RESULTS

Nifuroxazide was metabolised in vivo and its metabolite HBH was formed. Parent nifuroxazide was not detectable in these samples after 14 days of cessation. HBH was detectable in these samples even after 28 days of cessation and the total HBH residues were higher than 1.0 ng g⁻¹. Furthermore, the residue level of tissue bound HBH was much higher than that of free HBH.

CONCLUSION

The tissue-bound HBH could be used as a marker to monitor the residue of nifuroxazide in chicken and the best target tissue should be liver. This is the first paper reporting the residue depletion of nifuroxazide in chicken.

Residue depletion of nitrovin in chicken after oral administration

In this study, the residue depletion of nitrovin in chicken was studied after feeding the birds with dietary feeds containing 10 mg/kg of nitrovin for 7 consecutive days. Tissues (muscle, fat, kidney, and liver) and plasma were collected at different withdrawal periods and determined by a high-performance liquid chromatography-ultraviolet (HPLC-UV) method. The limit of detection for nitrovin in tissue and plasma samples was 0.1 ng/(g or mL), and the inter- and intrarecoveries from the blank fortified samples were in the range of 71.1-85.7%. At the withdrawal period of 0 days, the residue concentration of nitrovin in plasma was the highest (average of 84.98 ng/mL) compared to those in muscle, fat, liver, and kidney (average of 21.04, 61.18, 24.04, and 68.28 ng/g, respectively). At the withdrawal period of 28 days, the residue levels of nitrovin in muscle, fat, liver, and plasma were all higher than 1.0 ng/(g or mL) and the highest concentration was in liver (average of 5.8 ng/g). These data are in support of the ban of nitrovin as a feed additive in food-producing animals.