Liquid chromatography-tandem mass spectrometry for the determination of protein-bound residues in shrimp dosed with nitrofurans

Facile engineering of gadolinium cobaltite anchored on functionalized carbon black as dynamic electrocatalyst for ultra-sensitive detection of nitroaromatic drug

There has been a significant increase in the production and use of antibiotic drugs. However, the overuse and improper disposal of nitro-based antibiotics pose a significant threat to human health and the ecosystem. Specifically, the residues of antibiotic drugs such as nitrofurantoin (NFT) are dangerous to public health and pose a threat to the environment. In this study, we prepared a novel nanocomposite consisting of gadolinium cobaltite embedded functionalized carbon black (GdCoO3/f-CB) via a simple hydrothermal technique and utilized this nanocomposite as an electrode material for the electrochemical detection of NFT. The structural and morphological properties of the GdCoO3/f-CB nanocomposite was analyzed using a range of techniques, including XRD, Raman, XPS, EDX-Mapping, and HR-TEM. The electrocatalytic activity of the GdCoO3/f-CB nanocomposite was investigated using both CV and DPV techniques for the detection of NFT. Our results demonstrated that the prepared GdCoO3/f-CB nanocomposite delivered the excellent activities toward the detection of NFT at an extremely low limit of detection (LOD) of 2 nM and exhibited high sensitivity of 31 μA·μM-1·cm-2. Additionally, the proposed NFT sensor using GdCoO3/f-CB nanocomposite provided excellent reproducibility, repeatability, and selectivity, even in the presence of interfering molecules such as metal ions, biomolecules, and similar nitro compounds. These findings suggest that the GdCoO3/f-CB nanocomposite provides significant potential for the electrochemical detection of antibiotic drug residues for public health and the environment.

One-step synthesis of blue emission copper nanoclusters for the detection of furaltadone and temperature

Polyvinyl pyrrolidone (PVP), playing roles as a templating agent, can be applied to prepare blue-emitting copper nanoclusters (Cu NCs@PVP) on the basis of a rapid chemical reduction synthesis method. The Cu NCs@PVP displayed a blue emission wavelength at 430 nm and the corresponding quantum yield (QY) could reach 10.4%. Subsequently, the as-synthesized Cu NCs@PVP were used for the trace analysis of furaltadone based on the inner filter effect (IFE) between Cu NCs@PVP and furaltadone, which caused the fluorescence to be effectively quenched. Additionally, this proposed determination platform based on the Cu NCs@PVP for furaltadone sensing possessed an excellent linear range from 0.5 to 100 μM with a lower detection limit of 0.045 μM (S/N = 3). Meanwhile, the Cu NCs@PVP also could be applied for the sensing of temperature. Furthermore, the practicability of the sensing platform has been successfully verified by measuring furaltadone in real samples, affirming its potential to increase fields for the determination of furaltadone.

Determination of Nitrofuran Metabolites in Complex Food Matrices Using a Rough, Cheap, Easy-Made Wooden-Tip-Based Solid-Phase Microextraction Probe and LC-MS/MS

In this study, a rough, cheap, easy-made wooden-tip-based solid-phase microextraction (SPME) probe was first developed for simultaneous determination of 4 nitrofuran metabolite derivatives in complex food matrices via LC-MS/MS. A simple dip-coating method was used to coat wooden tips with biocompatible polyacrylonitrile (PAN) and N-vinylpyrrolidone-co-divinylbenzene, also known as HLB particles, which served as the extractive substrate in the proposed device. Compared with the traditional solid-phase extraction (SPE) method, the proposed device shortens sample clean-up time, reduces solvent consumption, and decreases testing costs. In addition, the main parameters affecting the SPME procedure efficiency were investigated in detail and the optimal conditions were found. The method was validated using three different food matrixes (pork, croaker, and honey) by spiking with the four metabolites at 0.5, 1.0, and 5.0 μg/kg, as well as their internal standards. The average recovery of all nitrofuran metabolite derivatives ranges from 97.4–109.5% (pork), 87.5–112.7% (croaker), and 98.6–109.0% (honey). Relative standard deviations were all <10% for intraday and interday precision. The values of limit of detection and limit of quantification were, respectively, ranging from 0.011 to 0.123 and 0.033 to 0.369 μg/kg (pork), 0.009 to 0.112 and 0.027 to 0.339 μg/kg (croaker), and 0.010 to 0.131 and 0.030 to 0.293 μg/kg (honey). The presented method was applied to the analysis of real positive samples.

Investigation of electrocatalytic and photocatalytic ability of Cu/Ni/TiO2/MWCNTs Nanocomposites for detection and degradation of antibiotic drug Furaltadone

In this manuscript, "Get two mangoes with one stone" strategy was used to study the electrochemical detection and photocatalytic mineralization of furaltadone (FLT) drug using Cu/Ni/TiO2/MWCNTs nanocomposites for the first time. The bi-functional nanocomposites were synthesized through a hydrothermal synthesis technique. The successfully synthesized nanocomposites were analyzed by various analytical techniques. The Cu/Ni/TiO2/MWCNTs nanocomposites decorated screen-printed carbon electrode (SPCE) exhibit a good electrocatalytic ability towards detection of FLT. Moreover, the electrocatalytic detection of FLT based on the nanocomposites decorated SPCE have high stability, lower detection limit, and excellent sensitivity of 0.0949 μM and 1.9288 μA μM-1 cm-2, respectively. In addition, the nanocomposites decorated SPCE electrodes performed in real samples, such as river water and tap water, the satisfactory results were observed. As UV-Visible spectroscopy revealed that the Cu/Ni/TiO2/MWCNTs nanocomposites had an excellent photocatalytic ability for degradation of FLT drug. The higher degradation efficiency of 75% was achieved within 45 min under irradiation of visible light. In addition, after the degradation process various intermediates are produced which is confirmed by GC-MS analysis. The excellent photocatalytic ability was improved to the dopant ions and restrictions of electron-hole pair.

Determination of Chloramphenicol and Nitrofuran Metabolites in Cobia, Croaker, and Shrimp Using Microwave-Assisted Derivatization, Automated SPE, and LC-MS/MS-Results from a U.S. Food and Drug Administration Level Three Inter-Laboratory Study

BACKGROUND

An interlaboratory study was conducted to test a published, peer-reviewed manuscript in the Journal of AOAC INTERNATIONAL Vol 98, No. 3, 2015, "Quantitation of Chloramphenicol and Nitrofuran Metabolites in Aquaculture Products Using Microwave-Assisted Derivatization, Automated Solid-Phase Extraction, and LC-MS/MS."

OBJECTIVE

The purpose of this study was to demonstrate the performance of the method in shrimp, cobia, and croaker matrices.

METHOD

Three U.S. Food and Drug Administration laboratories participated in the collaborative study. The laboratories tested matrix blanks and laboratory-fortified matrix blanks at various levels in three separate matrices. The method evaluation included determination of the LOQ, accuracy, and precision.

RESULTS

The reproducibility and repeatability of the RSD, % levels for matrix spikes fortified below the action level were < 10% for all residues in shrimp, < 13% for all residues in cobia except for 3-amino-2-oxazolidinone which was ≤ 22%, and < 16% for croaker. The RSD, % levels for all other spikes in the study were < 14%. Average percent recoveries for all matrices ranged from 81.6% - 102%.

CONCLUSIONS

The study demonstrated that the method is acceptable for use for the combined determination of chloramphenicol and nitrofuran metabolites in the study matrices.

HIGHLIGHTS

The study showed acceptable quantitation for the high-throughput chloramphenicol and nitrofuran metabolites method.

Semicarbazide Accumulation, Distribution and Chemical Forms in Scallop (Chlamys farreri) after Seawater Exposure

Simple Summary

Semicarbazide is considered the characteristic metabolite of nitrofurazone and it is often used as a marker to monitor the illegal use of nitrofurazone in foods. Recent studies have indicated that semicarbazide pollution can be introduced in many ways and this compound is a newly recognized pollutant type in the environment that accumulates in aquatic organisms throughout the food chain. Scallops are the third most consumed shellfish in China. We therefore studied the accumulation, chemical forms, and distribution of semicarbazide in scallop tissues. Semicarbazide added to tank seawater resulted in its accumulation in both free and tissue-bound forms and the levels varied according to tissue and were present in all tissues examined. The levels were highest in viscera and the lowest in muscle. The levels of semicarbazide in the environment and in cultured shellfish should be monitored to ensure food quality and safety and human health.

Abstract

Semicarbazide is a newly recognized marine pollutant and has the potential to threaten marine shellfish, the ecological equilibrium and human health. In this study, we examined the accumulation, distribution, and chemical forms of semicarbazide in scallop tissues after exposure to 10, 100, and 1000 μg/L for 30 d at 10 °C. We found a positive correlation between semicarbazide residues in the scallops and the exposure concentration (p < 0.01). Semicarbazide existed primarily in free form in all tissues while bound semicarbazide ranged from 12.1 to 32.7% and was tissue-dependent. The time for semicarbazide to reach steady-state enrichment was 25 days and the highest levels were found in the disgestive gland, followed by gills while levels in gonads and mantle were similar and were lowest in adductor muscle. The bioconcentration factor (BCF) of semicarbazide at low exposure concentrations was higher than that at high exposure concentrations. These results indicated that the scallop can uptake semicarbazide from seawater and this affects the quality and safety of these types of products when used as a food source.

Development and Validation of a LC-MS/MS Method for the Determination of Nitrofuran Metabolites in Soft-Shell Turtle Powder Health Food Supplement

Soft-shell turtle (SST; freshwater terrapin or tortoise) is a popular and important health functional food (HFF) product in many Asian countries. HFFs containing SST must be safe, but several HFFs have been found to be contaminated with dangerous substances, such as nitrofuran metabolites (NFMs). This finding suggests that the consumption of HFFs results in the regular exposure of vulnerable individuals to hazardous substances. Importantly, nitrofuran antibiotics have been banned for use in food-producing animals since the 1990s by the European Union. Thus, in this study, we propose a reliable and quick method to reduce the time required for the detection of four NFMs in SST powder that conventional methods are unable to quantify. Our method involves the derivatization and hydrolysis of SST powder and was validated in accordance with the requirements of European Commission Decision 2002/657/EC. The method achieves an apparent mean recovery of 82.2–108.1%, repeatability of 1.5–3.8%, and reproducibility of 2.2–4.8% for 0.5–10.0 μg kg⁻¹ of 1-aminohydantoin, semicarbazide, 3-amino-2-oxazolidinone, and 3-amino-5-morpholinomethyl-2-oxazolidinone. In addition, linearity was achieved with correlation coefficients of 0.999, and the detection capability (CCβ) and decision limit (CCα) were found to be reliable, indicating that this is a fast and accurate method for the analysis of SST powder. The validated method was successfully applied to detect NFMs in SST powder in commercial HHFs.

A simplified modification to rapidly determine the residues of nitrofurans and their metabolites in aquatic animals by HPLC triple quadrupole mass spectrometry

A simplified method is described for reducing the analysis time of nitrofurans (NFs) and nitrofuran metabolites (NFMs) in the aquatic animals. Most existing HPLC-MS/MS methods are intended only for NFMs and are based on their fast metabolic transformations. We optimized a method for simultaneously detecting major NFs and their metabolites, including nitrovin (NV) that imply use of an optimized buffer solution. The novel method was validated by six different aquatic animal matrices (loach, catfish, shrimp, lobster, scallop, and eel) spiked with the analytes at 0.5, 1.0, and 2.0 μg kg^-1. Recovery rates and %RSDs (relative standard deviations) of 82-97% and 1-8% were observed for NFMs, respectively, with values of 70-96% and 1-8% obtained for furazolidone, furaltadone, nitrofurazone, nitrofurantoin, and NV, respectively. Linearity was observed in the 0.1-20 μg L^-1 range, with correlation coefficients greater than 0.99 recorded for all compounds. The developed method is sensitive, accurate, easier to use, and faster than previous methods when applied to real samples. To the best of our knowledge, this is the first method that can simultaneously determine NFs and their metabolites, as well as NV, using a single-step extraction process.

Complete validation according to current international criteria of a confirmatory quantitative method for the determination of nitrofuran metabolites in seafood by liquid chromatography isotope dilution tandem mass spectrometry

Despite the ban of nitrofurans (NFs) for use in food production in many countries in the 1990s, NF metabolites in food are still regularly detected during import control testing. We have developed a confirmatory routine method for the detection and quantification of NF metabolites in seafood using LC-MS/MS and validated the method according to the strict criteria in European legislation and Codex Alimentarius. Method characteristics were found to fulfill the criteria. We report for the first time a new false positive for 1-amino-2,4-imidazolidinedione (AHD), the metabolite of Nitrofurantoin (NFT). By using optimized washing procedures, the non tissue bound false positives can be minimized. The results from the validation on both lean and fatty fish and crustaceans, results from proficiency tests and routine use over many years, demonstrates that the method is fit for purpose to determine NF metabolites in the seafood category.

Plant Uptake and Metabolism of Nitrofuran Antibiotics in Spring Onion Grown in Nitrofuran-Contaminated Soil

Environmental pollution caused by the discharge of mutagenic and carcinogenic nitrofurans to the aquatic and soil environment is an emerging public health concern because of the potential in producing drug-resistant microbes and being uptaken by food crops. Using liquid chromatography-tandem mass spectrometry analysis and with spring onion (Allium wakegi Araki) as the plant model, we investigated in this study the plant uptake and accumulation of nitrofuran from a contaminated environment. Our study revealed for the first time high uptake and accumulation rates of nitrofuran in the edible parts of the food crop. Furthermore, results indicated highly efficient plant metabolism of the absorbed nitrofuran within the plant, leading to the formation of genotoxic hydrazine-containing metabolites. The results from this study may disclose a previously unidentified human exposure pathway through contaminated food crops.

Automated In-Injector Derivatization Combined with High-Performance Liquid Chromatography-Fluorescence Detection for the Determination of Semicarbazide in Fish and Bread Samples

Semicarbazide (1) is a widespread genotoxic food contaminant originating as a metabolic byproduct of the antibiotic nitrofurazone used in fish farming or as a thermal degradation product of the common flour additive azodicarbonamide. The goal of this study is to develop a simple and sensitive high-performance liquid chromatography coupled with fluorescence detection (HPLC-FLD) method for the detection of compound 1 in food products. In comparison to existing methods for the determination of compound 1, the reported method combining online precolumn derivatization and HPLC-FLD is less labor-intensive, produces higher sample throughput, and does not require the use of expensive analytical instruments. After validation of accuracy and precision, this method was applied to determine the amount of compound 1 in fish and bread samples. Comparative studies using an established liquid chromatography coupled with tandem mass spectrometry method did not yield systematically different results, indicating that the developed HPLC-FLD method is accurate and suitable for the determination of compound 1 in fish and bread samples.

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.

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.

Multiresidue analysis of antibiotics in food of animal origin using liquid chromatography-mass spectrometry

Antibiotics are the most important drugs administered in veterinary medicine. Their use in food-producing animals may result in antibiotic residues in edible tissues, which are monitored to protect human and animal health, support the enforcement of regulations, provide toxicological assessment data, and resolve international trade issues. This chapter provides basic characterization of the most important classes of antibiotics used in food-producing animals (aminoglycosides, amphenicols, β-lactams, macrolides and lincosamides, nitrofurans, quinolones, sulfonamides, and tetracyclines), along with examples of practical liquid chromatographic-(tandem) mass spectrometric methods for analysis of their residues in food matrices of animal origin. The focus is on multiresidue methods that are favored by regulatory and other food testing laboratories for their ability to analyze residues of multiple compounds in a time- and cost-effective way.

Tissue depletion and concentration correlations between edible tissues and biological fluids of 3-amino-2-oxazolidinone in pigs fed with a furazolidone-medicated feed

Furazolidone has been prohibited for use in food animal production worldwide for its carcinogenicity and mutagenicity, but it is still illegally used in some farms because of its effectiveness and cheap price. Because of the food safety and economical concerns, it is necessary to find an efficient and low-cost way to monitor the misuse of furazolidone in food-producing animals. For this regard, the tissue depletion and tissue-biological fluid concentration correlations of 3-amino-2-oxazolidinone (AOZ), which is the marker residue of furazolidone, were studied in pigs. Pigs were dosed with 400 mg/kg of furazolidone in feed for 7 days and were sacrificed at the withdrawal time of 0.5, 7, 21, 35, 56, and 63 days. Muscle, liver, kidney, urine, and plasma were collected to detect the AOZ by a simplified indirect competitive enzyme-linked immunosorbent assay (ic-ELISA). Results showed that AOZ was widely distributed in pigs and eliminated slowly after the digestion of furazolidone. The half-lives of AOZ in the plasma, urine, liver, kidney, and muscle were 13.7, 14.7, 13.6, 13.6, and 15.0 days, respectively. Good correlations of the AOZ concentration were found between plasma and muscle, plasma and liver, urine and liver, and urine and kidney in the depletion period of 7-63 or 21-63 days, with correlation coefficients of more than 0.97 and p values less than 0.05. These correlations can provide a basis for a simple and economical way using plasma/urine to monitor the illegal use of furazolidone in pigs without slaughter.

Multidetermination of four nitrofurans in animal feeds by a sensitive and simple enzyme-linked immunosorbent assay

In this study, the polyclonal antibody against furazolidone was produced with furazolidone coupling to protein carriers by a diazotization method and glutaraldehyde reaction, respectively. The antibody obtained showed good specificity toward furazolidone and various cross-reactivity toward nitrofurantoin, nitrofurazone, and furaltadone. Then, an indirect competitive enzyme-linked immunosorbent assay (ELISA) based on the antibody was first developed for multidetermination of four nitrofurans in animal feeds. The limit of detection (LOD) of the method was 0.2-2.1 ng/g depending on the component. After simple extraction, the fortified swine and broiler chicken feed samples were detected with recovery ranges of 75.9-86.4%. Results obtained from ELISA were confirmed by high-performance liquid chromatography (HPLC) with ultraviolet detection. Analysis of the unknown feed samples indicates that ELISA can be a practical tool for screening of nitrofurans in animal feeds before confirmation by HPLC.

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

The synthesis of derivatives of metabolites from furazolidone, furaltadone, nitrofurazone, and nitrofurantoin using a new derivatizing reagent, 2-naphthaldehyde (NTA), is described. The reaction product was used in liquid chromatography with diode array detector (LC-DAD) for determination of protein-bound metabolites of nitrofurans in shrimp followed by two steps of liquid-liquid extraction. Derivatives of nitrofuran metabolites are well separated from NTA remaining in the extract upon separation on a ChromSpher 5 Pesticide (250 x 4.6 mm, 5 microm) column at 40 degrees C with acetonitrile/5 mM ammonium acetate adjusted to pH 7.5 gradient as the mobile phase and DAD detection at 308 nm except for naphthyl derivative of 1-aminohydantoin at 310 nm. The high absorptivity of these derivatives makes simultaneous screening of these metabolites in shrimp at 1 microg/kg possible for the first time using LC-DAD. The method was validated using blank shrimp fortified with all four metabolites at 1, 1.5, and 2 microg/kg. Recoveries were >86% with relative standard deviations of <14% for all four metabolites. Comparison between LC-DAD and APCI-MS/MS shows very good agreement for shrimp samples.

Residue depletion of nitrofuran drugs and their tissue-bound metabolites in channel catfish (Ictalurus punctatus) after oral dosing

The depletion of the nitrofuran drugs furazolidone, nitrofurazone, furaltadone, and nitrofurantoin and their tissue-bound metabolites [3-amino-2-oxazolidinone (AOZ), semicarbazide (SC), 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ), and 1-aminohydantoin (AH), respectively] were examined in the muscle of channel catfish following oral dosing (1 mg/kg body weight). Parent drugs were measurable in muscle within 2 h. Peak levels were found at 4 h for furazolidone (30.4 ng/g) and at 12 h for nitrofurazone, furaltadone, and nitrofurantoin (104, 35.2, and 9.8 ng/g respectively). Parent drugs were rapidly eliminated from muscle, and tissue concentrations fell below the limit of detection (1 ng/g) at 96 h. Peak levels of tissue-bound AMOZ and AOZ (46.8 and 33.7 ng/g respectively) were measured at 12 h, and of SC and AH (31.1 and 9.1 ng/g, respectively) at 24 h. Tissue-bound metabolites were measurable for up to 56 days postdose. These results support the use of tissue-bound metabolites as target analytes for monitoring nitrofuran drugs in channel catfish.

Analytical strategies to determine antibiotic residues in fish

The accelerated growth of aquaculture has resulted in a series of harmful effects to human health. The widespread and unrestricted use of antibiotics in this industry, to prevent bacterial infections, leads to remaining amounts in the aquatic environment. This has resulted in the emergence of antibiotic-resistant bacteria in aquaculture environments, in the increase in antibiotic resistance in fish pathogens as well as in the transfer of these resistance determinants to human pathogens. Moreover, the use of large amounts of antibiotics may lead to the presence of residual antibiotics in fish tissue and fish products. Fluoroquinolones, tetracyclines, penicillins, sulphonamides and other antibiotics, exhibiting activity against both Gram-positive and Gram-negative bacteria, are widely used for the treatment and prevention of diseases in fish. An extended and comprehensive review on the recent analytical methodologies concerning antibiotic residues in fish reported in the literature is provided in the present article. Emphasis is given on sample preparation regarding isolation and purification, chromatographic conditions and method validation according to legislation. Results of published assays are comparatively presented and criticised.