Determination of nitrofuran metabolites in poultry muscle and eggs by liquid chromatography-tandem mass spectrometry

In-situ growth of MOF-derived Co3S4@MoS2 heterostructured electrocatalyst for the detection of furazolidone

The over-exploitation of antibiotics in food and farming industries ruined the environmental and human health. Consequently, electrochemical sensors offer significant advantages in monitoring these compounds with high accuracy. Herein, MOF-derived hollow Co3S4@MoS2 (CS@MS) heterostructure has been prepared hydrothermally and applied to fabricate an electrochemical sensor to monitor nitrofuran class antibiotic drug. Various spectroscopic methodologies have been employed to elucidate the structural and morphological information. Our prepared electrocatalyst has better electrocatalytic performance than bare and other modified glassy carbon electrodes (GCE). Our CS@MS/GCE sensor exhibited a highly sensitive detection by offering a low limit of detection, good sensitivity, repeatability, reproducibility, and stability results. In addition, our sensor has shown a good selectivity towards the target analyte among other potential interferons. The practical reliability of the sensor was measured by analyzing various real-time environmental and biological samples and obtaining good recovery values. From the results, our fabricated CS@MS could be an active electrocatalyst material for an efficient electrochemical sensing application.

Simultaneous determination of five metabolites of nitrofurans including the metabolite nifursol in shrimp and fish by UPLC- MS/MS: in-house method validation according to commission implementing regulation (EU) 2021/808

For the simultaneous identification and quantification of five nitrofurans metabolites in farmed shrimp and fish, 3-amino-2-oxazolidinone (AOZ), 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ), 1-aminohydantoine (AHD), semicarbazide (SEM), and 3,5-dinitrosalicylic acid hydrazide (DNSH), an accurate, precise, and specific method was developed. The mixture of water and methanol (60/40; v/v) was found to be the final optimised solvent for injection. The analytical run duration was 7 min, and the mobile phase included 2 mM methanol and ammonium formate. The new reference point for action (RPA) of 0.50 µg kg^-1 as per EC/1871/2019 was taken into consideration and evaluated for the performance characteristics as per the CIR (EC)/2021/808 criteria. Specificity, relative retention time (≤0.25%) relative ion ratio (≤40%), linearity (0.25 to 2.0 µg kg^-1), trueness (between 82.8 and 118.1%), repeatability (RSD_r ≤14%), within lab reproducibility (RSD_wr ≤16.9%), CCα (0.32-0.36 μg kg^-1), ruggedness and relative matrix effect (≤14.26%) achieved acceptable values.

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.

UV/solar photo-degradation of furaltadone in homogeneous and heterogeneous phases: Intensification with persulfate

Previous studies on removal of the pharmaceutical drug Furaltadone (FTD) in water have not shown to be totally efficient or are very expensive. In this study, sulfate radicals derived from persulfate anions activated with different irradiation sources (UVA, UVC and solar light) and combined with H₂O₂ and/or TiO₂ have been tested in homogeneous and heterogeneous phases under different operation modes and reaction systems. In homogeneous phase, UV produces a slow mineralization (k = 0.0013 min^-1). The combined processes are faster (k_UV/H2O2 = 0.0185 min^-1, k_UV/PS = 0.0206 min^-1) with the best performance for the UV/PS system yielding nearly 80% of mineralization in half an hour. The overall process (UV/H₂O₂/PS) does not show synergy and mineralization is even slower (k_UV/H2O2/PS = 0.015 min^-1) due to the production of a high amount of radicals favouring unproductive reactions (scavenger effect). A mineralization mechanism is proposed involving formation of 5hydroxymethylene-2(5H)-furanone and NO as the main intermediates. In heterogeneous phase (UVA/TiO₂/PS), the holes play an important role changing the mineralization mechanism. The main intermediates formed were C₁₂H₁₇N₄O₄ and C₁₁H₁₄N₃O₄, which rapidly were degraded to form C₈H₁₅O₃N₃, C₄H₁₀NO and C₅H₁₀NO. An economic study of operation costs has been made for selected processes: UVC/PS, UVA/TiO₂/PS and Solar/TiO₂/PS. The Solar/TiO₂/PS process has the lowest operation costs due to the use of solar energy. However, it would need an additional stage to recover the catalyst. Finally, a loss of 27% in efficiency during mineralization was found after 5 cycles, but the catalyst recovers its initial performance after regeneration at 500 °C.

Electrochemically functionalized graphene for highly sensitive detection of nitrofurazone

The electrochemically functionalized graphene nanosheets (EGS) possesses more oxygen-containing groups and higher defect level, showing superior electrochemical sensing performance.

Development and validation of a rapid LC-MS/MS method for the confirmatory analysis of the bound residues of eight nitrofuran drugs in meat using microwave reaction

A rapid analytical method was developed and validated for the analysis of eight bound nitrofurans in animal tissue, shortening laboratory turnaround times from 4 to 2 days. The majority of methodologies for nitrofuran analysis focus on the detection of only four drugs (nitrofurantoin, furazolidone, furaltadone and nitrofurazone), and is time-consuming given the 16-h overnight derivatisation step and a double liquid–liquid extraction. In this study, the narrow scope of analysis was addressed by including further four important nitrofuran drugs (nifursol, nitrofuroxazide, nifuraldezone and nitrovin). Full chromatographic separation was achieved for the metabolites of all eight nitrofurans, using phenyl-hexyl column chemistry and a rigorous optimisation of the mobile phase additives and gradient profile. The conventional, lengthy sample preparation was substantially shortened by replacing the traditional overnight water bath derivatisation with a rapid 2-h microwave-assisted reaction, followed by a modified-QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) extraction. This confirmatory method was fully validated in accordance with the new 2021/808/EC legislation, and was shown to perform satisfactorily when applied to incurred tissues. The decision limit (CCα) for the eight analytes ranged between 0.013 and 0.200 µg kg⁻¹, showing abundant sensitivity given that the current RPA for nitrofurans is 0.5 µg kg⁻¹. This innovative method can play a major role in the surveillance of the illegal use of nitrofuran drugs.

Presence of nitrofurans and their metabolites in gelatine

Following the detection of semicarbazide (SEM) in gelatine by Italian Authorities, at levels exceeding by three times the reference point for action (RPA) of 1 μg/kg, set out by Commission Regulation (EU) 2019/1871 for nitrofurans and their metabolites, the European Commission mandated EFSA to investigate the available sources of nitrofurans and their metabolites in gelatine. European Commission also asked EFSA to provide approaches that would distinguish SEM occurring due to illegal treatment with nitrofurazone from SEM produced during food processing. The literature indicates that SEM, both free and bound to macromolecules, could occur also in food products such as gelatine, during food processing, arising from the use of disinfecting agents and/or from reactions of various food components and, therefore, SEM cannot be considered as an unequivocal marker of the abuse of nitrofurazone in animal production. It is recommended to investigate in more detail which processing conditions lead to the formation of SEM in gelatine during its production and what levels can be found. One potential approach to distinguishing between SEM from nitrofurazone and SEM from other sources in food products, such as gelatine, might be based on determining the ratio of bound:free SEM in a sample of gelatine. However, whether the ratio of bound:free SEM would unequivocally distinguish between SEM arising from nitrofurazone abuse or from other sources still needs to be demonstrated.

A competitive-type electrochemical immunosensor based on Ce-MOF@Au and MB-Au@Pt core-shell for nitrofuran metabolites residues detection

A novel competitive-type electrochemical immunosensor based on square wave voltammetry (SWV) response was developed for the quantitative detection of 1-Aminohydantoin (AHD). To improve the conductivity of this immunosensor nanocomposites with good electrical conductivity were prepared as a signal amplification platform for the immunosensor by growing Au nanoparticles on the surface of Ce-based metal-organic framework (Ce-MOF). In addition, methylene blue (MB)-loaded Au@Pt and coating antigen (OVA-AHD) connected as a signal label. When the target was introduced, it competed with the coating antigen for the Ab, which led to a reduction in the number of signal probes bound to the Ab. The concentration of AHD can be determined by SWV detection of the MB signal loaded on the signal labels. Under optimal conditions, the wide linear range of 0.001-1000 μg /L and a low detection limit of 1.35 × 10^-7 μg/L were achieved. Ultimately, the developed method displayed excellent specificity in practical applications, providing a promising probability to detect nitrofuran metabolites residues to guarantee food safety.

Determination of semicarbazide residue in human urine samples using liquid chromatography-tandem mass spectrometry

An ultra-performance liquid chromatography coupled with electrospray ionisation tandem mass spectrometry (UPLC-ESI-MS/MS) with pre-column derivatisation was developed and validated for the determination of semicarbazide in human urine. Urine samples were derivatised with 2-nitrobenzaldehyde and subsequently extracted with acetonitrile. Extracts were concentrated and then analysed by UPLC-MS/MS. The time per run was 7 min. Good results were observed for the linearity of matrix-matched calibration curves (R² > 0.99) in the concentration range of 1-100 µg/L. The absolute recovery ranged from 98.7% to 108.6%, with the relative standard deviations (RSDs) of 2.2%-3.6%. The limit of detection and quantification for the semicarbazide was 0.5 µg/L and 1 µg/L, respectively. The method showed good extraction efficiency, high sensitivity, and good reproducibility. It was suitable for the detection of semicarbazide in human urine. Residues of semicarbazide were between 1.0 and 41.5 μg/L in children's 24-h urine. This work is the first report on the quantitative analysis of SEM in 24-h human urine samples.

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.

Confirmation of five nitrofuran metabolites including nifursol metabolite in meat and aquaculture products by liquid chromatography-tandem mass spectrometry: Validation according to European Union Decision 2002/657/EC

LC-MS/MS method for confirmation of nitrofuran metabolites in meat and aquaculture products, including the nifursol metabolite (DNSH), was developed. The nitrofuran metabolites investigated were as follows: 3-amino-2-oxazolidinone (AOZ), 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ), 1-aminohydantoine (AHD), semicarbazide (SEM) and 3,5-dinitrosalicylic acid hydrazide (DNSH). The sample preparation includes a washing step, allowing to analyze only the fraction of protein-bound residues. The final optimized recovery solvent for injection was found to be a mixture of ammonium acetate 2 mM/acetonitrile (60/40 ; v/v). Matrix effects and stability in biological matrix and standard solution for DNSH have been also carried out. Method performances were assessed using criteria of the Decision (EC) No 2002/657 and considering the proposed-for-adoption reference point for action (RPA) of 0.50 µg.kg^-1 under Reg 1871/2019. Trueness ranged 86.5%-103.7% and precision ranged 2.0%-6.5% on intra-laboratory reproducibility conditions. Decision limit (CCα) ranged 0.028-0.182 μg.kg^-1 and capability of detection limit (CCβ) ranged 0.032-0.233 µg.kg^-1.

Determination of four nitrofuran metabolites in gelatin Chinese medicine using dispersive solid phase extraction and pass-through solid phase extraction coupled to ultra high performance liquid chromatography-tandem mass spectrometry

This study established a validated analytical method for the first time on the determination of nitrofuran metabolites, including semicarbazide (SEM), 1-aminohydantoin (AHD), 3-amino-2-oxazolidinone (AOZ) and 3-amino-5-morpholinomethyl-2-oxazolinone (AMOZ) in gelatin Chinese medicine. A C₁₈ column with the mobile phase consisting of acetonitrile and 5 mmol/L ammonium acetate in water was used to separate these nitrofuran metabolites. The limit of detection of SEM, AHD, AOZ and AMOZ were found to be 0.2 µg/kg, 0.3 µg/kg, 0.2 µg/kg and 0.2 µg/kg, whereas their limit of quantification were 0.6 µg/kg, 0.8 µg/kg, 0.6 µg/kg and 0.5 µg/kg. These nitrofuran metabolites exhibited a good linear standard curve (regression coefficients above 0.99) with a concentration range of 2 µg/L to 100 µg/L. Regarding extraction procedure, gelatin Chinese medicine was pre-treated with pepsin and then extracted using 5% formic acid (v/v) in acetonitrile. The resultant extract was purified through dispersive solid phase extraction using 1000 mg anhydrous sodium sulfate, 300 mg octadecyl carbon silica gel sorbent absorbent and 500 mg ethylenediamine-N-propyl carbon silica gel absorbent, and then further purified on Oasis PRiME HLB cartridges. The matrix effect was effectively eliminated after the clean-up procedure as confirmed by comparing the ratio of standard curves prepared by standards dissolved in both matrix solvent and 5 mmol/L ammonium acetate in water: acetonitrile (95:5, v/v). The recoveries of these nitrofuran metabolites under the 1 µg/kg, 2 µg/kg and 10 µg/kg spiking levels were between 77.4% and 95.6%. These metabolites after the extraction were stable at 4 °C for 24 h. The validated method was used to analyze the residue level of these nitrofuran metabolites in 25 gelatin Chinese medicines. Results showed that only one Colla Corii Asini sample contained SEM (2.52 µg/kg) and AOZ (6.27 µg/kg), whereas one Testudinis Carapacis et Plastri sample had SEM (1.27 µg/kg) and AMOZ (9.53 µg/kg).

Determination of 3,5-Dinitrosalicylic Acid Hydrazide in Honey by Solid-Phase Extraction-Ultraperformance Liquid Chromatography-Tandem Mass Spectrometry

ABSTRACT

3,5-Dinitrosalicylic acid hydrazide (DNSAH) is the metabolite of the antibacterial nitrofuran nifursol. A simple and accurate analytical method to determine DNSAH levels in honey by solid-phase extraction-ultraperformance liquid chromatography-tandem mass spectrometry has been established. The honey sample was hydrolyzed under acidic conditions and derivatized with 2-nitrobenzaldehyde in the dark for 16 h, followed by solid-phase extraction and column chromatography. Detection was performed with an electrospray ionization source and multiple reaction monitoring mode and was quantified by the internal standard method. The detection and quantitative limits of DNSAH in honey were 0.1 and 0.3 μg/kg, respectively. Good linear relationships between peak areas and mass concentrations of the analyte were achieved in the range of approximately 0.1 to 200 μg/L, with the correlation coefficient >0.9991. Under the concentration levels of 0.2, 0.5, 1.0, and 2.0 μg/kg, the average recovery rate were between 98.5 and 102.3%, and the relative standard deviations were between 1.1 and 5.4%. The results indicate that the method is simple, rapid, sensitive, and reproducible and can be used to determine DNSAH levels in different types of honey.

HIGHLIGHTS

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.

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.

Microsomal oxidative stress induced by NADPH is inhibited by nitrofurantoin redox biotranformation

Nitrofurantoin is used in the antibacterial therapy of the urinary tract. This therapy is associated with various adverse effects whose mechanisms remain unclear. Diverse studies show that the nitro reductive metabolism of nitrofurantoin leads to ROS generation. This reaction can be catalyzed by several reductases, including the cytochrome P450 (CYP450) reductase. Oxidative stress arising from this nitro reductive metabolism has been proposed as the mechanism underlying the adverse effects associated with nitrofurantoin. There is, however, an apparent paradox between these findings and the ability of nitrofurantoin to inhibit lipid peroxidation provoked by NADPH in rat liver microsomes. This work was aimed to show the potential contribution of different enzymatic systems to the metabolism of this drug in rat liver microsomes. Our results show that microsomal lipid peroxidation promoted by NADPH is inhibited by nitrofurantoin in a concentration-dependent manner. This suggests that the consumption of NADPH in microsomes can be competitively promoted by lipid peroxidation and nitrofurantoin metabolism. The incubation of microsomes with NADPH and nitrofurantoin generated 1-aminohidantoin. In addition, the biotransformation of a classical substrate of CYP450 oxidative system was competitively inhibited by nitrofurantoin. These results suggest that nitrofurantoin is metabolized through CYP450 system. Data are discussed in terms of the in vitro redox metabolism of nitrofurantoin.

Development of an accelerated solvent extraction, ultrasonic derivatisation LC-MS/MS method for the determination of the marker residues of nitrofurans in freshwater fish

A rapid method using accelerated solvent extraction (ASE) and ultrasound enhanced derivatisation has been developed for the quantitative determination of metabolites of nitrofurans, namely 3-amino-2-oxalidinone (AOZ), 5-morpholinomethyl-3-amino-2-oxalidinone (AMOZ), 1-amino-hydantoin (AHD) and semicarbazide (SEM), in muscle and skin of carp and finless eel. The target analytes were extracted using ASE, ultrasonic derivatisation for 1 h and then purified by solid phase extraction. Averaged decision limits (CCα) and detection capability (CCβ) of the method were in the range of 0.07-0.13 and 0.31-0.49 µg kg⁻¹ in carp and finless eel, respectively. The accuracy in terms of recovery was in the range 77.2-97.4%. The simplified and traditional methods were compared with incurred residue samples. The simplified method reduced the derivatisation time and has been applied to the determination of nitrofurans residues in fish.

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.

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.

Potential role of cysteine and methionine in the protection against hormonal imbalance and mutagenicity induced by furazolidone in female rats

The use of nitrofurans as veterinary drugs has been banned in the EU since 1993 due to doubts on the safety of the protein-bound residues of these drugs in edible products. Furazolidone (FUZ) is a nitrofuran drug, which has been used for many years as an antibacterial drug in veterinary practice. The aim of the current study is to investigate the role of L-cysteine and L-methionine in the protection against hormonal imbalance and the genotoxicity induced by FUZ using the micronucleus (MN) assay and random amplified polymorphism DNA (RAPD-PCR) analysis in female rats. Forty female Sprague-Dawley rats were divided into four groups included the untreated control group; a group treated with FUZ (300 mg/kg b.w.); a group treated with a mixture of L-cysteine (300 mg/kg b.w.) and L-methionine (42.8 mg/kg b.w.) and a group treated with FUZ plus the mixture of L-cysteine and L-methionine for 10 days. The results indicated that FUZ induced hormonal disturbances involving thyroid, ovarian and adrenal hormones. Moreover, FUZ increased the micronucleus formation and induced changes in polymorphic band patterns. The combined treatment with FUZ and the mixture of L-cysteine and L-methionine succeeded to prevent or diminish the endocrine disturbance and the clastogenic effects of FUZ. The current study is casting new light on the complex mechanisms underlying the ameliorating action of dietary L-cysteine and L-methionine against FUZ toxicity in experimental animals.

Matrix-comprehensive in-house validation and robustness check of a confirmatory method for the determination of four nitrofuran metabolites in poultry muscle and shrimp by LC–MS/MS

An already well-described method for the determination of nitrofuran metabolites 3-amino-5-methyl-morpholino-2-oxazolidinone (AMOZ), 3-amino-2-oxazolidinone (AOZ), semicarbazide (SEM) and 1-aminohydantoin (AHD) was adapted to the needs of our laboratory and checked for its robustness regarding sample conditions and the processing step. Using the same data, the method was validated and the measurement uncertainty was estimated. All criteria and requirements of Commission Decision 2002/657/EC were fulfilled. The CC(alpha) determined lies between 0.1 and 0.7 microg/kg, the CC(beta) lies between 0.1 and 0.9 microg/kg, the measurement uncertainty was estimated as being between 7 and 17% taking into account matrix, time and sample preparation influences.

Development and validation of an analytical method for the determination of semicarbazide in fresh egg and in egg powder based on the use of liquid chromatography tandem mass spectrometry

In this work the development of a method to determine semicarbazide (SEM) in fresh whole egg and in whole egg and egg white powders as those used in the food industry, by using LC-MS/MS is described. The method is based on a recently validated one for the determination of SEM in baby food. SEM is extracted from egg with 0.2 mol L(-1) hydrochloric acid and derivatised with 2-nitrobenzaldehyde. The extract is neutralised and purified by passing through a solid phase extraction (SPE) cartridge. The 2-nitrobenzaldehyde derivative is eluted with ethyl acetate. The eluate is evaporated to dryness and the residue re-dissolved in methanol:water mobile phase. SEM is determined by reversed-phase LC-MS/MS. The "in-house" validation of this method has been performed taking into account the "Harmonized guidelines for single-laboratory validation of methods of analysis" (IUPAC Technical report) and the Commission Decision (2002/657/EC). The performance characteristics of the method were established by in-house validation procedures employing assays with standard solutions, sample blanks and spiked samples. Linearity, matrix effect, trueness, precision, selectivity, limits of detection and of quantification were determined. The fitness for purpose of this method was assessed based on its performance characteristics. LOD's of 0.15 and 0.4 microg kg(-1) for whole fresh egg and industrial egg powders, respectively, were obtained. The LOQ for fresh whole egg was 0.2 microg kg(-1) and for industrial egg powders 0.8 microg kg(-1). Linear calibration curves were obtained in the ranges 1-100 and 0.8-400 microg kg(-1) for fresh whole egg and the egg powders, respectively.