Residue analyses and exposure assessment of the Irish population to nitrofuran metabolites from different food commodities in 2009–2010

An exposure assessment to nitrofuran residues was performed for three human populations (adults, teenagers and children), based on residue analyses of foods of animal origin (liver, honey, eggs and aquaculture) covering the 2-year period 2009–2010. The occurrence of nitrofuran metabolites in food on the Irish market was determined for the selected period using the data from Ireland’s National Food Residue Database (NFRD) and from results obtained from the analysis of retail samples (aquaculture and honey). Laboratory analyses of residues were performed by methods validated in accordance with Commission Decision 2002/657/EC regarding performance of the analytical method and interpretation of results. Semicarbazide (SEM) was the contaminant most frequently identified and its content ranged from 0.09 to 1.27 μg kg^?1. SEM is currently used as a marker of nitrofuran abuse, but it may also occur from other sources. The presence of nitrofuran metabolite 3-amino-2-oxazolidinone (AOZ) was detected in two aquaculture samples (prawns) at 1.63 and 1.14 μg kg^?1, but such a low number of positive cases did not present sufficient data for a full AOZ exposure assessment. Therefore, the evaluation of exposure was focused on SEM-containing food groups only. Exposure assessments were completed using a probabilistic approach that generated 10 iterations. The results of both the upper- and lower-bound exposure assessments demonstrate that SEM exposure for Irish adults, teenagers and children from selected food commodities are well below EFSA-estimated safe levels.     

Occurrence and levels of nitrofuran metabolites in sea cucumber from Dalian,China

The occurrence and levels of nitrofuran metabolites (NFMs) in sea cucumber (SC) from Dalian, China, are reported. Four metabolites including 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ), 3-amino-2-oxazolidinone (AOZ), semicarbazide (SEM) and 1-aminohydantoin (AHD) in different SC products (fresh, instant and dry salted SCs) were measured. The frequency of occurrence for NFMs in all SC samples was 42.7%. The total NFM concentrations ranged from non-detectable to 64.6 ng g^–1, with a mean of 3.59 ng g^–1. AOZ and SEM were the dominant congeners, accounting for 40.1% and 59.1% of the total NFMs, respectively. The concentrations and patterns varied among different regions. Higher levels of NFMs were found in the fresh SC products, and the order for the average concentration of ∑₄NFM was fresh > dry salted > instant.     

Application of LC with Evaporative Light Scattering Detector for Biogenic Amines Determination in Fair Trade Cocoa-Based Products

In this study, the separation of eight biogenic amines (cadaverine, serotonin, histamine, spermidine, spermine, tyramine, putrescine and β-phenylethylamine) by a liquid chromatography (LC) method with evaporative light scattering detection (ELSD) was performed. The LC–ELSD method was validated by comparison of the results with those obtained through LC–ultraviolet (UV) determination, based on a pre-column dansyl chloride derivatisation step, and the recorded data showed as both analytical methods can be interchangeably used for biogenic amines determination. LC–ELSD methodology showed good precision and permitted to achieve, for standard solutions, limits of detection (LOD) ranging from 0.01 to 0.02 μg ml^?1 and limits of quantitation (LOQ) ranging from 0.03 to 0.05 μg ml^?1. The whole methodology, comprehensive of the homogenization–extraction process and LC–ELSD analysis, has been applied in the analysis of several samples of fair trade cocoa derivatives. The most abundant amine found was histamine for a total amount of biogenic amines in the range 5.81–38.82 μg g^?1. The highest amounts of biogenic amines (BAs) were found in the most processed products but never representing a possible risk for consumer health, according to the toxicity levels reported in literature and regarded as acceptable.     

Simultaneous and Fast Determination of Malachite Green, Leucomalachite Green, Crystal Violet, and Brilliant Green in Seafood by Ultrahigh Performance Liquid Chromatography–Tandem Mass Spectrometry

A new procedure has been developed for the simultaneous analysis of malachite green (MG), leucomalachite green (LMG), crystal violet (CV), and brilliant green (BG) in seafood using a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure and subsequent determination by ultrahigh performance liquid chromatography coupled to tandem mass spectrometry in <5.5 min. The developed method was validated at 2, 10, 25, and 100 μg kg^?1, obtaining recoveries in the range of 48–112 %, with repeatability and interday precision values (expressed as relative standard deviation) ≤17 and ≤24 %, respectively. Matrix effect was evaluated for different types of seafood (shrimp, salmon, and trout), indicating that shrimp can be chosen as representative matrix for the determination of the selected dyes, except for LMG. Limits of quantification (LOQs) were <0.5 μg kg^?1, which were always below the minimum required performance limits established by the European Union. The decision limit (CC_α) and detection capability (CC_β) values were also estimated in the three matrices evaluated, and CC_β ranged from 0.46 to 1.22 μg kg^?1. Finally, several types of seafood were analyzed, and some dye residues (MG, CV and BG) were detected in a salmon sample.     

Migration of Ti from nano-TiO2-polyethylene composite packaging into food simulants

An analytical method based on ICP-MS was developed for the determination of Ti in food simulants (3% (w/v) aqueous acetic acid and 50% (v/v) aqueous ethanol). The method was used to determine the migration of Ti from nano-TiO₂-PE films used for food packaging into food simulants under different temperature and migration time conditions. The maximum migration amounts into 3% (w/v) aqueous acetic acid were 1.4 ± 0.02, 6.3 ± 0.5 and 12.1 ± 0.2 μg kg^?1 at 25, 70 and 100°C, respectively, while into 50% (v/v) aqueous ethanol, the maximum migration amounts were 0.5 ± 0.1, 0.6 ± 0.03 and 2.1 ± 0.1 μg kg^?1 at 25, 70 and 100°C, respectively. Increasing the additive content in the film promoted migration of nanoparticles. The results indicated that the migration of nanoparticles might occur via dissolution from the surface and cut edges of the solid phase (film) into the liquid phase (food simulant).     

Determination of Hormones Residues in Milk by Gas Chromatography-Mass Spectrometry

The article presents the use of gas chromatography-mass spectrometry (GC-MS) technique in a method for the determination of 18 anabolic hormones from synthetic stilbenes, steroids and resorcylic acid lactones (RALs) groups in raw milk and milk powder. Sample preparation consisted of liquid-liquid extraction with diethyl ether and purification by solid phase extraction (SPE). Prior to instrumental analysis, the reaction of derivatisation with the heptafluorobutyric anhydride or N-methyl-N-trimethylsilyltrifluoroacetamide was performed. Method validation was carried out according to the required performance criteria of the Commission Decision 2002/657/EC. The apparent recovery of all analytes at 1 μg L^?1 (kg^?1) level was ranged between 70.4 and 119.4 % with the coefficients of variation values less than 30 %. The decision limits (CCα) and the detection capabilities (CCβ) were in the range of from 0.11 to 0.44 μg L^?1 (kg^?1) and from 0.19 to 0.75 μg L^?1 (kg^?1), respectively. The procedure has been accredited and successfully applied as a screening method for the presence of hormone residues in the study of commercial samples of milk.     

Simultaneous Determination of Cyclamate,Acesulfame, and Aspartame in Beverages by Titania-Based RP-HPLC

This paper aims at establishing a rapid method for simultaneous separation and determination of the sweeteners including cyclamate, acesulfame, and aspartame in beverages by titania-based reversed-phase high-performance liquid chromatography. The chromatographic conditions were as follows: a titania Sachtopore-RP C18 column (250?×?4.6 mm; 5 μm) as a separation column, a mixture of water and methanol at a volume ratio of 95:5 containing 1.0 % phosphate acid used as mobile phase, flow rate of 1.0 mL min^?1, and the detection wavelength was 205 nm. The linear ranges of cyclamate and aspartame were 0.02–8.0 mg mL^?1 with limits of detection (LODs) of 16.35 and 19.56 μg mL^?1, respectively, and their limits of quantitation (LOQs) were 55.50 and 68.50 μg mL^?1, respectively. The recoveries of cyclamate were between 93.52 and 103.54 %. The recoveries of aspartame were between 93.31 and 102.63 %. The linear range of acesulfame was 0.125–50 μg mL^?1 with LOD of 0.08 μg mL^?1 and LOQ of 0.25 μg mL^?1. The recoveries of acesulfame were between 94.34 and 103.21 %. Relative standard deviation (n?=?8) for all determinations was less than 0.72 %.     

Determinative and confirmatory method for residues of tetracyclines in honey by LC-MS/MS

A limited number of substances are authorised for the treatment of bees. Maximum residue limits (MRLs) are set for tetracyclines in several matrices, but not for honey. Nevertheless, tetracycline antibiotics may be used in order to prevent bacterial diseases and the loss of honey bee populations. In this study, a sensitive multi-residue LC-MS/MS method was developed and optimised for the quantitative and qualitative determination of tetracycline residues in honey. Homogenisation of samples under acidic conditions was performed and solid-phase extraction was carried out. The eluate was evaporated under nitrogen and dissolved in an aqueous methanol solution prior to filtration. A mobile phase composed of acetic acid–water and acetic acid–acetonitrile was used. Separation of tetracycline, oxytetracycline, chlortetracycline and doxytetracycline was achieved by using gradient elution on a C18 chromatography column. The analytical method was validated according to Commission Decision 2002/657/EC by the analysis of spiked samples around the recommended concentration of 20 μg kg^?1 by EURL Guidance Paper, December 2007. A matrix effect was observed, so quantification was based on an external matrix calibration curve. Calculated decision limits (CCα) were lower than 10 μg kg^–1 for all tetracyclines. Good linearity, repeatability and within-laboratory reproducibility were achieved.     

Determination of synthetic phenolic antioxidants in soft drinks by stir-bar sorptive extraction coupled to gas chromatography-mass spectrometry

The synthetic phenolic antioxidants butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butyl hydroquinone (TBHQ) were pre-concentrated by stir-bar sorptive extraction and thermally desorbed (SBSE-TD) before analysis by GC-MS. Several parameters affecting the derivatisation step and both SBSE extraction and thermal desorption were carefully optimised. When the analyses of BHA and TBHQ in their acetylated, silylated and underivatised forms were compared, the best results were obtained when the in-situ derivatisation procedure with acetic anhydride was employed. Quantification was carried out using carvacrol as the internal standard, providing quantification limits of between 0.11 and 0.15 ng ml^?1, depending on the compound. Recovery assays for samples spiked at two concentration levels, 1 and 5 ng ml^?1, provided recoveries in the 81–117% range. The proposed method was applied in the analysis canned soft drinks and the analytes were found in five of the 10 samples analysed.     

High-performance liquid chromatography with fluorescence detection for the determination of nitrofuran metabolites in pork muscle

A simple and sensitive HPLC method with fluorescence detection (HPLC-FLD) is reported for the simultaneous determination of metabolites of four nitrofuran drugs (furazolidone, furaltadone, nitrofurantoin and nitrofurazone) in pork muscle. The method involves acid hydrolysis of the protein-bound drug metabolites and the conjugation of the released side-chains with a novel fluorescence agent 2-hydroxy-1-naphthaldehyde. After liquid–liquid extraction and effective separation of the derivatives on a YMC-Pack Polymer C18 column at 40°C under alkaline conditions, the high fluorescence intensity of these derivatives at emission wavelength λ_em = 463 nm enables their simultaneous determination in pork muscle at concentrations as low as 1 µg kg^?1. The method was validated using blank pork muscle fortified with all four metabolites at 0.5, 1.0 and 2.0 µg kg^?1. Recoveries were > 92.3% with RSDs < 8.5% for all four metabolites. The results obtained with HPLC-FLD and LC-MS/MS methods showed very good agreement for pork muscle samples.     

A New and Fast HPLC Method for Determination of Rutin, Troxerutin, Diosmin and Hesperidin in Food Supplements Using Fused-Core Column Technology

A new and fast high-performance liquid chromatography (HPLC) method using fused-core column for separation of rutin, troxerutin, diosmin, and hesperidin has been developed and used for determination of these flavonoids in food supplements. Efficient separation of flavonoids and internal standard methylparaben was achieved on the fused-core column Ascentis Express RP-Amide (100?×?3.0 mm), particle size 2.7 μm, with mobile phase acetonitrile/water solution of acetic acid pH?3 (30:70, v/v) at a flow rate of 1.0 mL?min^?1 and at temperature 50 °C. The detection wavelengths were set at 283 nm for hesperidin and at 255 nm for rutin, troxerutin, diosmin, and internal standard methylparaben. Under the optimal chromatographic conditions, good linearity with correlation coefficients in the range (r?=?0.9991–0.9998; n?=?7) for all flavonoids was achieved. Commercial samples of food supplements were extracted with 100 % dimethyl sulfoxide using ultrasound bath for 10 min and then diluted to methanol. A 5-μL sample volume of the filtered solution was directly injected into the HPLC system. Accuracy of the method defined as a mean recovery of flavonoids from food supplement matrix was in the range 96.2–104.4 % for all flavonoids. The intraday method precision was satisfactory, and relative standard deviations of sample analysis including preparation and determination of different food supplements were in the range 0.5–3.5 % for all flavonoids. The developed method has shown high sample throughput during sample preparation process, modern separation approach, and short time (5 min) of analysis.     

Development of a Headspace-Solid Phase Microextraction-Gas Chromatography/Mass Spectrometry (HS-SPME-GC/MS) Method for the Determination of Benzene in Soft Drinks

A method based on headspace-solid phase microextraction and gas chromatography with mass spectrometry has been developed and validated for the determination of benzene in soft drinks. The extraction step was optimized using a rotatable central composite design including the following experimental variables: extraction temperature, extraction time, sample weight, and salt concentration. The optimized procedure, which was carried out at 30 °C during 30 min by using a 75 μm carboxen-polydimethylsiloxane fiber, showed good linearity within the concentration range 0–25 μg?kg^?1 (r ² ?>?0.999), mean recoveries from 97.5 to 103.1 %, and coefficients of variation from 1.5 to 13.4 % for repeatability and from 1.5 to 15.7 % for within-laboratory reproducibility. Limits of detection and quantification were calculated at 0.02 and 0.08 μg?kg^?1, respectively. The method was applied to determine the concentrations of benzene in 77 samples of beverages from the Brazilian market. Levels from <0.08 to 10.84 μg?kg^?1 were obtained, which are comparable to those verified in other countries. Most of the samples (72.2 %) contained benzene up to 1 μg?kg^?1.     

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.     

Evaluation of a Selective Approach for the Determination of 5-Nitroimidazoles in Aquaculture Products by Capillary Liquid Chromatography Using Molecularly Imprinted Solid-Phase Extraction

Capillary liquid chromatography with UV detection is proposed for the determination of 5-nitroimidazole residues in aquaculture products. The separation was carried out in a C18 column at 20 °C, using a mobile phase consisting of water and acetonitrile, at 7 μL/min and 320 nm as detection wavelength. Furthermore, full loop injection mode (8 μL) was selected and water was considered as injection solvent. The optimized method was applied to the monitoring of nine 5-nitroimidazoles, including three metabolites, in crab, salmon, prawn, and velvet swimming crab. Molecularly imprinted solid-phase extraction has been evaluated for sample cleanup. The method was characterized in all the matrices in terms of linearity (R ² ≥ 0.9964), precision (repeatability, RSD ≤ 7.9%, and reproducibility, RSD ≤ 11.1%) and trueness (recoveries between 80.4 and 108.7%). Decision limits, CCα, ranging from 0.2 to 1.5 μg/kg and detection capabilities, CCβ, from 0.2 to 1.8 μg/kg, were obtained.     

Comparison of HPLC Separation of Phenylalanine Enantiomers on Different Types of Chiral Stationary Phases

HPLC separation of phenylalanine by using chiral stationary phases (CSPs) with chiral selectors β-cyclodextrin, isopropylcarbamate cyclofructan 6, teicoplanin, and ristocetin were studied. The effects of mobile phase composition and column temperature from 0 to 30 °C on the retention and resolution of enantiomers were investigated. β-cyclodextrin and isopropylcarbamate cyclofructan 6 CSPs showed chiral recognition in normal phase separation mode. The sufficient enantioseparations (resolution values 1.59 and 2.75) were reached using teicoplanin and ristocetin-based stationary phases at 23 °C in reversed-phase mode with mobile phases consist of acetonitrile and water at ratios 75/25 and 60/40 (v/v), respectively. Chiral HPLC system coupled with circular dichroism and polarimetry detector could be used to determine enantiomeric elution order. The optimized and validated HPLC-UV method with teicoplanin-based chiral stationary phase was applied for determination of phenylalanine in real samples. Both of the enantiomeric forms were detected in samples of dietary supplements and L-phenylalanine in samples of energy drinks. Obtained recoveries were higher than 82% with an RSD less than 10%. The HPLC method showed good linearity (correlation coefficients >?0.998) in concentration range 0.1–500 μg mL^?1. The limit of detection was 0.1 μg mL^?1 for both enantiomers.     

Speciation Determination of Selenium in Seafood by High-Performance Ion-Exchange Chromatography-Hydride Generation-Atomic Fluorescence Spectrometry

A high-performance ion-exchange chromatography coupled with hydride generation-atomic fluorescence spectrometry (HPIEC-HG-AFS) method was developed for simultaneous speciation of selenium in seafood. Three selenium species including of selenocystine (Se-Cys), selenome-thionine (Se-Met), and selenite Se(IV) were separated on an anion-exchange column (PRP-X100) with eluent of 30 mM NH₄H₂PO₄ and methanol (39:1, v/v) in 10 min at the flow rate of 1.0 mL min^?1. Variables affecting the HG-AFS detection of selenium species were optimized. The optimum conditions found were the following: reducing agent, 2.0 % of KBH₄, and 5.0 % of HCl; lamp current, 90 mA; photomultiplier tube voltage, 280 V; flow rate of carrier gas, 300 mL min^?1; and shielding gas, 800 mL min^?1. Under the optimized conditions, the good linearity of calibration curves (R ²?>?0.999) between signal of fluorescence and concentration of selenium species was obtained in the range of detection limits (DLs), 80 μg L^?1, and the DLs of Se-Cys, Se-Met, Se(IV) were 1.66, 0.990, 1.10 μg L^?1, respectively. The repeatability of the method, expressed as relative standard deviation, was less than 5.0 % (n?=?10), and the average recoveries for spiked test were from 87.3 to 103 % for three analytes in real seafood samples. The developed HPIEC-HG-AFS method was successfully applied for the speciation of selenium in seafood samples.     

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.     

Determination of Benzalkonium Homologues and Didecyldimethylammonium in Powdered and Liquid Milk for Infants by Hydrophilic Interaction Liquid Chromatography–Mass Spectrometry

In this study, a hydrophilic interaction liquid chromatography–mass spectrometry (HILIC-MS/MS) method for the determination of benzalkonium (BAC) homologues and didecyldimethylammonium (DDAC) was developed. A satisfactory chromatographic separation of BAC homologues and DDAC was achieved using, as mobile phase, acetonitrile–aqueous 50 mM ammonium formate (pH 3.2) (93?+?7 v/v) at 0.3 mL min^?1. The elution order of BAC homologues was from benzyldimethylhexadecylammonium chloride (C₁₆-BAC) to benzyldimethyldecylammonium chloride (C₁₀-BAC), the exact opposite with respect to separation using reversed liquid chromatography. The instrumental method was successfully applied to powdered and liquid milk for infants (about 50 samples). From powdered milk samples, BAC and DDAC were extracted using 5 % formic acid in methanol for 60 min at 60 °C in an ultrasonic bath; after dilution with water and 5 % NH₄OH solution, a purification step using a weak cationic exchange column was performed. Satisfactory limit of detections (LODs) were achieved, below 1.0 μg kg^?1 and 0.05 μg L^?1 for powdered and liquid milk for infants, respectively. No sample was free of BAC homologues and DDAC, and in one powdered milk sample, the contamination level exceeded 500 μg kg^?1, the maximum level recommended by the Standing Committee on the Food Chain and Animal Health for food and feed.     

Biogenic amines in commercially produced Yulu,a Chinese fermented fish sauce

Seven biogenic amines were determined in 35 commercially produced Yulu samples from three provinces of China by pre-column derivatisation with dansyl chloride (Dns-Cl) and high-performance liquid chromatography with fluorescence detection (HPLC-FLD). Putrescine, cadaverine, histamine and tyramine were the major biogenic amines (more than 100 mg kg^?1), while tryptamine, spermidine and spermine were regarded as minor biogenic amines (less than 25 mg kg^?1). Twenty samples contained more than 50 mg kg^?1 histamine (the limit for histamine in seafood products as suggested by the Food and Drug Administration). Twenty-one samples contained more than 100 mg kg^?1 tyramine and 10 contained more than 1000 mg kg^?1 total biogenic amines. This study provided data on biogenic amine levels in Chinese fermented fish sauce. The results suggested that biogenic amine content should be monitored in commercially produced Yulu.     

Occurrence of glyphosate and AMPA residues in soy-based infant formula sold in Brazil

Glyphosate is an herbicide widely used in the world, being applied in several crops, among them soybeans. Recently, glyphosate and its metabolite aminomethylphosphonic acid (AMPA) have been identified as possible contributors to the emergence of various diseases such as autism, Parkinson’s and Alzheimer’s diseases, as well as cancer. The child population-consuming cereal-based foods is the most exposed to the effects of pesticides because of their developmental phase and they have a higher food intake per kilogram of body weight than adults. The presence of glyphosate and AMPA residues in soy-based infant formulas was evaluated during the years 2012–2017, totalising 105 analyses carried out on 10 commercial brands from different batches. Glyphosate and AMPA were determined by liquid chromatography with fluorescence detection after derivatisation reaction. The method was validated and showed accuracy and precision with a limit of quantification (LOQ) of 0.02 mg kg^?1. Among those samples that contained levels above the LOQ, the variation of glyphosate residues was from 0.03 mg kg^?1 to 1.08 mg kg^?1 and for AMPA residues was from 0.02 mg kg^?1 to 0.17 mg kg^?1. This is the first scientific communication about glyphosate and AMPA contamination in soy-based infant formula in Brazil, The study was conducted under good laboratory practice (GLP) and supported by good scientific practice.