Marilena E. Dasenaki

Multi-residue determination of seventeen sulfonamides and five tetracyclines in fish tissue using a multi-stage LC-ESI-MS/MS approach based on advanced mass spectrometric techniques.

A strategy was newly developed to rapidly screen seventeen sulfonamides and five tetracyclines in a single run from fish tissues using ultra-high performance liquid chromatography (UHPLC) coupled with comprehensive mass spectrometric approaches, including precursor-ion scan and data dependent scan. The product ions for precursor-ion scanning were selected by studying the MS/MS fragmentation of the analytes. All sulfonamides share the same diagnostic product ion at m/z 156 in positive MS/MS scan, while for tetracycline antibiotics the diagnostic product ion was proved to be at m/z 153.8. Further characterization of each compound was performed using a data dependent scan. Separation was performed on a Zorbax Eclipse Plus C18 column with a gradient elution using acetonitrile - 0.1% formic acid mobile phase at a flow rate of 0.1 mL min(-1). This approach has proven to be a powerful, highly selective, and sensitive tool for rapid screening and detection of non-targeted components in fish tissue and requires a minimum sample preparation such as one generic extraction step with MeOH:ACN 50:50 (v/v) acidified with 0.05% formic acid. The method has also been applied successfully to porcine and poultry meat. The validation of such a screening method was performed for the first time according to Commission Decision 2002/657/EC and satisfactory method performance characteristics were achieved.

Multi-residue determination of 115 veterinary drugs and pharmaceutical residues in milk powder, butter, fish tissue and eggs using liquid chromatography–tandem mass spectrometry

A simple and sensitive multi-residue method for the determination of 115 veterinary drugs and pharmaceuticals, belonging in more than 20 different classes, in butter, milk powder, egg and fish tissue has been developed. The method involves a simple generic solid-liquid extraction step (solvent extraction, SE) with 0.1% formic acid in aqueous solution of EDTA 0.1% (w/v)-acetonitrile (ACN)-methanol (MeOH) (1:1:1, v/v) with additional ultrasonic-assisted extraction. Precipitation of lipids and proteins was promoted by subjecting the extracts at very low temperature (-23°C) for 12h. Further cleanup with hexane ensures fat removal from the matrix. Analysis was performed by liquid chromatography coupled with electrospray ionization and tandem mass spectrometry (LC-ESI-MS/MS). Two separate runs were performed for positive and negative ionization in multiple reaction monitoring mode (MRM). Particular attention was devoted to extraction optimization: different sample-to-extracting volume ratios, different concentrations of formic acid in the extraction solvent and different ultrasonic extraction temperatures were tested in butter, egg and milk powder samples. The method was also applied in fish tissue samples. It was validated, on the basis of international guidelines, for all four matrices. Quantitative analysis was performed by means of standard addition calibration. For over 80% of the analytes, the recoveries were between 50% and 120% in all matrices studied, with RSD values in the range of 1-18%. Limits of detection (LODs) and quantification (LOQs) ranged from 0.008 μg kg(-1) (oxfendazole in butter) to 3.15 μg kg(-1) (hydrochlorthiazide in egg). The evaluated method provides reliable screening, quantification, and identification of 115 veterinary drug and pharmaceutical residues in foods of animal origin and has been successfully applied in real samples.

Qualitative Multiresidue Screening Method for 143 Veterinary Drugs and Pharmaceuticals in Milk and Fish Tissue Using Liquid Chromatography Quadrupole-Time-of-Flight Mass Spectrometry

A wide-scope screening methodology has been developed for the identification of veterinary drugs and pharmaceuticals in fish tissue and milk using ultrahigh-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS). The method was validated using a qualitative approach at two concentration levels. The detection of the residues was accomplished by retention time, accurate mass, and the isotopic fit using an in-house database. Product-ion spectra were used for unequivocal identification of the compounds. Generic sample treatment was applied. The majority of the compounds were successfully detected and identified at concentration levels of 150 ng mL(-1) in milk and 200 μg kg(-1) in fish (>80% of the compounds in both matrices), whereas satisfactory results were also obtained at concentration levels of 15 ng mL(-1) in milk and 20 μg kg(-1) in fish (>60% of the compounds detected and identified).

Analysis of 76 veterinary pharmaceuticals from 13 classes including aminoglycosides in bovine muscle by hydrophilic interaction liquid chromatography-tandem mass spectrometry.

A multiresidue/multiclass method for the simultaneous determination of 76 veterinary drugs and pharmaceuticals in bovine muscle tissue has been developed and validated according to the requirements of European Commission Decision 2002/657/EC. The analytes belong in 13 different classes, including aminoglycoside antibiotics, whose different physicochemical properties (extremely polar character) render their simultaneous determination with other veterinary drugs quite problematic. The method combines a two-step extraction procedure (extraction with acetonitrile followed by an acidic aqueous buffer extraction) with hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) determination, allowing confirmation and quantification in a single chromatographic run. Further cleanup with solid phase extraction was performed using polymeric SPE cartridges. A thorough ionization study of aminoglycosides was performed in order to increase their sensitivity and significant differences in the abundance of the precursor ions of the analytes were revealed, depending on the composition of the mobile phase tested. Further gradient elution optimization and injection solvent optimization were performed for all target analytes.The method was validated according to the European Commission Decision 2002/657. Quantitative analysis was performed by means of standard addition calibration. Recoveries varied from 37.4% (bromhexine) to 106% (kanamycin) in the lowest validation level and 82% of the compounds showed recovery >70%. Detection capability (CCβ) varied from 2.4 (salinomycin) to 1302 (apramycin) μgkg(-1).

Simultaneous determination of eighteen perfluorinated compounds in dissolved and particulate phases of wastewater, and in sewage sludge by liquid chromatography-tandem mass spectrometry

Perfluorinated compounds (PFCs) are known chemicals that are used in a wide variety of industrial and consumer products, and have been reported to exist in the environment as contaminants. In this study, a liquid chromatography-electrospray-tandem mass spectrometry (LC-ESI-MS/MS) method was developed for simultaneous determination of 10 perfluoroalkyl carboxylate acids (PFCAs), 5 perfluoroalkyl sulfonates (PFASs), and 3 perfluoroalkyl sulfonamides (PFSAs) (18 PFCs in total), in dissolved and particulate phases of wastewater (raw and treated), and in dewatered sewage sludge. The target PFCAs were perfluoropentanoic acid (PFPeA; C5), perfluorohexanoic acid (PFHxA; C6), perfluoroheptanoic acid (PFHpA; C7), perfluorooctanoic acid (PFOA; C8), perfluorononanoic acid (PFNA; C9), perfluorodecanoic acid (PFDA; C10), perfluoroundecanoic acid (PFUdA; C11), perfluorododecanoic acid (PFDoA; C12), perfluorotridecanoic acid (PFTrDA; C13), and perfluorotetradecanoic acid (PFTeDA; C14). The target PFASs were potassium perfluorobutanesulfonate (PFBS; C4), sodium perfluorohexanesulfonate (PFHxS; C6), sodium perfluoroheptanesulfonate (PFHpS; C7), sodium perfluorooctanesulfonate (PFOS; C8), and sodium perfluorodecanesulfonate (PFDS; C10), and the target PFSAs were perfluorooctane sulfonamide (PFOSA), N-methylperfluorooctane sulfonamide (N-MeFOSA), and N-ethylperfluorooctane sulfonamide (N-EtFOSA). Wastewater samples were filtered after collection and extracted/purified/pre-concentrated by a solid-phase extraction (SPE) procedure. Particulate matter and sludge samples were extracted by a liquid–solid extraction (LSE) and ultra-sonication procedure, and thereafter purified/preconcentrated by the same SPE procedure that was followed for the dissolved phase of wastewater. The internal standards, perfluoro-n-[1,2,3,4-13C4]octanoic acid (13C4-PFOA), sodium perfluoro-1-[1,2,3,4-13C4]octanesulfonate (13C4-PFOS), and N-methyl-d3-perfluoro-1-octanesulfonamide (2D3-N-MeFOSA) provided adequate compensation for variations in the extraction percentages and instrumental response. The limits of quantification (LOQs) ranged from 0.29 (PFHpS) to 3.0 ng L−1 (PFDoA) for dissolved phase samples, and from 0.15 (PFHpS) to 1.5 ng g−1 dry weight (dw) (PFDoA) for particulate matter and sludge samples. The developed methods were applied successfully to wastewater and sludge samples originated from Athens WWTP. PFC concentrations up to 113 ng L−1 (PFUdA), 33 ng L−1 (PFOA) and 1042 ng g−1 (PFUdA) were determined in influent wastewater, treated wastewater and dewatered sludge, respectively. Analysis of PFCs in the particulate matter of wastewater is needed to avoid underestimation of their concentrations.

Liquid chromatography-tandem mass spectrometric methods for the determination of spinosad, thiacloprid and pyridalyl in spring onions and estimation of their pre-harvest interval values.

Two liquid chromatography-tandem mass spectrometric methods were developed and validated to determine spinosyn A and D, thiacloprid and pyridalyl in spring onions cultivated under Egyptian field conditions. The degradation rates, the pre-harvest interval (PHI) values and the half-life values of the three pesticides were estimated. QuEChERS was used for sample preparation and the separation was performed on an X-Bridge C18 column with ACN-formic acid 0.1% as the mobile phase. Linear range, method detection limits (MDLs), precision, recovery and matrix effects were estimated. The multi-residue MDLs ranged from 0.02μg/kg (spinosyn A & D) to 0.05μg/kg for pyridalyl. All the investigated pesticides showed high degradation rates. For spinosad the half-life value was 1.2days, for thiacloprid it reached 2.2days and for pyridalyl 4.4days. Furthermore, the calculated PHI values, according to the maximum residue levels set by the EU, were 0days for spinosad, 9.8days for thiacloprid and 39.4days for pyridalyl.

Benzosulfonamides in wastewater: Method development, occurrence and removal efficiencies

Benzosulfonamides (BeSAs) are a family of compounds with a broad application as industrial chemicals: plasticizers, intermediates for pesticides and drugs or used in the production of artificial sweeteners, among others. BeSAs constitute a class of organic compounds of emerging environmental concern. However, analytical methodologies for their determination in the environment are scarce as well as there is a lack of environmental occurrence data for these substances. An analytical methodology based on pseudo-SRM liquid chromatography-tandem mass spectrometry (LC-(ESI-)MS/MS) was developed and optimized for the determination of three BeSAs (benzenesulfonamide (BSA), o-toluenesulfonamide (o-TSA) and p-toluenesulfonamide (p-TSA)) in wastewater. The solid phase extraction protocol was also carefully optimized. The method provided recoveries in the range 83-118% (three different fortification levels). Good precision (<10.2% (intra-day) and <13.6% (inter-day)) and limits of detection achieved (11-89 ng L(-1)) allow a reliable quantification of these compounds in both effluent and influent wastewaters. The presence of BeSAs has been evaluated during seven consecutive days in influent and effluent samples from the wastewater treatment plant of Athens, Greece. o-TSA and p-TSA were detected in 100% of the samples, while BSA was detected in all the influents and in 43% of the effluents. All three compounds were determined in relevant concentrations (up to 1.4 μg L(-1) in the case of p-TSA), constituting the first evidence of the presence of these compounds in Greece, and contributing to the scarce occurrence data. Removal efficiencies of BeSAs during wastewater treatment was also assessed and discussed. In this regard, different behaviors were observed: while BSA and p-TSA were removed in different rates, o-TSA was formed during wastewater treatment. A daily load of 0.48 kg of o-TSA and 0.47 kg of p-TSA was discarded in the receiving Saronikos Gulf.

Meat Safety: II Residues and Contaminants

This chapter reviews the various aspects of chemical contamination of meat and meat products covering the major groups of residues and contaminants, such as veterinary drugs, pesticides, mycotoxins, dioxins, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, heavy metals, etc. The properties, occurrence, sources, and legal framework of each group of contaminants are described. Special attention was paid to the issue of pesticide and veterinary drug residues in meat, which is tightly linked to the intensive agricultural and livestock breeding practices, as well as to the presence of emerging contaminants in meat and meat products due to environmental contamination, cultivation practices, or production processes. When present above certain levels, these substances could pose a severe threat to human health. Current and future analytical strategies are also summarized and recent developments in sample preparation and principles, applications, and future perspectives of chromatographic–mass spectrometric techniques are highlighted. Finally, a comprehensive overview of published applications of multiresidue analysis in meat and meat products combining gas chromatography–mass spectrometry, liquid chromatography–mass spectrometry, high resolution mass analyzers, and tandem mass spectrometry methods with generic sample preparation methodologies is presented.

Multi-residue methodology for the determination of 16 coccidiostats in animal tissues and eggs by hydrophilic interaction liquid chromatography – Tandem mass spectrometry

A simple, sensitive and efficient confirmatory method was developed and validated for the determination of 16 coccidiostats in animal tissues and eggs using hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS). The sample preparation consisted of a solid-liquid extraction with ACN and dispersive SPE cleanup with MgSO4 and C18. Analysis was realized in an Acquity BEH HILIC silica column, in SRM mode. Both positive and negative ionization was performed, using polarity switching. Isocratic elution was used with a mobile phase of ACN: aqueous ammonium formate 1 mM with 0.1% formic acid (80:20, v/v). Method validation was performed in eggs, poultry, bovine, ovine, porcine and rabbit tissue and exceptionally low LODs were achieved, varying from 0.004 μg kg-1 (decoquinate in porcine tissue) to 0.560 μg kg-1 (halofuginone in eggs). The developed methodology was applied in 82 muscle and egg samples through the Greek National Residue Control Plan for coccidiostats.