Suchergebnisse

The use of the novel atmospheric pressure chemical ionization (APCI) source for gas chromatography (GC) coupled to triple quadrupole using tandem mass spectrometry (MS/MS) and its potential for the simultaneous determination of the 12 dioxin-like polychlorobiphenyls (DL-PCBs) in complex food and feed matrices has been evaluated. In first place, ionization and fragmentation behavior of DL-PCBs on the APCI source under charge transfer conditions has been studied followed by their fragmentation in the collision cell. Linearity, repeatability and sensitivity have been studied obtaining instrumental limits of detection and quantification of 0.0025 and 0.005 pg µL-1 (2.5 and 5 fg on column) respectively for every DL-PCB. Finally, application to real samples has been carried out and DL-PCB congeners (PCB 77, 81, 105, 114, 118, 123, 126, 156, 157, 167, 169, 189) have been detected in the different samples in the range of 0.40 to 10000 pg g-1. GC-(APCI)MS/MS has been proved as a suitable alternative to the traditionally accepted confirmation method based on the use of high resolution mass spectrometry and other triple quadrupole tandem mass spectrometry techniques operating with electron ionization. The development of MS/MS methodologies for the analysis of dioxins and DL-PCBs is nowadays particularly important, since this technique was included as a confirmatory method in the present European Union regulations that establish the requirements for the determination of these compounds in food and feed matrices. ; The authors acknowledge the financial support of Generalitat Valenciana, (research group of excellence PROMETEO/2009/054 and PROMETEO II 2014/023 and Collaborative Research on Environment and Food-Safety (ISIC/2012/016))

The presence of a wide variety of organic pollutants with different physico-chemical characteristics has been investigated in wastewater samples from a municipal solid waste treatment plant placed at Castellón, Spain. An advanced analytical strategy has been applied, consisting on the combined used of two powerful and complementary techniques, GC and LC, both hyphenated with tandem mass spectrometry with triple quadrupole analyzers. The GC-MS/MS method was based on sample extraction using C18 SPE cartridges and allowed the determination of around 60 compounds from different chemical families, such as PAHs, octyl/nonyl phenols, PCBs, organochlorine compounds, insecticides, herbicides and PBDEs. Most of compounds selected are included as priority contaminants in the European Union (EU) Water Directive. The UHPLC-MS/MS method, which provided high chromatographic resolution and sensitivity and short analysis time, used a sample extraction with OASIS HLB SPE cartridges and allowed the determination of 37 (more polar) pesticides. The methodology developed has been applied to the analysis of 41 water samples (20 non-treated, raw leachates, and 21 treated) collected between March 2007 and February 2009. Treated (reverse osmosis) water samples analyzed rarely exceeded 0.5 μg/L for the contaminants investigated. As expected, in non-treated leachates the number of detections and the concentration levels found were notably higher than in treated waters. The most commonly detected pollutants were herbicides (simazine, terbuthylazine, terbutryn, terbumeton, terbacil and diuron), together with fungicides (thiabendazole and carbendazim) and 4-t-octylphenol. In the light of data obtained, it has been proven that reverse osmosis process used for water treatment was efficient and notably reduced the levels of organic contaminants found in raw leachate samples. 2 In order to investigate the presence of other non-target contaminants, water samples were also analyzed by using GC-TOF MS and LC-QTOF MS. Several organic pollutants that ...

With the increase of the demand of low flavouring smoked seafood products, there is a need of methodologies able to distinguish between different seafood treatments, as not all of them are allowed in all markers. Following this objective, in the present work an untargeted volatolomics approach was applied to identify volatile markers that demonstrate that Cold smoked products can be distinguished from Tasteless smoke neither Carbon monoxide treated seafood, which are prohibited in the European Union. The use of dynamic headspace for the volatile extraction followed by thermal desorption in combination with Gas Chromatography (GC) coupled to single quadrupole Mass Spectrometry (MS) has been employed for the determination of volatile composition of smoked fish. Data processing consisted on the use of PARADISe software, applied for GC/MS data treatment, followed by the multivariate analysis with PLS_Toolbox (MATLAB), and finally the creation and validation of statistical classification model. All 107 variables obtained allowed the construction of a model reaching the correct classification of 97% of the blind samples, while a simplified model with only 11 variables correctly classified up to 93% of the blind samples. These 11 compounds were elucidated to develop subsequent target volatolomics approaches, if needed. Ordered according to the importance in the classification model, the elucidated compounds were: 3-methylcyclopentanone, ethylbenzene, 2-methyl-2-cyclopenten-1-one, 2-methyl-benzofuran, furfuryl alcohol, 2-acetylfuran, acetophenone, guaiacol, 1-hydroxy-2-butanone, 4-vinylguaicol and acetoin. The results demonstrated the great potential of untargeted volatolomics for smoked seafood treatments classification.

This work presents a strategy for elucidation of unknown migrants from plastic food contact materials (baby bottles) using a combination of analytical techniques in an untargeted approach. First, gas chromatography (GC) coupled to mass spectrometry (MS) in electron ionisation mode was used to identify migrants through spectral library matching. When no acceptable match was obtained, a second analysis by GC-(electron ionisation) high resolution mass spectrometry time of flight (TOF) was applied to obtain accurate mass fragmentation spectra and isotopic patterns. Databases were then searched to find a possible elemental composition for the unknown compounds. Finally, a GC hybrid quadrupole-TOF-MS with an atmospheric pressure chemical ionisation source was used to obtain the molecular ion or the protonated molecule. Accurate mass data also provided additional information on the fragmentation behaviour as two acquisition functions with different collision energies were available (MSE approach). In the low-energy function, limited fragmentation took place, whereas for the high-energy function, fragmentation was enhanced. For less volatile unknowns, ultra-high pressure liquid chromatography-quadrupole-TOF-MS was additionally applied. Using a home-made database containing common migrating compounds and plastic additives, tentative identification was made for several positive findings based on accurate mass of the (de)protonated molecule, product ion fragments and characteristic isotopic ions. Six illustrative examples are shown to demonstrate the modus operandi and the difficulties encountered during identification. The combination of these techniques was proven to be a powerful tool for the elucidation of unknown migrating compounds from plastic baby bottles. ; Federal Government Service for Public Health of Belgium through project: ALTPOLYCARB Generalitat Valenciana (Group of Excellence Prometeo) II/2014/023 ; ISIC/2012/016 Envi-Food

In this article, a dataset from a collaborative nontarget screening trial organised by the NORMAN Association is used to review the state-of-the-art and discuss future perspectives of non-target screening using high-resolution mass spectrometry in water analysis. A total of 18 institutes from 12 European countries analysed an extract of the same water sample collected from the River Danube with either one or both of liquid and gas chromatography coupled with mass spectrometry detection. This article focuses mainly on the use of high resolution screening techniques with target, suspect, and non-target workflows to identify substances in environmental samples. Specific examples are given to emphasise major challenges including isobaric and co-eluting substances, dependence on target and suspect lists, formula assignment, the use of retention information, and the confidence of identification. Approaches and methods applicable to unit resolution data are also discussed. Although most substances were identified using high resolution data with target and suspect-screening approaches, some participants proposed tentative non-target identifications. This comprehensive dataset revealed that nontarget analytical techniques are already substantially harmonised between the participants, but the data processing remains time-consuming. Although the objective of a Bfullyautomated identification workflow^ remains elusive in the short term, important steps in this direction have been taken, exemplified by the growing popularity of suspect screening approaches. Major recommendations to improve non-target screening include better integration and connection of desired features into software packages, the exchange of target and suspect lists, and the contribution of more spectra from standard substances into (openly accessible) databases. ; This work was supported in part by the SOLUTIONS project, which received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under Grant Agreement No. 603437.