1,721,034 research outputs found
An innovative method based on quick, easy, cheap, effective, rugged, and safe extraction coupled to desorption electrospray ionization-high resolution mass spectrometry for screening the presence of paralytic shellfish toxins in clams
Full text linkThe capabilities of desorption electrospray ionization-high resolution mass spectrometry (DESI-HRMS)
were tested for screening the presence of some paralytic shellfish toxins in clams. A quick, easy, cheap,
effective, rugged, and safe (QuEChERS) approach is proposed for sample clean-up.QuEChERS extraction
was optimized by using a full factorial design followed by the multicriteria method of the desirability
functions. Quantitation limits in the microgram pe rkilogram range proved reliability of the method for
the detection of the investigated toxins in accordance to the rules laid down by European legislation. The
optimized QuEChERS-DESI-HRMS based-method allowed for a rapid reliable screening of the in-
vestigated compounds at levels of interest, thus being useful for high-throughput analyse
Experimental design for the optimization of the extraction conditions of polycyclic aromatic hydrocarbons in milk with a novel diethoxydiphenylsilane solid-phase microextraction fiber
No full textAptamer-based assays: strategies in the use of aptamers conjugated to magnetic micro- and nanobeads as recognition elements in food control
Full text linkAn outlook on the current status of different strategies for magnetic micro- and nanosized bead functionalization with aptamers as prominent bioreceptors is given with a focus on electrochemical and optical apta-assays, as well as on aptamer-modified magnetic bead-based miniaturized extraction techniques in food control. Critical aspects that affect interaction of aptamers with target molecules, as well as the possible side effects caused by aptamer interaction with other molecules due to non-specific binding, are discussed. Challenges concerning the real potential and limitations of aptamers as bioreceptors when facing analytical problems in food control are addressed
Rapid desorption electrospray ionization-high resolution mass spectrometry method for the analysis of melamine migration from melamine tableware
No full textMigration of melamine into foods from melamine tableware has been object of recent Rapid Alert System for Food and Feed (RASFF) notifications. In this context, a rapid and sensitive desorption electrospray ionization-high resolution mass spectrometry (DESI-HRMS) method was developed and
validated for the determination of melamine migration from plastic materials. The migration test was performed using acetic acid 3% (w/v) as food simulant.
Evaluation of DESI parameters in terms of choice of support, motion profile, geometrical configuration and operating conditions coupled to the use of an orbitrap mass analyzer allowed to achieve significant improvements in terms of selectivity and accuracy obtaining detection and quantitation limits at low microgram per kilogram level. A LC–ESI-MS method was also developed for confirmatory purposes. Both methods were applied to 44 melamine tableware samples available on Italian market in order to assess their compliance with the law. Different concentration levels ranging from 0.0077370.0006 to
3.070.1 mg/kg were found after the third exposure to the simulant in new and used tableware with two samples out of 44 being characterized by a melamine release higher than the legal limit, i.e. 2.5 mg/kg. A two tailed t-test allowed to assess the good agreement between the quantitative results obtained
applying the DESI-MS method with those provided by LC–ESI-MS, thus proving reliability of DESIHRMS as rapid technique for the study of melamine release from plastic materials
Rapid Shotgun Proteomic Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry-Based Method for the Lupin (Lupinus albus L.) Multi-allergen Determination in Foods
No full textAllergy to lupin is a growing food safety problem because this legume, increasingly exploited in the food industry, is one of the allergens that, according to law, must be declared on the labels of food products in the European Union. In this context, a rapid targeted proteomic approach based on liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) analysis was proposed and aimed to unequivocal confirmation and reliable determination of the major lupin allergens, i.e., conglutins, in pasta and biscuits. Detected concentrations were around 1 mg of lupin/kg of pasta and biscuits, proving the capabilities of the MS-based method in terms of the sensitive allergen screening method. Good precision was observed in terms of both intra-and interday repeatability, with relative standard deviation (RSD) lower than 23%. Recoveries from 95 +/- 10 to 118 +/- 12% and from 103 +/- 1 to 110 +/- 12% ranges were calculated for biscuits and pasta, respectively. Finally, the applicability of the devised method was investigated by analyzing market samples containing lupin and samples that may possibly contain traces of lupin deriving from cross-contamination between products and production lines
Multiplex liquid chromatography-tandem mass spectrometry for the detection of wheat, oat, barley and rye prolamins towards the assessment of gluten-free product safety
Full text linkCeliac patients should feel confident in the safety of foods labelled or expected to be gluten-free. In this context, a targeted proteomic approach based on liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) technique was proposed to assess the presence of celiotoxic cereals, namely wheat, oats, barley and rye, in raw and processed food products. To this aim, unique marker peptides were properly selected in order to distinguish between the different cereal types. A revised cocktail solution based on reducing and denaturing agents was exploited for prolamin extraction from raw and processed food; in addition, defatting with hexane was carried out for sample clean-up, allowing to largely reduce problems related to matrix effect. Method validation on fortified rice flour showed good analytical performance in terms of sensitivity (limits of detection in the 2-18 mg kg(-1) range). However, poor trueness was calculated for self-made incurred bread (between 3 and 30% depending on the peptide), probably due to baking processes, which reduce gluten extractability. Thus, it is evident that in the case of processed foods further insights into sample treatment efficiency and reference materials for protein calibration are required to obtain accurate gluten determination. Finally, the developed method was applied for the analysis of market food products, offering the possibility to discriminate among cereals, with good agreement with labelled ingredients for gluten-containing foodstuffs
Liquid Chromatography/Mass Spectrometry in Environmental Analysis
No full textLiquid chromatography/mass spectrometry (LC-MS) technique enables analysis of emergent polar compounds without the need for derivatization reaction, while the introduction of high-resolution mass analyzers in hybrid configurations makes possible to elucidate chemical structure, also without reference standards. Over the past 10 years, besides target analysis, the coupling of LC to high-resolution mass spectrometry (HRMS) has allowed screening of compounds expected to be in the environment, as well as nontarget screening of unknown compounds, such as transformation products (TPs) formed in the environment or during technical wastewater and sewage purification treatments. Nowadays, analytical chemists are trying to achieve real nontarget analysis of numerous unknowns in environmental samples for a comprehensive view of the true overall contamination present in samples, but it still remains a very challenging issue. The development of new software tools to extract relevant data, spectra libraries, and databases will be of great help to solve this issue, enhancing the success rate.
This article represents the second edition of a previous manuscript by Careri,2000 which was updated to take into account the huge progress in MS instrumentation and related methodologies and also advances in environmental analytical chemistry. In this overview, among the environmental applications of LC-MS, current and innovative approaches for the analysis of selected classes of emerging pollutants, such as novel brominated flame retardants, nanomaterials, hormones and other endocrine disruptors, and pharmaceutical and personal care products in environmental samples are discussed
ESEM-EDS: In vivo characterization of the Ni hyperaccumulator Noccaea caerulescens
No full textEnvironmental scanning electron microscopy (ESEM) permits to analyze samples in their native-hydratedstate, allowing a broad spectrum of biological applications. In this study, ESEM equipped with energydispersive X-ray spectrometer (EDS) was used as a fast method to analyze tissue morphology and toinvestigate metal distribution in the Ni hyperaccumulator Noccaea caerulescens, an established model tostudy the adaptation of plants to metalliferous soils. The low vacuum and wet mode operative conditionsrequired the proper choice of experimental parameters both for morphological and compositional char-acterization of plant tissues. The calibration strategy for semi-quantitative analysis involved the use ofNi fortified agar as standard and signal normalization respect to endogenous carbon, chosen as internalstandard. The obtained results are in accordance with present literature, showing a preferential Ni dis-tribution in the epidermal cells respect to near the stomata for leaves and in the cotyledon epidermidisrespect to cotyledon parenchyma area for seeds. Thanks to the absence of any time consuming sampletreatment steps, ESEM-EDS technique can be proposed as valid strategy for in vivo high-throughput anal-ysis of plant tissues and for a rapid screening and identification of other hyperaccumulator plants in aselected contaminated area
Novel coating for solid-phase microextraction: electropolymerization of a molecular receptor functionalized with 2,2’-bithiophene for the determination of environmental pollutants at trace levels
No full textA novel solid-phase microextraction coating based on the electropolymerization of a molecular receptor
properly functionalized with 2,2-bithiophene was developed for the determination of environmental
pollutants in air and water samples. The 2,2-bithiophene-based film was electrochemically deposed on
the surface of a gold wire using cyclic voltammetry. The fibres showed a porous structure with an average
thickness of 12±3m (n = 5): a good intra-batch and inter-batch repeatability with RSD lower than 14%
was also observed. The selective interactions via hydrogen bonding with organic molecules containing
electronegative atoms was proved: LOD values in the low ng/l range allowed the determination of vinyl
chloride and chlorobenzenes at trace levels in environmental matrices
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