SciCombinator

Discover the most talked about and latest scientific content & concepts.

Journal: Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment

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In order to confirm the possibility that recycled fractions from the Waste Electrical and Electronic Equipment (WEEE) stream were illegally entering the European market in black polymeric food-contact articles (FCAs), bromine quantification, brominated flame retardant (BFR) identification combined with WEEE relevant elemental analysis and polymer impurity analysis were performed. From the 10 selected FCAs, seven samples contained a bromine level ranging from 57 till 5975 mg kg(-1) which is lower than expected to achieve flame retardancy. The BFRs which were present were tetrabromobisphenol A (TBBPA), decabromodiphenylether (decaBDE), decabromodiphenylethane (DBDPE) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE). Typical elements used in electronic equipment and present in WEEE were detected either at trace level or at elevated concentrations. In all cases when bromine was detected at higher concentrations, concurrently antimony was also detected which confirms the synergetic use of antimony in combination with BFRs. This study describes also the measurement of rare earth elements (REEs) where combinations of cerium, dysprosium, lanthanum, neodymium, praseodymium and yttrium which were detected in four of the seven BFR positive samples. Additionally, the polymer purity was investigated where in all cases foreign polymer fractions were detected. Despite the fact that this study was carried-out on a very small amount of samples there is a significant likelihood that WEEE has been used for the production of FCAs.

Concepts: Flame retardant, Rare earth element, Chemical elements, Yttrium, Brominated flame retardant, Cerium, Lanthanide, Monazite

28

A new method combining QuEChERS (quick, easy, cheap, effective, rugged and safe) and DLLME (dispersive liquid-liquid microextraction) followed by gas chromatography-mass spectrometry with selected ion monitoring (SIM) was developed for the simultaneous determination of 19 pesticides from nine chemical groups exhibiting or suspected to exhibit endocrine-disrupting properties in orange samples. Acetonitrile extract obtained from QuEChERS extraction was used for DLLME as dispersive solvent and carbon tetrachloride as extractive solvent to increase the enrichment factor of the extraction procedure. The effect of several extraction parameters, such as volume extract achieved by the QuEChERS method and subsequently used for DLLME, selection of extractive solvent and its volume, was tested. Under optimum conditions, good linearity, satisfactory recoveries and repeatability were obtained. Limits of quantification (LOQs) achieved (ranging from 0.02 to 47 ng/g) were below the maximum residue limits established by the European Union. The proposed method was applied to the monitoring of pesticide residue levels in oranges commercialised in Portugal.

Concepts: European Union, Mass spectrometry, Effectiveness, Portugal, Pesticide, Soil contamination, Pesticide residue, Pesticides

28

The caffeine content of 124 products, including coffee, coffee-based beverages, energy drinks, tea, colas, yoghurt and chocolate, were determined using RP-HPLC with UV detection after solid-phase extraction. Highest concentrations of caffeine were found for coffee prepared from pads (755 mg l(-1)) and regular filtered coffee (659 mg l(-1)). The total caffeine content of coffee and chocolate-based beverages was between 15 mg l(-1) in chocolate milk and 448 mg l(-1) in canned ice coffee. For energy drinks the caffeine content varied in a range from 266 to 340 mg l(-1). Caffeine concentrations in tea and ice teas were between 13 and 183 mg l(-1). Coffee-flavoured yoghurts ranged from 33 to 48 mg kg(-1). The caffeine concentration in chocolate and chocolate bars was between 17 mg kg(-1) in whole milk chocolate and 551 mg kg(-1) in a chocolate with coffee filling. A caffeine assessment tool was developed and validated by a 3-day dietary record (r (2 )= 0.817, p < 0.01) using these analytical data and caffeine saliva concentrations (r (2 )= 0.427, p < 0.01).

Concepts: Milk, Coffee, Caffeine, Tea, Drink, Chocolate, Kefir, Chocolate milk

28

Sulfites are routinely added as preservatives and antioxidants in wine production. By law, the total sulfur dioxide content in wine is restricted and therefore must be monitored. Currently, the method of choice for determining the total content of sulfur dioxide in wine is the optimised Monier-Williams method, which is time consuming and laborious. The headspace gas chromatographic method described in this study offers a fast and reliable alternative method for the detection and quantification of the sulfur dioxide content in wine. The analysis was performed using an automatic headspace injection sampler, coupled with a gas chromatograph and an electron capture detector. The method is based on the formation of gaseous sulfur dioxide subsequent to acidification and heating of the sample. In addition to free sulfur dioxide, reversibly bound sulfur dioxide in carbonyl compounds, such as acetaldehyde, was also measured with this method. A total of 20 wine samples produced using diverse grape varieties and vintages of varied provenance were analysed using the new method. For reference and comparison purposes, 10 of the results obtained by the proposed method were compared with those acquired by the optimised Monier-Williams method. Overall, the results from the headspace analysis showed good correlation (R = 0.9985) when compared with the conventional method. This new method requires minimal sample preparation and is simple to perform, and the analysis can also be completed within a short period of time.

Concepts: Oxygen, Chromatography, Gas chromatography, Wine, Sulfur dioxide, Sulfite, Electron capture detector, Chromatography software

28

Deoxynivalenol, T-2 and HT-2 toxins are mycotoxins frequently occurring in cereals and cereal-based products along with their conjugated forms. In this paper, we provide insights into the fate of deoxynivalenol, T-2 and HT-2 toxins and their glucoside derivatives during bread making, using naturally contaminated wheat flour. High-resolution mass spectrometry was used to assess the extent of degradation of the three mycotoxins during bread baking and to identify some glucoside conjugates, namely deoxynivalenol, T-2 and HT-2 mono-glucosides, detected both in the flour and in the respective breads. Our findings show deoxynivalenol’s levels markedly increased upon baking, whereas those of HT-2 and T-2 toxins were decreased in the final bread with special regard to the T-2 toxin.

Concepts: Wheat, Chromatography, High performance liquid chromatography, Bread, Rye, Flour, Staple food, Cake

27

For future targeted screening in National Residue Control Programmes, the metabolism of seven SARMs, from the arylpropionamide and the quinolinone classes, was studied in vitro using S9 bovine liver enzymes. Metabolites were detected and identified with ultra-performance liquid chromatography (UPLC) coupled to time-of-flight mass spectrometry (ToF-MS) and triple quadrupole mass spectrometry (QqQ-MS). Several metabolites were identified and results were compared with literature data on metabolism using a human cell line. Monohydroxylation, nitro-reduction, dephenylation and demethylation were the main S9 in vitro metabolic routes established. Next, an in vivo study was performed by oral administration of the arylpropionamide ostarine to a male calf and urine samples were analysed with UPLC-QToF-MS. Apart from two metabolites resulting from hydroxylation and dephenylation that were also observed in the in vitro study, the bovine in vivo metabolites of ostarine resulted in glucuronidation, sulfation and carboxylation, combined with either a hydroxylation or a dephenylation step. As the intact mother compounds of all SARMs tested are the main compounds present after in vitro incubations, and ostarine is still clearly present in the urine after the in vivo metabolism study in veal calves, the intact mother molecules were selected as the indicator to reveal treatment. The analytical UPLC-QqQ-MS/MS procedure was validated for three commercially available arylpropionamides according to European Union criteria (Commission Decision 2002/657/EC), and resulted in decision limits ranging from 0.025 to 0.05 µg l(-1) and a detection capability of 0.025 µg l(-1) in all cases. Adequate precision and intra-laboratory reproducibility (relative standard deviation below 20%) were obtained for all SARMs and the linearity was 0.999 for all compounds. This newly developed method is sensitive and robust, and therefore useful for confirmation and quantification of SARMs in bovine urine samples for residue control programmes and research purposes.

Concepts: Protein, Metabolism, Mass spectrometry, In vivo, In vitro, Quadrupole mass analyzer, Calf, Selective androgen receptor modulator

27

This article describes the production of an anti-citrinin antibody that showed a high affinity constant (Ka) of 6.28 × 10(9) and good tolerance to organic solvent and low pH, the synthesis of a Cu (II)-embedded polymer that showed strong binding with this antibody and the preparation of packing material for an immunoaffinity column (IAC) that show good stability. Most of the IACs reported either use harsh elution conditions and are used only once or use gentle elution conditions and are reused many times. Here, through the combined use of a strong-affinity antibody and packing material with good stability, high recoveries during clean-up and yet simultaneously good stability of the IAC were successfully achieved. Under optimised conditions of 80% methanol (pH 3), the IACs were used to clean-up the extracts of Monascus colour and red yeast rice samples, followed by HPLC detection. The recoveries of citrinin from spiked samples at levels of 50-200 μg kg(-1) were in the range of 84-97%.

Concepts: Ethanol, Acid dissociation constant, PH, Acetic acid, Solvent, Methanol, Red yeast rice, Monascus purpureus

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Ciguatera fish poisoning is a seafood intoxication commonly afflicting island communities in the Pacific. These populations, which are strongly dependent on fish resources, have developed over centuries various strategies to decrease the risk of intoxication, including the use of folk tests to detect ciguateric fish. This study aims to evaluate the effectiveness of two folk tests commonly used in Raivavae Island (Australes, French Polynesia): the rigor mortis test (RMT) and the bleeding test (BT). A total of 107 fish were collected in Raivavae Lagoon, among which 80 were tested by five testers using the RMT versus 107 tested by four testers using BT. First, the performance between testers was compared. Second, the efficiency of these tests was compared with toxicity data obtained via the receptor binding assay (RBA) by assessing various parameter’s values such as sensitivity (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV). Comparisons of outcomes between folk tests and RBA analyses were considered: tests used separately or in a parallel versus the series approach by each tester. The overall efficiency of the RMT and BT tests was also evaluated when the judgments of all testers were “pooled”. The results demonstrate that efficiencies varied between testers with one showing the best scores in detecting toxic fish: 55% with RMT and 69.2% with BT. BT gave the best results in detecting toxic fish as compared with RMT, giving also better agreement between testers. If high NPV and Se values were to be privileged, the data also suggest that the best way to limit cases of intoxication would be to use RMT and BT tests in a parallel approach. The use of traditional knowledge and a good knowledge of risky versus healthy fishing areas may help reduce the risk of intoxication among communities where ciguatera fish poisoning is highly prevalent.

Concepts: Positive predictive value, Negative predictive value, Sensitivity and specificity, Pacific Ocean, Seafood, Andrew Martin, Rigor mortis, Ciguatera

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Ciguatera fish poisoning (CFP), a disease caused by consuming fish that have accumulated ciguatoxins (CTXs) in their tissue, is regarded as the most prevalent form of intoxication in French Polynesia. Recently, the Australes, one of the least affected archipelago until the early 1980s, has shown a dramatic increase in its incidence rates in 2009 with unusual CFP cases. In the present work, potential health hazards associated with the proliferation of various marine phytoplankton species and the consumption of fish and marine invertebrates highly popular among local population were assessed in three Australes islands: Raivavae, Rurutu and Rapa. Extracts from the marine dinoflagellates Gambierdiscus, Ostreospis and mat-forming cyanobacteria as well as fish, giant clams and sea urchin samples were examined for the presence of CTXs and palytoxin (PLTX) by using the neuroblastoma cell-based assay (CBA-N2a). Cytotoxic responses observed with both standards (Pacific CTX-3C and PLTX) and targeted marine products indicate that CBA-N2a is a robust screening tool, with high sensitivity and good repeatability and reproducibility. In Rurutu and Raivavae islands, our main findings concern the presence of CTX-like compounds in giant clams and sea urchins, suggesting a second bio-accumulation route for CFP toxins in the ciguatera food chain. In Rapa, the potential CFP risk from Gambierdiscus bloom and fish was confirmed for the first time, with levels of CTXs found above the consumer advisory level of 0.01 ng Pacific CTX-1B g(-1) of flesh in three fish samples. However, despite the presence of trace level of PLTX in Ostreopsis natural assemblages of Rapa, no sign of PLTX accumulation is yet observed in tested fish samples. Because this multi-toxinic context is likely to emerge in most French Polynesian islands, CBA-N2a shows great potential for future applications in the algal- and toxin-based field monitoring programmes currently on hand locally.

Concepts: Pacific Ocean, Algal bloom, Dinoflagellate, Sea urchin, French Polynesia, Polynesia, Austral Islands, Ciguatera

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A qualitative and quantitative determination method for chloropropanols in soy sauce was developed by GC-MS/MS with coupled column separation without derivatisation. The target compounds were 1,3-dichloropropan-2-ol (1,3-DCP), 2,3-dichloropropan-1-ol (2,3-DCP), 3-monochloropropane-1,2-diol (3-MCPD) and 2-monochloropropane-1,3-diol (2-MCPD). 3-MCPD-d(5) was used as an isotope internal standard for MCPDs and 1,3-DCP-d(5) for DCPs. After spiking with internal standards and mixed with 1 g of Extrelut™ NT, about 1 g of the sample was washed by 4 ml of hexane and the analytes were eluted with 15 ml of 95% (v/v) ethyl ether/hexane mixture. The concentrated extract was directly injected without derivatisation, separated by a coupled column - a 3 m Innowax (polyethylene glycol) combined with a 30 m DB-5 ms ((5%-phenyl)-methylpolysiloxane) by a quartz capillary column connector - and detected by GC-MS/MS. The limits of detection (LODs) in the sample matrix were 1.0, 2.5, 5.0 and 5.0 µg kg(-1) for the above chloropropanols, respectively. The relative proportions of 2-MCPD/3-MCPD ranged from 0.19 to 3.74 in soy sauce samples. 2,3-DCP and 2-MCPD were more stable than 1,3-DCP and 3-MCPD under alkaline condition. The levels of chloropropanols can be decreased by an alkaline treatment process.

Concepts: Mass spectrometry, Analytical chemistry, Qualitative research, Quadrupole mass analyzer, Separated sets, Separation axiom, 3-MCPD, Condiment