Stepwise mass spectrometry-based approach for confirming the presence of benzoxazinoids in herbs and vegetables.

INTRODUCTION: Benzoxazinoids (BXs) are plant phytochemicals that have both defensive properties in plants and therapeutic effects in humans. The presence of BXs has been largely studied in the Poaceae family (monocots). To study the presence or absence of BXs in dicotyledons and monocotyledons outside the Poaceae family, parts of 24 plant species at several growth stages were selected for analysis, some of which were already known to contain BXs. OBJECTIVES: To devise a stepwise mass spectrometry-based approach for confirming the presence of BXs in plant samples, and to use the method to explore the status of BXs in selected plant species. EXPERIMENTAL: Plant samples were extracted using accelerated solvent extraction and analysed using triple-quadrupole liquid chromatography-mass spectrometry. RESULTS: The use of different columns, double mass transitions, and ion ratios proved to be a robust tool for confirming the presence of BXs in different plant species. By this method, the presence of BXs was confirmed in three of the 24 species. Double-hexose forms of BXs, which have not been reported before in dicotyledons, were confirmed to be present in the dicotyledon plants Acanthus mollis and Lamium galeobdolon, and the presence of BXs in the seeds of Consolida orientalis is reported for the first time here. High concentrations of BXs were found in the aerial parts of Acanthus mollis and Lamium galeobdolon, at 20 and 32 µmol/g plant dry weight, respectively. CONCLUSIONS: The stepwise approach described in this work confirmed the presence of BXs in new samples.

Microplastics in feed affect the toxicokinetics of persistent halogenated pollutants in Atlantic salmon.

Microplastics (MPs) are carriers of persistent organic pollutants (POPs). The influence of MPs on the toxicokinetics of POPs was investigated in a feeding experiment on Atlantic salmon (Salmo salar), in which fish were fed similar contaminant concentrations in feed with contaminants sorbed to MPs (Cont. MPs); feed with virgin MPs and contaminated feed (1:1), and feed with contaminants without MPs (Cont.). The results showed that the salmon fillets accumulated more POPs when fed with a diet where contaminants were sorbed to the MPs, despite the 125-250 µm size MPs themselves passing the intestines without absorption. Furthermore, depuration was significantly slower for several contaminants in fish fed the diet with POPs sorbed to the MPs. Modelled elimination coefficients and assimilation efficiencies of lipophilic chlorinated and brominated contaminants correlated with contaminant hydrophobicity (log Kow) within the diets and halogen classes. The more lipophilic the contaminant was, the higher was the transfer from feed to salmon fillet. The assimilation efficiency for the diet without MPs was 50-71% compared to 54-89% for the contaminated MPs diet. In addition, MPs caused a greater proportional uptake of higher molecular weight brominated congeners. In the present study, higher assimilation efficiencies and a significantly higher slope of assimilation efficiencies vs log Kow were found for the Cont. MPs diet (p = 0.029), indicating a proportionally higher uptake of higher-brominated congeners compared to the Cont. diet. Multiple variance analyses of elimination coefficients and assimilation efficiencies showed highly significant differences between the three diets for the chlorinated (p = 2E-06; 6E-04) and brominated (p = 5E-04; 4E-03) congeners and within their congeners. The perfluorinated POPs showed low assimilation efficiencies of <12%, which can be explained by faster eliminations corresponding to half-lives of 11-39 days, as well as a lower proportional distribution to the fillet, compared to e.g. the liver.

Detection of Nitrated, Oxygenated and Hydrogenated Polycyclic Aromatic Compounds in Smoked Fish and Meat Products.

Polycyclic aromatic hydrocarbons (PAHs) are present in smoked food products. More toxic nitrated (NPAH) and oxygenated (OPAH) PAHs derivatives are found concomitantly to PAHs and are therefore believed to be found in smoked food products. However, only a few PAH analyses on food include these derivatives. We adjusted and successfully validated a GC-QTOFMS method including 13 NPAHs and 2 OPAHs as well as the 4 regulated PAHs for analysis of 14 smoked (13 fish and one bacon) and one pan fried fish samples.OPAHs were detected in the highest concentrations in 13 of 15 samples. Non-target screening revealed the presence of an additional four OPAHs and two methylated PAHs. Future food analysis should, based on these results, focus on PAH and oxygenated derivatives.