Two-dimensional HPLC coupled to ICP-MS and electrospray ionisation (ESI)-MS/MS for investigating the bioavailability in vitro of arsenic species from edible seaweed.

Edible seaweed consumption is a route of exposure to arsenic. However, little attention has been paid to estimate the bioaccessibility and/or bioavailability of arsenosugars in edible seaweed and their possible degradation products during gastrointestinal digestion. This work presents first use of combined inductively coupled plasma mass spectroscopy (ICP-MS) with electrospray ionization tandem mass spectrometry (ESI-MS/MS) with two-dimensional HPLC (size exclusion followed by anion exchange) to compare the qualitative and quantitative arsenosugars speciation of different edible seaweed with that of their bioavailable fraction as obtained using an in vitro gastrointestinal digestion procedure.

Evaluation of an in vitro method to estimate trace elements bioavailability in edible seaweeds.

Raw edible seaweed harvested in the Galician coast (Northwestern Spain), including two red seaweed types (Dulse and Nori), three brown seaweed (Kombu, Wakame and Sea Spaghetti), one green seaweed (Sea Lettuce) and one microalgae (Spirulina platensis) were studied to assess trace elements bioavailability using an in vitro method (simulated gastric and intestinal digestion/dialysis). Similarly, a cooked seaweed sample (canned in brine) consisting of a mixture of two brown seaweed (Sea Spaghetti and Furbelows) and a derived product (Agar-Agar) from the red seaweed Gelidiumm sesquipedale, were also included in the study. The total trace element content as well as the non-dialyzable fractions was carried out after a microwave acid digestion of the seaweed samples by inductively coupled plasma-mass spectrometry (ICP-MS).

Characterization of raft mussels according to total trace elements and trace elements bound to metallothionein-like proteins.

In the current work, samples of Mytilus galloprovincialis collected in different sites from Ría de Arousa estuary (Galicia, north-western Spain) were analysed for total Al, As, Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn, and for Ba, Cu, Mn and Zn bound to metallothionein-like proteins isoform I (MLP-I) contents. Inductively coupled plasma-optical emission spectrometry (ICP-OES) was used to assess total metal contents in raft mussels, while high performance liquid chromatography (HPLC) with an on-line metal detection with ICP-OES was used to measure metals bound to MLP-I. A microwave assisted acid digestion procedure was used as a sample pre-treatment for total metal contents, while a cytosolic preparation method based on a blending procedure with TRIS-HCl (pH 7.