Metals in sardine and anchovy from Greek coastal areas: Public health risk and nutritional benefits assessment.

Concentrations of 26 metals and elements were measured in sardine (Sardina pilchardus) and anchovy (Engraulis encrasicolus) sampled from 6 Greek coastal areas in order to assess public health risks and benefits. Nutritional benefits seem to outweigh the potential risks arising from fish metal content, since various parameters (Safety Standards, Estimated Daily Intake, Maximum Safe Consumption, Hazard Quotient, Metal Pollution Index, As Carcinogenic Risk, Mercury toxicity - Selenium benefits, Nutrient Reference Values) indicated mostly safe consumption of the studied species. Weekly consumption of 480.76 g of sardine and anchovy poses minor risks (due to increased levels of essential metals like Fe and Zn in some cases) but great benefits regarding intake of essential elements like Mg, Fe, Cu, Zn, Mo, Ca, P, Se. The traces of inorganic As detected were well below all safety limits. Hg toxicity symptoms are not likely to appear and Se benefits are not likely to be compromised.

LC-ICP-MS analysis of arsenic compounds in dominant seaweeds from the Thermaikos Gulf (Northern Aegean Sea, Greece).

The content of total arsenic and arsenic compounds in the dominant seaweed species in the Thermaikos Gulf, Northern Aegean Sea was determined in samples collected in different seasons. Total arsenic was determined by acid digestion followed by ICP-MS. Arsenic speciation was analyzed by water extraction followed by LC-ICP-MS. Total arsenic concentrations in the seaweeds ranged from 1.39 to 55.0 mg kg(-1). Cystoseira species and Codium fragile showed the highest total As contents, while Ulva species (U. intestinalis, U. rigida,U. fasciata) had the lowest Arsenosugars, the most common arsenic species in seaweeds, were found in all samples, and glycerol-arsenosugar was the most common form; however, phosphate-arsenosugar and sulfate-arsenosugar were also present. Inorganic arsenic was measured in seven algae species and detected in another. Arsenate was the most abundant species in Cystoseira barbata (27.0 mg kg(-1)). Arsenobetaine was measured in only one sample. Methylated arsenic species were measured at very low concentrations. The information should contribute to further understanding the presence of arsenic compounds in dominant seaweeds from the Thermaikos Gulf.

Development of mass spectrometric methods for detecting arsenic-glutathione complexes.

It has been suggested recently that arsenic-glutathione (As-GSH) complexes play an important role in the methylation of arsenic. The present study describes the development of high-performance liquid chromatography (HPLC)-electrospray tandem mass spectrometry (ES-MS/MS), operated in the selected reaction monitoring (SRM) mode, and HPLC-inductively coupled plasma mass spectrometry (ICP-MS) methods suitable for the sensitive and selective identification of four As-GSH complexes. Method optimization was carried out using a series of synthetically prepared standards, i.e., three As-GSH species containing trivalent arsenic: tri(glutamyl-cysteinyl-glycinyl)trithio-arsenite (ATG), di(glutamyl-cysteinyl-glycinyl)methyl-dithio-arsonite (MADG), and (ã-glutamyl-cysteinyl-glycinyl) dimethyl-thio-arsinite (DMAG), as well as one As-GSH species containing pentavalent As: dimethylthioarsinic acid-glutathione (DMTA(V)-GSH). The collision induced dissociation behavior of these compounds was investigated in detail to identify optimum SRM transitions for each complex. Both methods were based on reversed-phase chromatography using gradient elution with methanol, formic acid, and water as solvents. The amount of methanol that was used with this HPLC method (up to 12% vol/vol) was compatible with ICP-MS, without the need of a specially adapted interface. Subsequently, these analytical methods were applied to carry out a preliminary investigation about the role of As-GSH complexes in the methylation of arsenite by methylcobalamin (CH(3)B(12)) in the presence of glutathione (GSH). For the first time, the complexes ATG, MADG, and trace amounts of DMAG were detected as products of this reaction.

Identification of Sb(V) complexes in biological and food matrixes and their stibine formation efficiency during hydride generation with ICPMS detection.

Several studies have described the synthetic preparation of Sb(V) complexes with organic ligands, but only recently was such a complex identified to exist in beverages stored in PET containers. In the present study, we have investigated by using HPLC-ICPMS and HPLC-ES-MS(/MS), the formation of Sb(V) complexes in various biological (urine) and food matrixes (yoghurt and juice) spiked with noncomplexed inorganic Sb(V). Our results show that Sb(V) complex formation is matrix dependent and that several Sb(V) complexes form to a considerable extent in these matrixes. The results also suggest that the existence of Sb(V) complexes in natural samples may have previously been overlooked due to analytical method limitations, mainly chromatographic, but also detection limitations when hydride generation is used. To overcome some of these limitations, we have developed chromatographic methods suitable for preserving Sb-organic ligand complexes during their separation. When applying this mild nondestructive chromatographic method, we were able to identify novel Sb complexes in yoghurt spiked with inorganic Sb(V), i.e., 1:1 Sb(V)-citrate, 1:1 Sb(V)-lactate, 1:2 Sb(V)-lactate, and other Sb(V)-lactate complexes. This is the first characterization of Sb(V)-lactate complexes. Detailed studies on the hydride generation (HG) efficiency of Sb(V) complexes showed that Sb(V) complexes of high stability, such as Sb(V)-citrate, Sb(V)-(adenosine)n and Sb(V)-(lactate)n (n = 1 or 2), are nondetectable by HG-ICPMS. Furthermore, Sb(V) complexes formed in natural biological and food matrixes were only partly detectable by HG-ICPMS, confirming limitations of analytical methods based on HG volatilization and subsequent stibine detection in natural samples containing complexing ligands with affinity toward Sb(V).

Mass spectrometric identification and characterization of antimony complexes with ribose-containing biomolecules and an RNA oligomer.

Mass spectrometric techniques have been used to study the interaction of inorganic Sb(V) with biomolecules containing a ribose or deoxyribose moiety. Electrospray (ES) mass spectra of reaction mixtures containing inorganic Sb(V) and one of several biomolecules (adenosine, cytidine, guanosine, uridine, adenosine-5'-monophosphate, adenosine-3',5'-cyclic monophosphate, ribose, or 2'-deoxyadenosine) afforded high-mass antimony-containing ions corresponding to Sb(V)-biomolecule complexes of stoichiometry 1:1, 1:2, or 1:3. The complexes were characterized by collision-induced dissociation (CID) tandem mass spectrometry (MS) using ion-trap multistage MS. The CID results revealed that Sb(V) binds to the ribose or deoxyribose moiety. Structures are proposed for the Sb-biomolecule complexes. Analysis of the reaction mixtures by reversed-phase chromatography coupled on-line to either inductively coupled plasma (ICP) MS or ES-MS showed that in solution Sb(V) forms complexes with all the analyzed biomolecules with vicinal cis hydroxyl groups. Evidence (from size-exclusion chromatography ICP-MS and direct infusion ES-MS) of complexation of Sb(V) with an RNA oligomer, but not with a DNA oligomer, supports the suggestion that the presence of vicinal cis hydroxyl groups is critical for complexation to occur. This is the first direct evidence of complexation of Sb(V) with RNA. Results obtained by studying the effect of changing reaction conditions, i.e. pH, reaction time, and Sb/biomolecule molar ratio, on the extent of Sb-biomolecule formation suggest the reaction may be of physiological importance. Selected reaction monitoring (SRM) and precursor-ion-scanning tandem MS were investigated to determine their potential to detect trace levels of the Sb-biomolecule complexes in biological samples. Application of SRM MS-MS in combination with high-performance liquid chromatography enabled successful detection of an Sb-adenosine complex that had been spiked into a complex biological matrix (liver homogenate).

Arsenic compounds in the haemolymph of the Dungeness crab, Cancer magister, as determined by using HPLC on-line with inductively coupled plasma mass spectrometry.

Arsenobetaine, two arsenosugars, dimethylarsinate and several unidentified arsenic species were detected in extracts of the haemolymph of the Dungeness crab, Cancer magister, by using HPLC-ICP-MS. This is the first report of the presence of arsenosugars in the haemolymph/blood of marine animals. Total, extractable and residual arsenic concentrations were determined by ICP-MS. The concentration of total arsenic was in the range of 1.4-3.8 [micro sign]g ml(-1). Nearly all (98%) the arsenic was found to be extractable, and accounted for primarily by arsenobetaine, two arsenosugars and dimethylarsinate. The results demonstrate that arsenic compounds present in the diet of crabs are not fully metabolized in the gut. They are, at least partly, taken up into the haemolymph. The concurrence of arsenobetaine and arsenosugars suggests that the use of repeated haemolymph sampling in crustaceans could facilitate investigations into the kinetics of the biotransformation pathways of arsenic compounds. Finally, the present study clearly demonstrates the unique capabilities of HPLC-ICP-MS for the detection and identification of minor arsenic components amongst the predominant arsenobetaine.

Application of selected reaction monitoring tandem mass spectrometry to the quantitative determination of an arsenic-containing nucleoside in a crude biological extract.

HPLC electrospray selected reaction monitoring tandem mass spectrometry was used for the determination of a key arsenic metabolite, 5'-dimethylarsinoyladenosine, at trace levels (ca. 20 microg As l(-1)) in a crude extract of kidney from the clam Tridacna derasa.

Sequential hydride generation/pneumatic nebulisation inductively coupled plasma mass spectrometry for the fractionation of arsenic and selenium species.

The toxicity of certain elements is known to be related to their organic substituents and/or oxidation states. As such, total elemental determinations do not always yield sufficient information for accurate risk assessments and therefore speciation or fractionation data are required. In order to obtain fractionation data for trace levels of arsenic and selenium, a novel sequential pneumatic nebulisation (PN)/hydride generation (HG) inductively coupled plasma mass spectrometry (ICP-MS) method was developed. The method offers the advantage of sample introduction via either PN or HG by simply rotating a 4-way switching valve while the system is in operation. In PN mode, the liquid sample is aspirated into ICP, allowing for the determination of the total amount of each element, whilst in HG mode only the arsenic and selenium species that form volatile hydrides are determined. Conveniently, in the case of arsenic, this allows for differentiation between the four most toxic arsenic species (arsenate, arsenite, monomethylarsonic acid and dimethylarsinic acid), which form volatile hydrides, and the virtually non-toxic forms (arsenobetaine, arsenosugars, etc.), which do not. This allows for the rapid estimation of the amounts of toxic and non-toxic arsenic species present in a sample. For arsenic, the technique gave detection limits of 36 ng l(-1) in PN mode and 1 ng l(-1) in HG mode. For selenium, detection limits of 150 ng l(-1) were achieved in PN mode and 220 ng l(-1) in HG mode. The technique also gave good long- and short-term stabilities of under 6% RSD for both elements. A variety of samples, including water and urine standard reference materials, were analysed in both modes, and the precision and accuracy of the results for total arsenic and selenium levels were assessed. Using the technique in both modes also allowed for the fractionation of As and Se species into their volatile hydride-forming and non-hydride-forming species. This was particularly informative, with respect to As species present, in the case of a kelp powder extract. Digested tobacco samples were only analysed for their total As levels, in which case results obtained via both sample introduction modes showed good agreement.