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Environmental context: The marine ecosystem is highly elevated in arsenic in comparison to the terrestrial environment. More than 100 different naturally occurring organoarsenic compounds have been found in different marine organisms. In order to understand how highly toxic AsHCs are formed and bioaccumulate in different marine organisms, large scale monitoring of AsHCs from a range of different laboratories is necessary. Despite their toxicity, AsHCs have not been extensively studied due in part to the lack of low-cost analytical methods and the lack of commercially available standards. Rational: This study aims to develop a new analytical method for the quantitative determination of arsenic-containing hydrocarbons (AsHCs) with gas chromatography–mass spectrometry (GC-MS). The new method is an alternative approach to determine these compounds in environmental samples. Methodology: AsHCs were extracted and purified from fish oil and seaweed samples. Due to the thermal conversion of oxo-AsHCs to their trivalent forms in the injection port of the GC, the conversion is incomplete resulting in low signal intensities and large carry overs. We therefore chemically reduced AsHCs to their trivalent forms and analysed them with GC-MS, gas chromatography–tandem mass spectrometry (GC-MS/MS) and high performance liquid chromatography–inductively coupled plasma mass spectrometry (HPLC-ICPMS). The possibility for compound independent quantification with commercially available standards was investigated. Results: After optimisation of conditions for reduction of AsHCs, these compounds could be determined in marine samples using authentic standards with the new method. Results showed good agreement with results from HPLC-ICPMS. The novel GC-MS method showed compound independent quantification using triphenylarsine (TPA) as a commercially available standard. Discussion: With the developed method we could demonstrate the applicability of GC-MS for the quantitative determination of AsHCs in marine samples for the first time. The compound independent quantification with TPA opens up a quantification for AsHCs species for which no standards are commercially available. The broad applicability might enhance screening for these toxic compounds in the environment. Environmental context. The marine ecosystem is highly elevated in arsenic in comparison to the terrestrial environment. More than 100 different naturally occurring organoarsenic compounds have been found in different marine organisms. In order to understand how highly toxic AsHCs are formed and bioaccumulate in different marine organisms, large scale monitoring of AsHCs from a range of different laboratories is necessary. Despite their toxicity, AsHCs have not been extensively studied due in part to the lack of low-cost analytical methods and the lack of commercially available standards. [ABSTRACT FROM AUTHOR]

Environmental context: Arsenic can be found in all environmental compartments in a large number of chemical forms of varying toxicity. We performed an inter-laboratory comparison study focusing on quantitation of some of the most toxic arsenic forms in seven different biological materials and found very good agreement among the submitted results. Certification of the studied materials will provide suitable quality control samples for environmentally relevant concentrations of arsenic in food products and biota. Rationale: Arsenic (As) speciation analysis in biological matrices has been performed for several decades; however, there are very few matrix certified reference materials available for the validation of analytical methods. The literature data on the mass fractions of As species in the existing certified reference materials are inconsistent and suggest method extraction dependency. Methodology: In the present study, an international round-robin study was organised to identify the possible sources of discrepancies in quantitation of several As species in different matrices of biological reference materials: one plant tissue, three marine and three terrestrial biological tissues. Each participating laboratory was provided with a set of identical calibration standard solutions, and analysed the samples by following a common group extraction method as well as using an in-house protocol. Results: The results showed that significant biases can be introduced by insufficient verification of the analyte's mass fractions in the calibration standard solutions. The choice of extraction method seems to have very little impact on the quantitation of As species in the studied plant and terrestrial biological tissues. However, following a prescribed extraction method led to significant reduction of uncertainties in more complex samples such as marine animal tissues. Discussion: Some differences in the mass fractions of As species extracted from marine animal tissues in water (with and without H2O2) were observed and should be further investigated. Despite the variety of extraction methods used, very good agreement between reported mass fractions was achieved and the combined consensus values will be published as certified reference values of As species in the studied materials. Environmental context. Arsenic can be found in all environmental compartments in a large number of chemical forms of varying toxicity. We performed an inter-laboratory comparison study focusing on quantitation of some of the most toxic arsenic forms in seven different biological materials and found very good agreement among the submitted results. Certification of the studied materials will provide suitable quality control samples for environmentally relevant concentrations of arsenic in food products and biota. [ABSTRACT FROM AUTHOR]

Although Kevin determined the fish arsenic in a crustacean (Western Rock Lobster), arsenobetaine was later established as the main organoarsenic compound in fish and shellfish. Both papers make arsenic speciation analysis more transparent and democratic, and enhance the proficiency of arsenic species determination, absolutely in line with Kevin's passion for only the best analytical chemistry. A whole generation of environmental analytical chemists interested in arsenic speciation relied (and still relies) on Kevin's talented hands (yes, Kevin was still active in the lab himself) to produce some complex organoarsenicals as standards, which were either isolated from marine organisms or synthesised (e.g. [11]). I am honoured to have been asked to organise a special issue for Professor Kevin A. Francesconi, a towering figure in environmental chemistry, who retired a few years ago from his leading role as Professor for Analytical Chemistry at the University of Graz in Austria. [Extracted from the article]

Environmental context: Arsenic contamination has a disproportionate effect on marine ecosystems. Organisms such as some marine macroalgae, which accumulate potentially toxic elements from the surrounding environment, have developed an internal conversion process that is not yet fully understood. Are arsenic-containing sugars a product of detoxification, or simply the result of phospholipid degradation? Rationale: Arsenosugars (AsSugar) account for the majority of total arsenic in common seaweed species, yet it is unclear whether these are formed through some detoxification pathway for inorganic arsenic or are precursors/degradation products of arsenic-containing phospholipids in the cell wall. Methodology: Temporal and intra-thallus variations in water-soluble arsenic were measured by HPLC-ICP-MS, as well as total non-polar and polar arsenic-containing lipids by ICP-MS in Laminaria digitata to offer potential insight into the origins of arsenosugars. Water-soluble speciation with and without freeze-drying were also compared to determine whether freeze-drying changes the water-soluble As speciation. Results: In general, lower levels of total As were detected in the samples collected in May (39.2–74.5 mg kg−1) compared to those collected in February (72.6–151 mg kg−1). The concentration of arsenate was found to consistently increase along the thallus from the holdfast/stipe (0.78–1.82 mg kg−1) to the decaying fronds (44.4–61.0 mg kg−1) in both months, and AsSug-SO3 was the dominant AsSugar in the majority of samples. The extraction efficiency was lower in fresh samples (64–77%) than in freeze-dried (95–116%) from the same month. Water-soluble, polar AsLipids, and residual As concentrations, were generally highest in February, and the non-polar AsLipids accounted for <0.42% of totAs in all samples. Discussion: Our results suggest that the arsenosugars are not a product of arsenic detoxification, but a by-product of normal biological activity. It is probable that the arsenosugars are bound to the cell membrane within the Laminaria digitata cells, and lyophilisation is required to release them quantitatively. Future research should focus on speciation of polar lipid-soluble As extracted from fresh samples to determine if the lower extraction efficiency observed in this study is due to the As being in an unextractable form, i.e. lipids, and thus is not removed from cells during water-based extractions. Environmental context. Arsenic contamination has a disproportionate effect on marine ecosystems. Organisms such as some marine macroalgae, which accumulate potentially toxic elements from the surrounding environment, have developed an internal conversion process that is not yet fully understood. Are arsenic-containing sugars a product of detoxification, or simply the result of phospholipid degradation? [ABSTRACT FROM AUTHOR]