Quantification of Arsenolipids in the Certified Reference Material NMIJ 7405-a (Hijiki) using HPLC/Mass Spectrometry after Chemical Derivatization

Abstract

Arsenic-containing lipids (arsenolipids) are novel natural products recently shown to be widespread in marine animals and algae. Research interest in these arsenic compounds lies in their possible role in the membrane chemistry of organisms and, because they occur in many popular seafoods, their human metabolism and toxicology. Progress has been restricted, however, by the lack of standard arsenolipids and of a quantitative method for their analysis. We report that the certified reference material CRM 7405-a (Hijiki) is a rich source of arsenolipids, and we describe a method based on HPLC-ICPMS/ESMS to quantitatively measure seven of the major arsenolipids present. Sample preparation involved extraction with DCM/methanol, a cleanup step with silica, and conversion of the (oxo)arsenolipids originally present to thio analogues by brief treatment with H2S. Compared to their oxo analogues, the thioarsenolipids showed much sharper peaks on reversed-phase HPLC, which facilitated their resolution and quantification. The compounds were determined by HPLC-ICPMS and HPLC-ESMS, which provided both arsenic-selective detection and high resolution molecular mass detection of the arsenolipids. In this way, the concentrations of two arsenic-containing hydrocarbons and five arsenosugar phospholipids are reported in the CRM Hijiki. This material may serve as a convenient source of characterized arsenolipids to delineate the presence of these compounds in seafoods and to facilitate research in a new era of arsenic biochemistry.

Environmental effects on arsenosugars and arsenolipids in Ectocarpus (Phaeophyta)

“…Formic acid (methanoic acid, HCO 2 H) and the chemicals for Provasoli-enriched sea water (b-glycerophosphate disodium salt hexahydrate (C 3 As As As As As As As As As…”

“…H 2 O 2 (0.4-2 mL) was added before microwave digestion (CEM MARS microwave, program: ramp to 50 8C; hold 5 min; ramp to 75 8C; hold 5 min; ramp to 95 8C; hold 30 min) and the samples were diluted (5-20 mL) after the microwave digestion. For totAs measurements of the different fractions: 1 mL of the water fraction was transferred to a 15-mL tube, 100 mL of MeOH and 200 mL of HNO 3 were added and diluted to 10 mL ready for totAs measurement (standards also prepared in MeOH and HNO 3 ). For the LS fraction, 50 mL of the concentrated MeOH fraction was transferred to 15-mL tubes, 0.2 mL HNO 3 was added and 0.4 mL H 2 O 2 added before microwave digestion.…”

“…À0.5 [3,11,12] and As-specific detection. Because of the similarities of AsLps found in Ectocarpus, Pylaiella and Elachista, all filamentous brown algae, and the identification in the cultures of the same main AsHC as found in the field-collected Ectocarpus, it can be assumed that similar AsPLs will be present in the cultures.…”

“…The St1 (E. crouaniorum) culture under oxidative stress conditions yielded the highest totAs in the water fraction owing to an increase in AsSugarSO 3 (Fig. 8a).…”

“…[1][2][3] Arsenic can be toxic and is known to be carcinogenic; however, the toxicity is species-dependent and varies between arsenic species. [4] A large quantity of naturally occurring organic forms of arsenic are formed from inorganic arsenic that is taken up from the environment.…”