title: A microwave-assisted sequential extraction of water and dilute acid soluble arsenic species from marine plant and animal tissues.
abstract: This paper describes the use of dilute nitric acid for the extraction and quantification of arsenic species. A number of extractants (e.g. water, 1.5M orthophosphoric acid, methanol-water and dilute nitric acid) were tested for the extraction of arsenic from marine biological samples, such as plants that have proved difficult to quantitatively extract. Dilute 2% (v/v) nitric acid was found to give the highest recoveries of arsenic overall and was chosen for further optimisation. The optimal extraction conditions for arsenic were 2% (v/v) HNO(3), 6 min(-1), 90 degrees C. Arsenic species were found to be stable under the optimised conditions with the exception of the arsenoriboses which degraded to a product eluting at the same retention time as glycerol arsenoribose. Good agreement was found between the 2% (v/v) HNO(3) extraction and the methanol-water extraction for the certified reference material DORM-2 (AB 17.1 and 16.2microg g(-1), respectively, and TETRA 0.27 and 0.25microg g(-1), respectively), which were in close agreement with the certified concentrations of AB 16.4+/-1.1microg g(-1) and TETRA 0.248+/-0.054microg g(-1). To preserve the integrity of arsenic species, a sequential extraction technique was developed where the previously methanol-water extracted pellet was further extracted with 2% (v/v) HNO(3) under the optimised conditions. Increases in arsenic recoveries between 13% and 36% were found and speciation of this faction revealed that only inorganic and simple methylated species were extracted.
authors.affiliation: Ecochemistry Laboratory, Institute of Applied Ecology, Division of Health, Design and Science, University of Canberra, Canberra, ACT 2601, Australia. foster@aerg.canberra.edu.au
authors.forename: Simon
authors.initials: S
authors.lastname: Foster
authors.forename: William
authors.initials: W
authors.lastname: Maher
authors.forename: Frank
authors.initials: F
authors.lastname: Krikowa
authors.forename: Simon
authors.initials: S
authors.lastname: Apte