Optimisation of sample treatment for arsenic speciation in alga samples by focussed sonication and ultrafiltration

Garcia Salgado, Sara and Quijano Nieto, M. Angeles and Bonilla Simon, M. Milagros (2006). Optimisation of sample treatment for arsenic speciation in alga samples by focussed sonication and ultrafiltration. "Talanta", v. 68 (n. 5); pp. 1522-1527. ISSN 0039-9140. https://doi.org/10.1016/j.talanta.2005.08.004.

Description

Title: Optimisation of sample treatment for arsenic speciation in alga samples by focussed sonication and ultrafiltration
Author/s:
  • Garcia Salgado, Sara
  • Quijano Nieto, M. Angeles
  • Bonilla Simon, M. Milagros
Item Type: Article
Título de Revista/Publicación: Talanta
Date: February 2006
ISSN: 0039-9140
Volume: 68
Subjects:
Freetext Keywords: Arsenic speciation; Extraction by focussed sonication; Ultrafiltration; Algae; HPLC–ICP-AES
Faculty: E.U.I.T. Obras Públicas (UPM)
Department: Ingeniería Civil: Hidráulica y Energética [hasta 2014]
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

A procedure for arsenic species fractionation in alga samples (Sargassum fulvellum, Chlorella vulgaris, Hizikia fusiformis and Laminaria digitata) by extraction is described. Several parameters were tested in order to evaluate the extraction efficiency of the process: extraction medium, nature and concentration (tris(hydroxymethyl)aminomethane, phosphoric acid, deionised water and water/methanol mixtures), extraction time and physical treatment (magnetic stirring, ultrasonic bath and ultrasonic focussed probe). The extraction yield of arsenic under the different conditions was evaluated by determining the total arsenic content in the extracts by ICP-AES. Arsenic compounds were extracted in 5 mL of water by focussed sonication for 30 s and subsequent centrifugation at 14,000 × g for 10 min. The process was repeated three times. Extraction studies show that soluble arsenic compounds account for about 65% of total arsenic. An ultrafiltration process was used as a clean-up method for chromatographic analysis, and also allowed us to determine the extracted arsenic fraction with a molecular weight lower than 10 kDa, which accounts for about 100% for all samples analysed. Speciation studies were carried out by HPLC–ICP-AES. Arsenic species were separated on a Hamilton PRP-X100 column with 17 mM phosphate buffer at pH 5.5 and 1.0 mL min−1 flow rate. The chromatographic method allowed us to separate the species As(III), As(V), MMA and DMA in less than 13 min, with detection limits of about 20 ng of arsenic per species, for a sample injection volume of 100 μL. The chromatographic analysis allowed us to identify As(V) in Hizikia (46 ± 2 μg g−1), Sargassum (38 ± 2 μg g−1) and Chlorella (9 ± 1 μg g−1) samples. The species DMA was also found in Chlorella alga (13 ± 1 μg g−1). However, in Laminaria alga only an unknown arsenic species was detected, which eluted in the dead volume

More information

Item ID: 9628
DC Identifier: http://oa.upm.es/9628/
OAI Identifier: oai:oa.upm.es:9628
DOI: 10.1016/j.talanta.2005.08.004
Official URL: http://www.sciencedirect.com/science/journal/00399140
Deposited by: Memoria Investigacion
Deposited on: 11 Nov 2011 10:12
Last Modified: 20 Apr 2016 17:58
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