Wei Hong Wang (PhD Student)
University of South Australia

Project Title
Selenium Speciation in Se-enriched samples

Biography
Wei Hong's field is analytical chemistry. She finished her bachelor degree in industrial analysis at Chengdu University of Technology (1989) and graduated with a Masters Degree in Sichuan University in China (1992), studied on atomic spectrum analysis. After that she worked in Chengdu research and design institute of chemical industry for seven years, experiencing advanced instrumentation such as AAS, ICP-AES, GC, IC, UV-vis and classical wet chemistry techniques, conducting analysis samples in laboratory reagents, phosphate rock, mineral, ores, rocks, soils and water for chemical quality control issues

Start Date
March 2005

Project Details
Selenium has an important role to play in metabolic processes as an anti-oxidant with important enzymatic interactions. It is also found in various protein structures. The balance between inorganic Se (IV and VI) and organic species (Se (II)) and the quantities of each need definition as the health benefits of the element are defined within quite narrow limits.

In determining Se species in various matrices using ICP-AES, the sensitivity and selectivity of hydride method where Se(II) hydride vapour is carried by argon to the ICP plasma are used. Redox steps are necessary to reduce Se (VI) or to oxidise organoselenium species to Se (IV), prior to hydride formation. Pre-reduction can be conducted off-line by heating the sample for some hours at 70° C with HCl. The fast on-line pre-reduction of Se(VI) to Se(IV) as a new approach was investigated, which thiourea was found the most efficient under the selected conditions and had a further advantage in eliminating interference from various metal species.

The future work will be investigated organic species (Selenomethionine, Selenocystine, Selenomethylcysteine), focus on separation and determination by ESI-ICP-MS in Se-enriched wheat flour and supplements.