Towards Surface-Enhanced Raman Scattering using electroless substrate for trace arsenic detection and speciation

Description

Arsenic is one of the most toxic elements present in the environment, especially in water. The World Health Organization (WHO) recommends a maximum concentration of arsenic in drinkable water of 10 µg/L (10 ppb). Sensors implementing Surface Enhanced Raman Scattering (SERS) can detect chemical species at low concentrations. The aim of this study is to compare two kinds of silver-coated SERS substrates for detection and speciation of trace, trivalent and pentavalent, inorganic arsenic compounds. One type of substrates were prepared by a classical thermal evaporation technique, the second type by an electroless process. The electroless substrates allow to differentiate As(3) and As(5) with a limit of detection (LOD) 1 µg/L (1 ppb) equal for each valency, below WHO recommendation. Though the SERS intensity shows a non linear behaviour over a large analyte concentration range of five orders of magnitude, these preliminary results are discussed the framework of the demonstration of a trace As SERS sensor in drinkable water.

Additional details