Improving the analytical figures of merit of SERS for the analysis of model environmental pollutants

The presence of naphthalene, phenol and benzoic acid derivatives in natural waters constitutes a public health issue. The toxicity and chemical activity of these chemicals and their persistence in the environment depend on the types of functional groups attached to their basic aromatic structure. Surface-enhanced Raman scattering (SERS) spectroscopy has shown promise for the analysis of aromatic compounds owing to a tremendous enhancement of the analytical response and also a large amount of available structural information. Despite these advantages, SERS has not been established as a routine analytical tool owing to limitations in the analytical figures of merit such as reproducibility and linear dynamic range. This paper reports the use of silver-polydimethylsiloxane nanocomposites in combination with a sample translation technique for the improved qualitative and quantitative analysis of model environmental pollutants in water. This novel approach considerably improves the reproducibility and the sensitivity of the technique by minimizing the thermal and photolytic effects inherent in SERS. The results show a linear dynamic range of at least two orders of magnitude with detection limits as low as 2.9 x 10-(8) (M) and a precision of <10% relative standard deviation. The influences of different experimental variables such as irradiation time, translation rate and pH and the potential use of the technique for the analysis of environmental pollutants are presented. Copyright (C) 2004 John Wiley Sons, Ltd.