Photochemical vapor generation and in situ preconcentration for determination of mercury by graphite furnace atomic absorption spectrometry

A new and sensitive method is described for the on-line preconcentration and determination of ultra-trace mercury by coupling a trapping scheme based on coating gold nanorods onto the inner wall of the graphite furnace for mercury vapor from photochemical vapor generation (photo-CVG) and graphite furnace atomic absorption spectrometric (GF-AAS) detection. The optimal experimental conditions for the photo-CVG, trapping and atomization were carefully investigated, together with the interference from transition metals. The limit of detection of this method was found to be 0.02 mu g L-1 and the precision was better than 5% at 0.1 mu g L-1. Mercury in four spiked water samples and two certified reference materials was successfully determined by the proposed method.