Determination of total mercury in natural gas liquid and condensate by carbon adsorption and slurry sampling ETAAS

Abstract

A method for the determination of total mercury in natural gas liquid (NGL) and condensate (NGC) was delveloped. The trace amount of mercury was concentrated by adsorption on activated carbon powder, which was subsequently filtered and determined using the slurry sampling electrothermal atomic absorption technique. A concentration factor of up to 1000-fold was obtained in the preconcentration step. Triton X-100 at 5000 μg/m L was necessary to disperse the adsorbed carbon powder in order to obtain a homogeneous slurry. Palladium was used as the chemical modifier in the ETAAS determination. Activated carbon could play the same role as ascorbic acid to facilitate palladium to stabilize the mercury and to enhance the sensitivity. The recovery of spiked mercury was found to be better than 90%. The repeatability and detection limit for NGL were found to be 8.4% and 2.0 ng/mL, respectively.