Determination Of Trace Amounts Of Mercury By Cold Vapor Generation AAS With On-line Preconcentration By Polyaniline Micro Column

Owing to its advantages of faster analysis, better precision, lower consumption of reagents and readily automated operation, the flow injection (FI) on-line microcolumn preconcentration and separation technique have undergone rapid development since its advent in early eighties. It has an indispensable importance for the determination of trace amount of analyte in complicated samples. However, the adsorbents used for this purpose are mainly commercial ion-exchange resins and other adsorbents such as activated carbon and activated alumina. Hence, the synthesis and selection of suitable adsorbents with special advantages are one of the most important tasks for improving the technique.Polyaniline (PAN) is one of the most intensively studied conducting polymers for the decade due to its excellent combination of properties, such as stability, price, ease of synthesis, treatment, etc. PAN exists in various oxidation states, and shows reversible redox property, can be used for the separation or recollection of noble metals. Here, PAN was investigated for the preconcentration of inorganic mercury. Preliminary experiments with powdered PAN for the quantitative adsorption of mercury had shown that the retention of Hg(II) was almost independent of medium acidity.The flow injection vapor generation atomic spectrometry technique combined with PAN on-line micro column preconcentration system was applied for the determination of trace amounts of mercury in water samples. The flow rate of sample, the volume of sample, the composition and concentration of elute were optimized. With 12mL sample solution , the response range was 0.1 - 4.0μg/L, and the detection limit was 0.013 μg/L (3σ), Precision of 2.3% RSD (n=11) for determination of 3 μg/L Hg. The method was applied to the determination of Hg in five types of water samples. The determination result obtained for a environmental water sample standard reference material was in the good agreement with the certified value, and the recoveries by spiking 2 μg/L Hg in the water samples were in the range of 98.3%-104%.