Abstract
An automated continuous monitoring system for total mercury at sub-ppb level based on cold-vapor atomic absorption spectrometry-"continuous micro flow analysis" is described. The method uses continuous flow sample digestion, reduction and extraction in small bore tubes (0.25mm i.d.) at very slow flow rates of reagents (17-23μl min-1). On descrete injection of sample (180μl), analytical time for the determination of total mercury was about 4min per one sample. The detection limit of mercury(II) was about 0.15μg l-1 (S/N=3) using a gas flow cell with 40mm lightpass length; the relative standard deviation for the measurement at 2μg l-1 level was 1.2% (n=5). On continuous micro flow injection of sample at a flow rate of 180μl min-1, the system was successfully applied to the completely continuous monitoring of total mercury in wastewater.
