An automatic flow assembly for on-line dynamic fractionation of trace level concentrations of mercury in environmental solids with high organic load

Abstract

A hybrid and compact flow system for automatic assessment of trace level concentrations of bioaccessible mercury in different phases of environmental solid samples with high organic load is described for the first time. It integrates dynamic sequential extraction with on-line digestion of the extracts and atomic fluorescence spectrometric detection of their total bioaccessible mercury concentration. Four extractants (i.e. deionized water, HNO3 solution, KOH solution and solution containing both Na2S and KOH) are applied sequentially to a solid sample packed in a column to release four bioaccessible Hg fractions (i.e. water soluble, exchangeable, organic matter associated, and sulphide bound ..