typical chromatograms that were obtained after the analysis of a 5 g L−1 Hg-mixture standard solution
with the two mobile phases (2.0 mM Cys or TU at pH 2.0). Under the optimized conditions, a series of standard solutions containing 0.1, 0.5, 5.0, 20 and 100 g L−1 of each mercury species were analyzed (10 times for 5 g L−1 Hg-mixture standard solution and 3 times for the other standard solutions) with 2.0 mM Cys (pH 2.0) as the mobile phase