Effect of reduction agents on determination of mercury by atomic absorption method

In the determination of mercury by atomic absorption method, higher, sensitivity is obtained when mercury present as mercury (I) than mercury (II). Ascorbic acid was found to be the best reducing agent although decrease on absorbance was observed on standing in the presence of ascorbic acid. This decrease on absorbance was confirmed to be due to the vaporization of mercury which was produced either by the reduction of mercury (II) to mercury (0) or disproportionation reaction of mercury (I). The addition of perchloric acid was effective to prevent the vaporization of mercury and to get good reproducibility.