The method describes how to determine the mercury content of water using atomic absorption spectrometry. Compounds containing mercury are generally found in natural waters at very low mass concentrations (0.1 µg/l). However, in certain types of industrial wastewater, higher concentrations may exist.
Mercury exists in water not only in ionic form. Organic mercury compounds are also present in wastewater; moreover, a biochemical transformation occurs in water in which inorganic mercury compounds change into organometallic compounds.
Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
Mercury is reduced by sodium tetrahydroborate to its elemental form by allowing it to flow over a precious metal (e.g., a gold-platinum mesh) with the evolving hydrogen along with the assistance of an inert gas. By rapidly heating the adsorbent, the mercury is released again. It is transferred into a cuvette using a carrier gas where the absorbance is measured.
This method is described as a cold vapor technique.