Mercury Analysis in Environmental Samples by Cold Vapor Techniques
Environment: Water and Waste
Published Online: 15 SEP 2006
Copyright © 2000 John Wiley & Sons, Ltd. All rights reserved.
Encyclopedia of Analytical Chemistry
How to Cite
Anderson, K. A. 2006. Mercury Analysis in Environmental Samples by Cold Vapor Techniques. Encyclopedia of Analytical Chemistry. .
- Published Online: 15 SEP 2006
The accurate, precise, and automated determination of mercury in biological and environmental samples is complex, not only because of the various oxidation states of mercury (i.e. 0, I and II), but also because of biotic and abiotic methylation and the volatility of several forms of mercury(I and II). Mercury is unique among the metals because of its large vapor pressure at ambient conditions. Mercuric ions in solution can be reduced by tin(II), or sodium borohydride to produce volatile elemental mercury, referred to as the cold vapor process. The mercury is swept out of solution with a carrier gas (in the gas of sodium borohydride, the byproduct is hydrogen) into the cell (or torch) where the atomic absorption (or fluorescence, or emission) is measured. The cold vapor technique removes the mercury from the sample matrix, concentrates the mercury in the analytical sample into a small plug of carrier gas, and provides for a relatively long residence time. Detection limits vary depending on the instrument but are in the submicrogram to nanogram per liter range for atomic absorption spectrometry (AAS), atomic fluorescence spectrometry (AFS), and inductively coupled plasma atomic emission spectrometry (ICPAES).