Analysis mercury

Atomic absorption spectroscopy is more suited to samples where the number of metals is small, because it is essentially a single-element technique. The conventional air—acetylene flame is used for most metals however, elements that form refractory compounds, eg, Al, Si, V, etc, require the hotter nitrous oxide—acetylene flame. The use of a graphite furnace provides detection limits much lower than either of the flames. A cold-vapor-generation technique combined with atomic absorption is considered the most suitable method for mercury analysis (34). 

Samples for mercury analysis should preferably be taken in pre-cleaned flasks. If, as required for the other ecotoxic heavy metals, polyethylene flasks are commonly used for sampling, then an aliquot of the collected water sample for the mercury determination has to be transferred as soon as possible into glass bottles, because mercury losses with time are to be expected in polyethylene bottles. 

Third, continued periodic monitoring of fishery and wildlife resources is important, especially in areas with potential for reservoir development, in light of the hypothesis that increased flooding increases the availability of mercury to biota. The use of museum collections for mercury analysis is strongly recommended for monitoring purposes. For example, the Environmental Specimen Bank at the Swedish Museum of Natural History constitutes a base for ecotoxicological research and for spatial and trend monitoring of mercury and other contaminants in Swedish fauna (Odsjo et al. 1997). 

Cold vapor mercury Light absorbed by atoms of mercury generated by chemical reaction at room temperature is measured An excellent technique for mercury analysis... 

CASE STUDY IID MERCURY ANALYSIS IN A NATURAL GAS PLANT... 

The instrumentation adds this device on-hne with the standard units for mercury analysis and is also controlled by the software. Steps have been taken to minimize the blank levels of mercury in the solutions, gases and reagents. 

The methods for mercury analysis described earlier are based on continuous-flow technology and although this is easy to translate these procedures into an on-hne regine, several problems are associated with this. These are (a) presentation of a representative sample (b) conversion of all forms of mercury in the sample into the divalent form prior to reduction to mercury and (c) engineering the system to include sufficient robustness, control and flexibility. 

Common procedures of qualitative mercury analysis, i.e. using aluminum foil hooked up to a battery to determine the presence of mercury in a solution (mercury metal forms on the surface of the aluminum foil), suggested the use of aluminum as a cathode. This principle was applied on a larger scale using aluminum wire which had to be flattened to a certain thickness for the voltage used. 

Box 21-1 Mercury Analysis by Cold Vapor Atomic Fluorescence... 

Mercury analysis by U.S. Environmental Protection Agency Method 1631... 

New boxed applications include an arsenic biosensor (Chapter 0). microcantilevers to measure attograms of mass (Chapter 2), molecular wire (Chapter 14), a fluorescence resonance energy transfer biosensor (Chapter 19), cavity ring-down spectroscopy for ulcer diagnosis (Chapter 20), and environmental mercury analysis by atomic fluorescence (Chapter 21). 

Coal and Ash Analysis. The coal and ash samples were separated into 20-40 g representative samples in the laboratory by a small riffle splitter. These samples were then pulverized with a mortar and pestle. The moisture content was determined by weighing the sample, drying it at 103 °C, and then reweighing it. These samples were kept in a desiccator and were subsequently used for the mercury analysis. 

Ferric thiocyanate -as flocculating agent [FLOCCULATING AGENTS] (Vol 11) -in mercury analysis [MERCURY] (Vol 16)... 

---