With over 1300 commercial testing labs in the United States, one out of every three samples is for water analysis. There has
been an even stronger emphasis on mercury testing and its concentration in our water supplies. This application note describes
the use of cold vapor atomic absorption spectroscopy as described in the EPA method 245.1 to determine mercury concentration
in water samples including drinking, surface, ground, sea, brackish waters, and industrial and domestic waste waters.
Determine mercury concentrations in surface water samples. In addition to the water samples, pre and post QC checks (15 ppt
standards) served to ensure instrument stability and accurate results.
Principle of Operation
Milestone's Mercurio AAMA-80 incorporates the following sequence to perform a direct measurement in a liquid sample: Aliquot
of sample transferred automatically to reaction mixing block through a peristaltic pump where it is mixed with argon gas and
a stannous chloride reagent solution, mercury vapors pass through a gas-liquid separator and purification system followed
by Hg amalgamation and detection. Following amalgamation, the mercury vapors are released to a single beam, fixed wavelength
atomic absorption spectrophotometer. Absorbance is measured at 253.7 nm as a function of mercury content. The system is concurrently
cleaned with the amalgamation step for a seamless and more productive process.
Figure 1: Milestone’s Mercurio AAMA-80.
See Table I.
Table I: QC Hg standards and surface water samples
Discussion and Conclusion
The Mercurio AAMA-80 successfully recovered 100% of the 15 ppt Hg standards and processed 10 surface water samples with excellent
reproducibility and accuracy without any interference.
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