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P. S. Analytical's involvement with trace
mercury analysis goes back many years, firstly with Hydride/Vapor Generators
linked to proprietary AA or ICP spectrometers, and then with the PSA Merlin
Plus mercury fluorescence detection system. The Merlin Plus quickly became the
UK water industry's standard for the measurement of mercury in water, sewage,
and sludge, etc., offering the advantage of speed, ease of use, a wide linear
dynamic range and detection limits of below 1 part per trillion (1 x 10
¹²).
The development and characterization of a gold
sand mercury trapping system allowed the inherent sensitivity of the Merlin to
be applied to air monitoring. As the sample gas (e.g. air) is pumped over the
gold sand trap any mercury present in the sample amalgamates with the gold. The
sample gas can then be flushed out of the trap with a carrier gas, usually
argon, to prevent any interference or quenching effects. The trapped mercury
can be re-vaporized by rapid heating and flushed into the detector to produce a
response. |
