Patent ID: 7368289

Claim:
An apparatus for measuring mercury concentration in a flue gas, the apparatus comprising a gas sample acquisition probe, an inertial filter, and an analyzer, wherein: the gas sample acquisition probe is configured to initiate transport of a gas sample from the flue gas to the inertial filter; the inertial filter comprises a porous filter element that removes particulate material from the gas sample and outputs a filtered gas sample; the analyzer measures the amount of gaseous mercury present in the filtered gas sample; the inertial filter comprises metal surfaces that are coated with a protective coating that reduces chemical reactivity of the metal surfaces to gaseous mercury; the protective coating comprises fused silica or a derivative thereof and the coated metal surfaces are further coated with a secondary chemical deactivation layer configured to cover silanol groups on the surface of the protective coating; and the coated filter surfaces are positioned to contact a gas sample flowing through the filter.