The Xact Continuous based Mercury Monitor (Xact 645) uses X-ray fluorescence (XRF) to accurately measure mercury from stack gas emissions and has the same features as the Xact 640 . These features include: automatic daily upscale, blank and flow checks; MS Excel- and DAS-compatible data reports; and automatic alarming, QA, and control features. Results are reported micrograms per dry standard cubic meter (µg/dscm).

The Xact 645 offers a number of advantages over other mercury monitoring methods.

• Measures total Hg: elemental, ionic and particulate.

• Does not require stack gas pre-treatment.

• Non-destructive analysis allowing for archiving of samples and re-analysis at a later date.

• Fresh filter with each new sample – no memory.

• Applicable to speciated Hg sampling.

• Does not require gas-phase calibration

• Additional advantages of the Xact 645 based on XRF are:

  • XRF results are independently verifiable.

  • XRF is applicable to particulate fraction.

  • XRF has a smoothly varying, predictable sensitivity.