CEM - Abstract

Abstract Information :

Reliable, sub-ppb trace gas measurements are essential for a range of industrial process and air quality monitoring purposes. Picarro’s Cavity Ring-Down analyzers (CRDS) have become the preferred technology for stable and continuous, high-precision trace gas measurements since the commercial release in 2005. Currently, they are used for a range of gas monitoring purposes, such as: fence line emissions near industrial facilities (HF, H2CO, H2S, EtO), air quality inside sterilized isolator spaces (H2O2), occupational exposure limits to toxic gases, stack emissions monitoring to comply with regulations and emissions (HF, H2CO, H2S, EtO), process control to improve yield (HF, SO2, NH3, H2S, HCl), and many other applications.

A key feature of CRDS analyzers is their unprecedented stability and ease of use. This is thanks to the low calibration requirements, which is accomplished by the patented wavelength monitor. The wavelength monitor tracks one or more well-defined spectral reference lines (most commonly: water), which guarantees the unmatched low drift. Therefore, the performance of Picarro’s industrial trace gas analyzers only needs to be validated on an infrequent basis (e.g., during a yearly performance validation).

Commonly, a calibration of crucial gas measurement equipment is performed with commercially available and certified gas standards, specifically to determine the linearity and the zero value of the analyzer. Importantly, sourcing accurate standards for hazardous, corrosive, and reactive trace gases is challenging and often technically not possible. Here we will present a three-fold approach for calibration (validation) of Picarro’s CRDS analyzers for reactive trace gases: 1. Factory calibration with a golden analyzer, 2. Validation of the linearity of an analyzer using a surrogate gas approach, and 3. Accurate determination of the zero value of an analyzer.