Quantitative Moisture Measurements for Limited Gas Volumes

Adam Pimentel and Curtis Mowry

Sandia National Laboratories

Water is not an “analyte of interest” in many analytical measurements. In some specific cases, however, moisture is a very important species related to aging and lifetime issues. In gas applications, moisture measurements are typically performed using solid-state Panametrics flow-through sensors. These sensors are designed for flow-through gas samples, and thus liters of gas are needed. Specifications and real-world samples can range from -60°C frost point (~10ppmV) to higher than 10°C frost point (>12,000 ppmV). The volume available is often limited, as in a fixed-volume compatibility test. We have published low sample volume moisture analyses using GC/PDID, gas chromatography with a pulsed-discharge helium ionization detector; and have extended this work to materials compatibility-type samples and other low-volume gas samples. The method covers the desired sensitivity range and uses commercial off-the shelf (COTS) equipment. We are in the process of automating this method for adoption at other sites interested in moisture measurements. This presentation will provide examples of measurements and discussion of calibration logistics, time required, accuracy, lessons learned, and future efforts planned.

Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the U.S. DOE’s NNSA under contract DE-NA0003525.