Performance of a Robotic Weighing System and Quality Practices for Gravimetric Mass Measurements
Gravimetric analysis is an essential baseline measurement for air quality monitoring networks to monitor particulate matter and to track adherence to the National Ambient Air Quality Standards. The Clean Air Act requires the state and local agencies to monitor and report particulate matter concentrations as a part of their air monitoring requirements. Highthroughput gravimetry laboratories need to be capable of weighing thousands of filter-based samples each month while maintaining strict quality control requirements set by the Federal Reference Method for the determination of particulate matter in ambient air. Here, we present an evaluation of the performance of a robotic weighing system and review quality control measures applicable to gravimetric mass measurements. Results from this study show robotic weighing is better able to control static effects common to manual weighing. Electrostatic charges are increased with each human movement during the manual weighing process and, as indicated here, can occur suddenly and be difficult to detect. This study provides insights into the ability of robotic weighing to mitigate this effect and suggests new quality practices to detect and track the static effect.