Characterizing dynamic atmosphere generation system performance for analytical method development

A significant portion of the work of developing and validating methods for volatile organic compound (VOC) sampling in workplace atmospheres involves the use of laboratory-generated atmospheres. The sample variability was evaluated from the dynamic atmosphere generation system used for VOC atmosphere generation and sampling. Characterization of the bias and variability of samples was done for a variety of atmospheres containing neat n-heptane and mixtures of VOCs sampled on activated coconut shell charcoal. Estimates of sampling variability ranged from 2% for neat n-heptane to 12% for a component in the 10 VOC mix. Sample variability increased for lower concentration samples and for mixtures of VOCs compared to single component atmospheres. This study can serve as a baseline for future atmosphere sampling experiments evaluating performance at lower concentrations and mixed VOC environments.