Influence of sample mass on the measurement confidence of microbial cell wall materials in vacuum-collected floor dust

Technological advancements have increased the analytical sensitivity of a wide range of assays, permitting the analysis of vanishingly small concentrations of analyte. Accordingly, the minimum quantity of sample needed for analysis has become increasingly driven by the ever greater analytical sensitivity of laboratory methods with little consideration of the influence of decreasing sample mass on the representativeness of the sampled environment. Here we investigate the influence of sample mass on the measurement of endotoxin and glucan in house dust. Using a combination of empirical sampling and modeling, we demonstrate that a minimum of 150 mg of dust is needed for analysis in order to achieve a measurement precision of 20% relative standard error (RSE).