Influence of sample mass on the measurement confidence of microbial cell wall materials in vacuum-collected floor dust
Published: August 5th, 2012
Revised: July 21st, 2014
Abstract
Technological advancements have increased the analytical sensitivity of a wide range of assays, permitting the analysis of vanishingly small concentrations of analyte. Thus, the minimum quantity of sample needed for analysis has become increasingly driven by the analytical sensitivity of the method. Little consideration has been given to the sample size as a determinant of the representativeness of the greater condition sampled. Here we investigate the influence of sample size on the analysis of endotoxin and glucan in house dust. Based on 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 reasonable sampling precision (~20% RSE).
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Development and validation of the TefTex electrostatic wipe for indoor dust sampling
Published: August 5th, 2012
Revised: July 21st, 2014
Abstract
The aim of this study was to develop and validate a cost-effective method for the collection of indoor dust samples for characterization of endotoxin and ß-(1,3)-D-glucan using TefTex electrostatic wipes – pyrogen-free, polytetrafluoroethylene fibre sampling cloths. Trained research technicians visited 39 homes in Vancouver, Canada in 2009–2010 and collected two wipe samples from door tops and door frames in a bedroom and livingroom.Vacuum-collected dust samples were also obtained from flooring. Glucan and endotoxin were measured by LAL, using previously described methods. The combined endotoxin levels found on the 2 wipes were correlated with endotoxin content of vacuum collected dust (r = 0.262, p = 0.021). Similarly, combined glucan results for the wipes were correlated well with vacuum collected dust samples (r = 0.326, p = 0.004). These results suggest that TefTex wipes may provide a meaningful point-in-time means of ranking endotoxin and glucan content of dust in the home environment.
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