Performance of Two Different Techniques to Concentrate Samples for Bioaerosol Quantification

We evaluated two concentrating techniques that could be used to improve bioaerosol detection and quantification: A BioChromato Smart Evaporator C1 (BioChromato, Inc.) and two Concentrating Pipette (CP) models (CP-150 and CP-Select) (InnovaPrep, LLC). We determined the concentration factor (CF) (the concentration of particles in the final solution compared to the concentration in the initial solution) and the particle losses when processing the samples with polystyrene latex (PSL) beads and different species of bacteria. When processing total particles, regardless of the culturability status, the losses for the Evaporator were 3.70-23.89%; for the CP-models, the losses ranged from 0.20% to 67.22%. For the culturable particles processed with the CP devices, the losses ranged from 42.85% to 90.19% and were higher for Gram-negative pseudomonads compared to Gram-positive B. subtilis. Despite the loss of particles, both devices yielded more concentrated final solutions. The CF for the Evaporator was 3.59-10.92; the CF values for the CP devices ranged from 55.77 to 184.64 for total particles and from 6.29 to 96.52 for culturable bacteria. This higher CF was mainly achieved due to lower final suspension volumes. The study demonstrated that the two concentrators can improve particle detection, but that one should take particle losses into account.