Integration of a Hydrosol Concentrator with an Aerosol to Hydrosol Sampler for Fluid Reuse and Improved Concentration Factors

DAVID ALBURTY (1), Pamela Murowchick (1), Zachary Packingham (2), Andrew Page (2), Tyler Davis (2), Darren Wheeldon II (1).

(1) AlburtyLab, Inc., Drexel, Missouri, (2) InnovaPrep LLC, Drexel, Missouri

     Abstract Number: 446
     Last modified: May 12, 2010

Abstract
Collection and concentration of bioaerosols into a liquid by aerosol to hydrosol samplers is well-established. The final sample volumes delivered by such systems are typically in the range of 1.5 to 15 milliliters. However many state-of-the art biological identification methods, such as PCR, immunoassay, and electrochemiluminescence, typically process much smaller sample volumes, on the order of 5 to 150 microliters.

In this work, an automated aerosol to hydrosol sampler was coupled with an automated hydrosol concentrator for volume reduction of the final sample for delivery to an identifier. The aerosol to hydrosol collector operated at 450 LPM and dispensed 8 milliliter samples to the hollow-fiber membrane filter-based hydrosol concentrator every five minutes. The initial samples were concentrated into 80 microliter final volume samples within two minutes resulting in a 92X average concentration factor. The overall concentration factor of the combined systems was on average 3.5 x 106 (cfu/L liquid)/(cfu/L air)in each five minute sample with a combined efficiency of 70% for 1-micron fluorescent polystyrene microspheres.

Losses in the system were primarily driven by the collection efficiency of the aerosol to hydrosol sampler, which was between 60 and 70%. The efficiency of the concentration step was over 92%. Integration of the systems resulted in an opportunity to recycle some of the collection fluid back into the collection cycle. During three sets of 20 samples (100 min total sampling time per sample set), up to 2/3 of the initial input collection fluid volume used by the aerosol sampler was recovered from the permeate side of the concentrator, where it had been sterile-filtered using a hollow-fiber membrane filter with 100 kD pore size. The buildup of buffer in the collection fluid is described and may be a limiting factor if fluid recycling is implemented in an integrated bioaerosol sampling and concentration system.