Investigating a Drop-on-Demand Microdispenser for Standardized Sample Preparation

Report No. ARL-RP-0396
Authors: Ellen L. Holthoff, Mikella E. Farrell, and Paul M. Pellegrino
Date/Pages: September 2012; 14 pages
Abstract: The existing assortment of reference sample preparation methods presents a range of variability and reproducibility concerns, making it increasingly difficult to assess chemical detection technologies on a level playing field. We are investigating a dropon-demand table-top printing platform which allows precise liquid sample deposition and is well suited for the preparation of uniform and reproducible reference materials. Current research focuses the development of a sample preparation protocol for explosive materials testing based on drop-on-demand technology. Device settings were determined for optimal droplet formation and velocity. Droplet mass and reproducibility were measured using ultraviolet-visible (UV-Vis) absorption and a sensitive microbalance. The results presented here demonstrate the operational factors that influence droplet dispensing for specific materials (e.g. energetic and interferents). Understanding these parameters allows for the determination of droplet and sample uniformity and reproducibility (typical calibration goodness of fit R2 values of 0.991, relative standard deviation or RSD ≤ 5%), and thus the demonstrated development of a successful and robust methodology for energetic sample preparation.
Distribution: Approved for public release
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Last Update / Reviewed: September 1, 2012