Gas Digital Microfluidic Platform: Application to Highly Volatile Compound Preconcentration

Digital microfluidics platforms (DMFPs) have shown their efficiency in sample handling, using elementary operations that may be combined to perform complex applications. In this article, we present a new platform for gaseous samples handling involving a two-step digital preconcentration using the miniaturized preconcentrators of the DMFP. Choosing n-pentane at very low concentrations as a model for highly volatile compounds, poorly retained on the sorbent, the DMFP allowed bypassing the limit set by the breakthrough volume by repeating an elementary operation. It enabled a 5-fold increase of preconcentration factors in comparison to a single preconcentration step and an easier monitoring of the model compound. Promising applications are expected, as this system could be adapted to most volatile compound analysis devices, including micro gas chromatographs, to replace the current single-step preconcentration systems. By switching to two-step preconcentration with a DMFP, i.e., a digital preconcentration, it would be possible to get more concentrated samples through the column for easier trace analysis.