Sample preparation of chemical warfare agent simulants on a digital microfluidic (DMF) device using magnetic bead-based solid-phase extraction

In the present study, the purification and extraction of five chemical warfare agent (CWA) simulants, dimethyl methyl phosphonate, di(propylene glycol) methyl ether, methyl salicylate, triethyl phosphate, and diethyl phthalate, on a digital microfluidic (DMF) device were demonstrated. The DMF on-chip purification and extraction was performed using a magnetic bead (MB)-based diol solid-phase extraction procedure. The extracted CWA simulants were detected using both matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and gas chromatography-mass spectrometry (GC-MS). The method detection limits of the DMF-MS approach using diol-MBs were also determined. In particular, for the DMF-GC-MS, the quantitative analysis ability was validated by determining accuracy, precision, calibration curve performance, and recovery efficiency. This study clearly shows that the CWA analyses can be automated on the DMF-MS platform, thereby minimizing human involvement.