Silagerm 8040-Based Planar Microfluidic Chips for Sampling and Sample Preparation in the Analysis of Gas Media

A technology is developed for manufacturing planar microfluidic chips (MFCs) based on Silgard 8040, encompassing template fabrication, mold production, sealing, and adsorbent filling. These MFCs, filled with a Porapak-Q adsorbent, facilitate sample preparation and calibration under uniform conditions, integrating both sample collection and preconcentration stages. Experimental investigations have identified optimal conditions for acetone preconcentration using Silgard 8040-based MFCs, achieving a maximum concentration factor of 43 at adsorption temperature (T_ads) of 0°C, desorption temperature (T_des) of 70°C, adsorption volume (V_ads) of 45 mL, and desorption time (t_des) of 1 s. The feasibility of using MFCs for sample collection and preparation, taking into account sample storage time, has been evaluated. The procedure maintains accuracy within 6–10% over 8 h without a necessity for additional drying of the collected samples from exhaled air.