Micro preconcentrator with seedless electroplated gold as self-heating adsorbent

This paper introduces, for the first time, electrodeposited gold as a new adsorbent material for micro preconcentration applications. The thin film gold layer serves as both an adsorbent and a resistive heater thus allowing self-heating capability without the need for additional off or on-chip heaters. The self-heating adsorbent enhances the desorption efficiency, reduces power consumption, and is simple to fabricate. The gold layer is deposited by seedless electroplating on silicon microstructures embedded in the cavity of microfabricated preconcentrators (¿PCs). The presented devices have outer dimensions of 7 mm × 7 mm, total inner surface area of ~10 m², total inner volume of ~6.5 ¿L, and encompass more than 3500 high-aspect-ratio (30 ¿m × 120 ¿m × 240 ¿m) pillars. The ¿PC design provided high surface to volume ratio, high adsorption capacity, and improved sample distribution. The performance of these ¿PCs has been evaluated by using the preconcentration factor of several samples as a performance metric. Preconcentration factors of 810, 6156, 405 has been determined for 1-propanol, methanol and acetone, respectively.