Flexible fabrication, packaging, and detection approach for microscale chromatography systems

This paper describes a simple manufacturing and packaging method to fabricate microfluidic channels and obtain an optical detection interface for rapid prototyping of microscale chemical and biological analysis systems. Specifically, this work reports on efforts to develop new methods for simple, fast and reliable design and fabrication of microscale field flow fractionation (FFF) based biological analysis systems and a compatible optical detector flow cell. First, a rapid prototyping technique is used to realize electrical FFF microchannels and second, a modular detector interface with a 38 nl detection region is employed, which when connected to an appropriate microfluidic channel, results in a ElFFF prototype. Detector characterization is carried out to evaluate important figures of merit such as sensitivity, S/N ratio and limit of detection. Plate height, a primary performance metric for field flow fractionation is determined and compared with an on-chip detector. Separation of a multicomponent mixture of polystyrene particles is also demonstrated. The developed system allows for an easy plug-and-play approach to the optical interface and has resulted in improved operational flexibility and robustness of the microsystem.