Royal Society of Chemistry, RSC Advances, 29(4), p. 15276
DOI: 10.1039/c4ra01393j
Full text: Download
A simple frit-free PDMS (polydimethylsiloxane) microfluidic chro-matographic device, packed with diatomaceous earth (DE) micro-particles as a normal phase stationary material using iron oxide magnetic nanoparticles is described. The separation of two model dyes was successfully demonstrated by integrating on-chip fibre optic detection to create a lab on a chip type of device. Microuidics offers unprecedented advantages for design of small devices, with complex functions, improved accuracy, simple use, low energy consumption and high throughput. 1 These features, especially portability, low-cost and time effective analysis with ultra-low volume of analytes (mL to nL), make microuidic devices highly attractive candidates in analytical chemistry. Liquid chromatography (LC) is recognized as one of the most powerful separation techniques in analytical chem-istry, due to its proven high separation efficiency, reliability and versatility. There is a strong trend in recent years to integrate LC into microuidics in several ways to develop various chro-matographic devices in micro scale including capillary liquid chromatography (CLC), capillary electro chromatography (CEC), 2 open-tubular columns, 3 polymer or silicon-based monolithic columns, 3,4 microfabricated pillar columns, 5 and packed columns. 6 These new microchip based LC techniques are under continuous development, mainly focusing on improvement of their specic features such as a microchip design, the separation efficacy of stationary phase, ow systems, sensitivity of detection method and specic applications. However there is lack of integrated approaches to combine these improvements into one step to considerably improve the performance of LP microuidic devices. One of the main practical challenges in conventional and microchip based LC is to retain stationary phase of micropar-ticles inside the microchip channels or microcolumns during packing and separation process. Several methods and approaches were developed to solve this problem by using the frit, 7 physical barriers, 6,8 tapered capillary, 2,9 valve systems 10 and