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. Microuidics 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 microuidic 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 microuidics 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 specic features such as a microchip design, the separation efficacy of stationary phase, ow systems, sensitivity of detection method and specic applications. However there is lack of integrated approaches to combine these improvements into one step to considerably improve the performance of LP microuidic 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