Nanoliter segment formation in micro fluid devices for chemical and biological micro serial flow processes in dependence on flow rate and viscosity

Micro segmentation of liquids inside micro channels and micro tubes opens an easy way for highly parallelized chemical, biochemical and microbiological processes. The production of liquid segments can be done as a fast serial process and leads to a linear arrangement of samples, which are always individually characterized by their position. The segment formation is a function of injector geometry, interface forces, viscosity of the carrier liquid and flow rate. The formation of droplets inside channels of about 500 mu m diameter was investigated. Therefore, a micro module made by polymethyl-methacryl ate (PMMA) was used for segmentation and integrated in a modular micro fluid arrangement. Microscopic imaging controlled fluidic processes. The inert aliphatic liquid tetradecane and a mineral oil were used as embedding liquids. Segmentation occurred in aqueous solutions of the cationic triphenylmethane dye Malachite Green. The influence of the flow rate on the segment volumes was found to be strongly dependent on the viscosity of the embedding liquid. Operations with series of segments in serial processes as well as possible applications are discussed. (c) 2004 Elsevier B.V. All rights reserved.