Modular Concept for Fluid Handling Systems. A demonstrator Micro Analysis System - Micro Electro Mechanical Systems, 1996, MEMS '96, Proceedings. 'An Investigation of Micro Structur

A modular planar concept for fluid handling microsystems is presented. The concept is based on a planar Mixed Circuit Board with electrical and fluidic interconne:ctions acting as a substrate for sensor and actuator modules. Several modules realised within this concept are presented, and the design as well as modelling and simulation of the fluidic components and systems is discussed. Furthermore, the geineral application of this concept in micro analysis systems is considered. Finally, the modular concept is demonstrated by a micro chemical analysis system containing micro-pumps, flow sensors, an optical absorption cell and control electronics. INTRODUCTION Over the past few years there has been an increasing interest in the development and realisation of miniaturised total analysis systems (pTAS) [ 1-31. This growth is partly due to the rapid developments in fluid handling devices such as micropumps, -valves, -filters and -mixers [4], but is also explained by thLe need for complex (bio)chemical sensor systems with integrated self-test and calibration features. This has led to attempts to fabricate miniaturised flow systems [2,3] and microfabricated parts for separation systems 15-71. However, since such systems typically would comprise a variety of components, materials and technologies, considerable attention should be paid to tlhe iintegrationconcept of such systems. The two extreme forms of integration are hybrid and monolithic. An example of a completely hybrid analysis systems is, the stacked phosphate analyser by Van der Schoot et a1 [2], whereas the liquid dosing system of Lammerink et al. [8] is an example of a monolithic system. In practice, most systems will consist of a combination of these two forms. The concept we propose here enables a rnodular mixed integration of different system components or subsystems on a planar backplane: the Mixed Circuit Board. This MCB serves at the time as mechanical support for the system components (modules), it has the necessary electrical connections (Printed Circuit Board) and contains the microchannels for fluid transport connecting the different modules (Chiannel Circuit Board). Flow Injection Analysis (HA) is a commonly used method for the quantitative determination of a variety of chemical compounds [SI. In several publications the potential advantages of miniaturisation have been indicated [ 10,111. Thus, FIA is an attractive method to be incorporated in a demonstrator system. In this study a very simple chemical system, acidification of the pHindicator Congo-red, is taken as an example to demonstrate the performance of the system concept. MCB CONCEPT Figure 1 shows schematic diagrams of the Mixed Circuit Board which generally consists of two parts to form the fluid channels. The MCB could be built by a glassFlow sensor module Glass