Precision micro-dispensing based upon ink jet technology has been used in medical diagnostics since the early nineties, and now is moving into a wide range of applications. Ink-jet printing technology can reproducibly dispense microdroplets of fluid with diameters of 15 to 100 µm (2pl to 5nl) at rates of 0 -25,000 per second from a single drop-ondemand printhead. The deposition is non-contact, data-driven and can dispense a wide range of fluids. It is a key enabling technology in the

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... of Bio-MEMS devices, Sensors, Micro-fluidic devices and Micro-optical systems. In this paper, we will discuss the use of this technology for real time calibration and testing of chemical sensors. The technology is based upon test systems developed for olfaction testing which are capable of precisely dispensing chemical aromas in concentration that vary over 6 orders of magnitude. The droplets of each chemical are thermally converted into a vapor that is fed directly into the sensor under test.