Spray production and its miniaturization are common need and goal in Chemical Engineering and Chemical fields. This work aims the production of miniaturized low cost spray injection systems using planar and three-dimensional microchannels, both 73 cm long and 100 μm diameter, and acrylic as substrate. Tests and simulation used fluid flow rates up to 10 standard mL/min, for gaseous samples, and up to 1 mL/min to liquid ones; tracers and filming were used to understanding fluid behavior. Simulations and experimental results showed good agreement: planar channels seem to be useful for mixing two liquids whereas three-dimensional channels produce small droplets useful for sample pretreatment in miniaturized impactors.