Abstract: The present technology describes various embodiments of devices for processing, analyzing, detecting, measuring, and separating fluids. The devices can be used to perform these processes on a microfluidic scale, and with control over fluid and reagent transport. In one embodiment, for example, a device for performing chemical processes can include a porous wick comprising a pathway defined by an input end, an output end, and a length between the input end and the output end. The pathway is configured to wick fluid from the input end to the output end by capillary action. The device can further include a reagent placed on the pathway. The reagent can be placed in a pattern configured to control a spatial or temporal distribution of the reagent along the pathway upon wetting of the pathway.