Sensor arrays, methods, and systems for detecting the presence of gas phase materials by the formation of films based on the gas phase material are disclosed. The magnetic microwire is a glass-coated amorphous magnetic microwire characterized by a large Barkhausen discontinuity and substantially zero or positive magnetostriction. The second fluid is preferably in a different state from the first fluidliquid-gas or gas-liquid combinations. The patterned CNT array can also be patterned by using a patterned mask on the substrate to form the CNT array by growing. In one embodiment, the invention is employed for expressing page flows associated with the checkout phase of an online store web application.