Systems, devices, kits, and methods for detecting and quantifying targeted compounds within a liquid (such as urine) are provided. Such systems, devices, and methods may be autonomous, noninvasive, and provide quick and accurate results. The systems and devices are at least partially disposable (single-use) and configured to be embedded within or applied to a conventional diaper or the like. Methods for using the systems and devices hereof include receiving a liquid to be tested within a portion of a disposable device, allowing the liquid to traverse through one or more channels defined within the device in a controlled fashion, reacting the liquid with one or more chemical reagents, using a sensing unit to collect photocurrent data regarding the chemical reach on(s), and wirelessly transmitting that data to a computing unit for storage and quantitative analysis.
