One embodiment of the present invention provides an apparatus for analyzing substances within a liquid. The apparatus includes an absorber that comprises one or more layers of absorbent material for absorbing the liquid and one or more sensors embedded within the one or more layers of absorbent material. The sensors are configured to provide information associated with the substances included in the absorbed liquid. The apparatus further includes electrical conductive traces coupled to the one or more sensors, thereby facilitating transmission of outputs of the sensors.
