In accordance with one embodiment of the present disclosure a method for detecting urine is described. The method includes contacting urine with a substrate. The substrate includes charged cellulosic fibers having a color- changing composition immobilized thereon, the color-changing composition including a pH indicator, pH adjuster, and a wettability agent, wherein the pH indicator is configured to change color when contacted with urine. The presence of urine is determined based on a change in color of the pH indicator.
