Inventors at Georgia Tech and Emory University have engineered a new class of highly effective and easily accessible probes for the detection of intracellular reactive oxygen species. These reduced compounds have been shown to detect superoxide or hydroxyl radicals in nanomolar concentrations. This technology also can possibly detect ROS with high sensitivity in cell culture. Reduced dyes including, but not limited to, hydrocyanines, deuterocyanines, and/or other hydro- or deuterated dyes, such as deuterated leuco dyes, capable of detecting one or more reactive oxygen species, are described herein. The reduced dyes are generally prepared by reducing the oxidized dye with a reducing agent, such as sodium borohydride or sodium borodeuteride. For example, hydrocyanines and deuterohydroethydium (D-DHE or DDE) can be synthesized from cyanine dyes via a one-step reduction using a reducing agent, such as sodium borohydride (NaBH4) or sodium borodeuteride (NaBD4).