2,2-Di(4-tert-octylphenyl)-1-picrylhydrazyl (DPPH) is classified as a “stable” free radical since it has a long shelf life and can be synthesized and stored under normal laboratory conditions.

2,2-Di(4-tert-octylphenyl)-1-picrylhydrazyl can be used as a calibration standard in electron paramagnetic spectroscopy (EPR) and as a radical scavenger in polymers. It is also used as an efficient reagent in the “DPPH calorimetric assay” to study radical scavenging activities of diverse chemical compounds, mostly of phenolic nature. When DDPF reacts with antioxidant molecules, its color changes from deep purple to pale yellow, which allows the spectrophotometric determination of the antioxidant activity.