Reactive oxygen species (ROS) including the super oxygen free radical, hydrogen peroxide and its downstream product (peroxide and hydroxide) etc. ROS is involved in cell growth, proliferation, differentiation of development, aging and apoptosis as well as many physiological and disease process. The DCFH-DA (2, 7-dichlorofuorescin diacetate) is the most commonly used and most sensitive intracellular reactive oxygen detection probe. DCFH-DA has no fluorescence, it is hydrolyzed into DCFH (dichlorofluorescin) by ester hydrolysis enzyme after entering cells. DCFH can be oxidized to strong green fluorescence material DCF (dichlorofluorescein) that cannot pass through cell membrane when active oxygen exists. Its fluorescence has the largest wave crest in excitation wavelength of 502nm and emission wavelength of maximum peak around 530nm, the intensity is proportional to the level of reactive oxygen species in cells. This ROS detection system has low background, high sensitivity, good repeatability and simple operation.||Kit Components (see Protocol for final kit quantities):|Reagent 1,|DCFH-DA 10mM in DMSO, 0.1mL||Reagent 2,|ROS hydrogen donor, 1mL||Storage and Stability:|Store powder at 4°C liquid at -20°C. Store other components at 4°C. Stable for at least 6 months For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.