Used primarily as a reagent to detect and identify carbonyl compounds, such as aldehydes and ketones, in organic chemistry. It reacts with these compounds to form brightly colored precipitates, known as 2,4-dinitrophenylhydrazones, which are useful for qualitative analysis. It is also employed in analytical chemistry for the spectrophotometric determination of carbonyl groups in various samples. Additionally, it serves as a derivatizing agent in chromatography to improve the detection and separation of carbonyl-containing compounds. Its applications extend to biochemical research for studying enzyme activities and metabolic pathways involving carbonyl intermediates.