Review: Using 2,4-dinitrophenylhydrazine in spectrophotometric determination

Abstract

2,4-Dinitrophenylhydrazine (2,4-Dnphh) is substituted hydrazine. It is structure contains hydrazine which is the main active functional group. 2,4-Dnphh is an important reagent in analytical chemistry it is used firstly in the identification (qualitative analysis) of carbonyl groups (aldehyde and ketones compounds). 2,4-Dnphh is react with aliphatic and aromatic carbonyl compounds to produce the corresponding 2,4- dinitrophenyl-hydrazone. The aromatic carbonyls give red precipitates compared with aliphatic carbonyls giving more yellow color. The two colored products were achieved according to the addition-elimination reaction, the reaction included nucleophilic addition of amino group (-NH2) to the carbonyl group(C=O), then the elimination of the H₂O molecule. Also, a modification of 2,4-Dnphh to produce a derivative can be used as a chemical sensor for some colorimetric detection of various compounds. Recently 2,4-Dnphh is used in quantitative spectrophotometric estimation of various compounds via oxidative coupling reaction and diazotization-coupling reaction, and also 2,4- dinitrophenylhydrazone-compound prepared from the reaction of 2,4-Dnphh with compound to be determined give good results in injection to the column of high-performance liquid chromatography. The present review included all methods as possible in the literature including the uses of 2,4-Dnphh in the qualitative and quantitative determination of various compounds.