Screening of a highly effective fluorescent derivatization reagent for carbonyl compounds and its application in HPLC with fluorescence detection

Carbonyl compounds are widely distributed in organisms, and the commonly used methods for determination of them like UV/fluorescence/mass spectrometry always require derivatization reagents. However, the reported derivatization reagents have significant difference in reactivity, which is very unfavorable for developing highly reactive reagent. In this study, we theoretically investigated the factors affecting the reactivity of hydrazine-based derivatization reagents, and proposed a strategy for filtering highly reactive reagents by quantum chemical calculation . With this strategy, N-propyl-4-hydrazino-1,8-naphthalimide (NPHNA) was filtered out as a fluorescent derivatization reagent. Taking aliphatic aldehydes as representatives, we evaluated the reactivity of NPHNA for carbonyl compounds. The derivatization of NPHNA with aliphatic aldehydes could be finished at room temperature within 60 min or 35 °C within 35 min, which showed higher reactivity than the most popular UV/MS reagent, 2,4-dinitrophenylhydrazine (DNPH). We believe that the strategy we proposed in this work is of great potential to design highly reactive UV/fluorescent/MS labeling reagents for carbonyl compounds and even other analytes.