Highly sensitive method for aldehydes detection: Application to furfurals analysis in raisin and bovine milk powder

A pre-column fluorescent derivatization method based on nitrone formation has been applied to determine furfurals (e.g. furfural (F), 5-methyfurfural (5-MF) and 5-hydroxymethylfurfural (5-HMF)) in food samples for the first time. An N-substituted hydroxylamine reagent 4-((hydroxyamino)butyl)-7-hydroxycoumarin (HAHC) was used to react with the aldehyde group of furfurals to form stable nitrone derivatives with high fluorescence intensities . The reactions proceeded under mild conditions in 30 min with high derivatization yields (>93%). A baseline-separation of three furfurals derivatives was subsequently achieved within 25 min on a reversed-phase column. The detection limits were at the low femtomol level (S/N = 3, 20 μL per injection). The linear range of the calibration curve was 0.4–4000 nM with good correlation coefficients (R 2  ≥ 0.9991). The proposed method was further applied for food sample analysis, such as bovine milk powder and raisin. Satisfactory recoveries were obtained in the range of 94.7%–103.5%. Above all, this pre-column derivatization method is simple, fast and highly sensitive, providing an effective and promising way for future studies of aldehydes in different matrices.