Rapid Determination of Long-chain Aliphatic Aldehyde in Gutter Oil by Fluorescent Derivatization-High Performance Liquid Chromatography / 分析化学

ABSTRACT

Reuse of waste oil in cooking has been the social concern for long time, but until now there is no reliable method to identify the gutter oil.In this work, based on the generation of long-chain aliphatic aldehydes in the refinement of gutter oil, gutter oil and adulterate cooking oil were identified by determining hexanal, heptanal, octanal, nonanal and decanal in oil sample with high perfomance liquid chromatography (HPLC) method using O-(3-(9H-carbazol-9-yl)propyl)hydroxylamine as the fluorescent derivative reagent.At first, 10 μL of oil sample was dissolved in 200 μL of isopropanol, then reacted with O-(3-(9H-carbazol-9-yl)propyl)hydroxylamine to form the stable derivatives, extracted with acetonitrile and injected into HPLC for analysis.The derivatives were separated on a C18 column within 15 min with ACN-H2O (90∶10, V/V) as mobile phase.The fluorescence detector was set at λex/λem=292 nm/348 nm.The linear range of 5 kinds of long-chain aliphatic aldehydes was 0.01-1.00 μmol/L with limit of detection (LOD, S/N=3) of 0.05-0.10 nmol/L, and the spiked recoveries were 95.6%-101.4%.The results showed that the edible oils obtained from supermarket almost had no hexanal, heptanal, octanal, nonanal, decanal, but these aldehydes increased significantly in gutter oil.Thus the 5 kinds of long-chain aldehydes could be used as the indictor of gutter oil.Taking the advantage of good specificity, higher sensitivity, good accuracy and simplicity, the method was suitable for the rapid identification of gutter oil.