提出了微波辅助衍生-离子液体分散液液微萃取-高效液相色谱法测定发酵酒和饮料中的甲醛。以2,4-二硝基苯肼为衍生试剂,1-辛基-3-甲基咪唑六氟磷酸盐为提取剂,乙腈为分散剂,样品溶液在300 W的微波功率下辐照60 s后离心,甲醛衍生物被萃取到离子液体中,用乙腈定容。以SB-C18色谱柱为分离柱,以水-甲醇(2+8)溶液为流动相进行洗脱,检测波长355 nm。甲醛的质量浓度在1.00~100 μg·L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)为0.16 μg·L-1,测定下限(10S/N)为0.53 μg·L-1。对啤酒、葡萄酒、可乐和橙汁4个样品进行加标回收试验,回收率在92.5%~99.1%之间,测定值的相对标准偏差(n=5)在2.6%~7.8%之间。

A method based on HPLC coupled with microwave-assisted derivatization and ionic liquid-based dispersive liquid-liquid microextraction (DLLME) was developed for determination of formaldehyde in fermented wine and beverage. 2,4-dinitrophenylhydrazine (DNPH) was used as the derivatization reagent, 1-octyl-3-methylimidazolium hexafluorophosphate as extraction solvent, and acetonitrile as disperser. The sample solution was then irradiated at 300 W of microwave power for 60 s and centrifuged. Formaldehyde derivatives were extracted into the ionic liquid, and then dispersed in acetonitrile for HPLC analysis. The SB-C18 column was used as stationary phase and a mixture of water and methanol as mobile phase. UV-detection was measured at 355 nm. The linear relationship between the peak area and the mass concentration of formaldehyde was in the range of 1.00-100 μg·L-1, with detection limit (3S/N) of 0.16 μg·L-1 and limit of quantification (10S/N) of 0.53 μg·L-1. Tests for recovery were made by adding standard samples to draft beer, wine, cola and orange juice samples, giving recovery rates in the range of 92.5%-99.1% and RSD (n=5) in the range of 2.6%-7.8%.