高效液相色谱柱后衍生测定脱水蔬菜中的亚硫酸盐

建立了检测脱水蔬菜中亚硫酸盐的反相硅胶柱净化-柱后衍生-高效液相色谱方法.样品经甲醛提取,通过反相硅胶固相萃取小柱净化,采用Discover ODS-C18柱,流动相为0.005 mol/L氢氧化四丁基铵和乙腈,在碱性条件下以5,5’-二硫代双(2-硝基苯甲酸)为柱后衍生化试剂,445 nm检测.实验结果表明,在0.050～50.00 mg/L浓度范围内,相关系数为0.9987,方法的检出限和定量限分别为1 mg/kg和2 mg/kg,添加浓度在2～900mg/kg范围内,平均添加回收率为62％～88％,相对标准偏差不大于7.8％.该法能有效地避免脱水蔬菜中亚硫酸盐测定的假阳性结果,可满足实际检测工作的需要.

Determination of Sulfite in Dehydrated Vegetable by High Performance Liquid Chromatography with Post-Column Derivatization

A method was established for determinaton of sulfite in dehydrated vegetable by HPLC after reversed-phase silica gel column clean-up and post-column derivatization.The dehydrated vegetable sample was extracted with formaldehyde and was purfied by LC-C18 solid-phase extraction column.The separation was performed on a Discover ODS-C18 column with a mixture of tetrabutylammonium acid-acetonitrile as the mobile phase and 5,5′-dithiobis(2-nitrobenzoic acid) as the derivatization reagent.The detection wavelength was 445 nm.The linear range was 0.050~50.00 mg/L and the correlation coefficient was 0.9987.The limits of detection(S/N=3) and quantitation(S/N=10) of sulfite were 1 mg/kg and 2 mg/kg,respectively.The recoveries ranged from 62%~88% with the relative standard deviations less than 7.8% at spiked levels of 2~900 mg/kg.The method prevented the possibility of the false positive,and could meet the need of the practical measurement.