蒸发光散射检测器和示差检测器应用于食品中三氯蔗糖测定的比较

Comparison between evaporative light scattering detector and refractive index detector for the determination of sucralose in food

目的比较高效液相色谱示差检测法和高效液相色谱法蒸发光散射检测法检测多种食品中三氯蔗糖含量的分析方法。方法样品经甲醇溶液提取后,除蛋白、脂肪后,经亲脂性二乙烯苯和亲水性N-乙烯基吡咯烷酮固相萃取小柱净化,富集后采用高效液相色谱仪进行检测。仪器条件如下:示差检测器:等度洗脱,检测池温度35℃;灵敏度:16;蒸发光散射检测器:梯度洗脱,雾化器温度:30℃;雾化器压力:1 psi;蒸发室温度:80℃;增益:1; N_2流量:1.0 L/min。结果三氯蔗糖在5、10和50 mg/kg添加水平的示差检测器回收率的结果为84.3%～99.6%,相对标准偏差小于6.9%(n=6);蒸发光散射检测器:回收率的结果为85.6%～98.9%,相对标准偏差小于8.1%(n=6);方法检出限为2 mg/kg,定量限为5 mg/kg。结论 2种方法均可有效检出食品中的三氯蔗糖,蒸发光散射检测器采用双对数线性回归。

Objective To compare the determination of sucralose in multiple categories of food by high performance liquid chromatography-refractive index detector（HPLC-RID） method and high performance liquid chromatography-evaporative light scattering detection（HPLC-ELSD） method. Methods The sample was extracted by methanol solution and purified by solid phase extraction cartridge（HLB） after removal of protein and fat. After enrichment, the sample was detected by high performance liquid chromatography. The instrument conditions are as follows： refractive index detector： elution method was isocratic, detection cell temperature was 35 ℃, sensitivity was 16; evaporative light scattering detector： gradient elution, nebulizer temperature was 30 ℃, evaporation chamber temperature was 80 ℃, gain value was 1, N_2 flow was 1.0 L/min. Results At 3 spiked levels of 5, 10 and 50 mg/kg, the recoveries of refractive index detector were ranged from 84.3% to 99.6%, the relative standard deviations（RSDs） were less than 6.9%（n=6）, the recoveries of evaporative light scattering detector were ranged from 85.6% to 98.9%, RSDs were less than 8.1%（n=6）, the limits of quantitation（LOD） for sucralose was 2 mg/kg, and the limit of quantitative was 5 mg/kg. Conclusion Both two methods can effectively detect sucralose in food, and the evaporative light scattering detector adopts double logarithmic linear regression.