毛细管气相色谱法测定肠内营养粉剂中碘的含量

目的： 建立采用毛细管气相色谱测定肠内营养粉剂中碘的方法。 方法： 在酸性条件下过氧化氢将碘离子氧化为游离碘，游离碘与丁酮反应生成碘丁酮，再用正己烷萃取。采用气相色谱法，经RTX-225毛细管色谱柱分离，以电子捕获检测器检测。 结果： 碘浓度在0.002~0.020 μg·mL^-1范围内与衍生物峰面积的线性关系良好，r=0.9993（n=7）；高、中、低浓度平均加样回收率分别为98.6%、100.1%和100.0%，RSD分别为0.55%、0.33%与0.48%；检测限为0.008 ng·mL^-1，定量限为0.02 ng·mL^-1。 结论： 经方法学验证，此方法灵敏度高，专属性好，结果准确，可用于肠内营养粉剂中微量碘的测定。

Objective: To establish a capillary GC method for the assay of iodine in enteral nutritional powder. Methods: The iodine ion was oxidized to free iodine by hydrogen peroxide in acidic environment.Free iodine reacted with 2-butanone to produce iodobutanone,which was extracted with hexane after reaction.The assay was conducted by capillary gas chromatography on a RTX-225 capillary column with an electron capture detector. Results: There was a good linear relationship between the area of the derivative and the concentration of iodine.The linear equation was Y=1.077×10⁴X+61.30(r=0.9993) within the range of 0.002-0.020 μg·mL^-1.The recoveries of high,medium and low concentrations were 98.6%,100.1% and 100.0% (RSD=0.55%,0.33% and 0.48%,n=3),respectively.The LOD was 0.008 ng·mL^-1,and the LOQ was 0.02 ng·mL^-1. Conclusion: The method verified by methodology is sensitive,reliable and accurate amd can be used for the assay of enteral nutritional powders.