高效液相色谱法测定米粉中次硫酸氢钠甲醛(吊白块)

Determination of sodium formaldehyde sulphoxylate in rice flour by HPLC

少数米粉加工者违法加入次硫酸氢钠甲醛（吊白块）起到漂白、增色、改善食品口感及防腐等作用,但次硫酸氢钠甲醛可引起肺水肿、肝、肾充血及血管周围水肿,甚至可能致癌。利用高效液相色谱法可测定米粉中的次硫酸氢钠甲醛,确保消费者食用的米粉质量安全。该方法中样品经酸性溶液提取次硫酸氢钠甲醛分解得到的甲醛,与衍生试剂2,4-二硝基苯肼发生反应,经优化试验确定衍生时间为20min衍生效果最好,正己烷提取衍生产物,利用高效液相色谱测定,试验条件确定为乙腈：水（60：40）,流速为0.8mL/min,分离效果最好,利用标准甲醛衍生物保留时间对照定性,标准曲线定量测定次硫酸氢钠甲醛含量。该方法检出限为0.1μg/g,回收率在88.2%~96.1%。本文通过100份米粉样品的检测表明该法分析米粉中的次硫酸氢钠甲醛准确度和精密度均能满足检测工作要求,适合于大批量米粉中的次硫酸氢钠甲醛的测定。

A fewer manufacture use sodium formaldehyde sulphoxylate in rice flour to bleach,improve the texture and antisepsis the flour.But sodium formaldehyde sulphoxylate may raise pulmonary edema,hepatohemia,nephrohemia,angioedema and even the cancers.To ensure the food safety,high performance liquid chromatographic（HPLC）method was used to determine sodium formaldehyde sulphoxylate in rice flour.Formaldehyde extracted in the acidity solvent was decomposed into Dinitrophenylhydrazine,and then reacted with n-hexane to form the derivative which can be quantitatively detected by HPLC.The best time for the reaction was 20min.The best detecting condition was acetonitrile：water（60 ∶40）,the flow rate was 0.8mL/min.Use the retention time of standard formaldehyde derivative as the control to calculate the content of sodium formaldehyde sulphoxylate.The detection limit was 0.1μg/g in samples,and recovery was 88.2%～96.1%.The method was used to determinate 100 samples of rice flour from the city market and showed a good linear relationship,strong specialty,and good repetition.This method is suitable to determine the formaldehyde in rice flour with satisfactory results.