碱提取-电感耦合等离子体质谱法测定食品中的碘

Determination of iodine content in food by inductively coupled plasma-mass spectrometry with alkali extraction

目的建立碱提取-电感耦合等离子体质谱法测定食品中碘含量。方法样品经5%四甲基氢氧化铵(tetramethylammonium hydroxide,TMAH)溶液于85℃±5℃提取3 h,离心后取上清液,以铼作为内标,采用电感耦合等离子体质谱法(inductively coupled plasma-mass spectrometry,ICP-MS)测定。结果在0.5~50μg/L的线性范围内,回归方程呈现良好的线性关系,r=0.9998。该方法检出限为0.003 mg/kg,定量限为0.01 mg/kg,回收率为94%~102%之间,相对标准偏差小于10%。结论该方法操作简单,灵敏度高,适用于食品中碘含量的测定。

Objective To establish a method for determination of iodine content in food by inductively coupled plasma-mass spectrometry with alkali extraction.Methods Samples were extracted by 5%tetramethylammonium hydroxide(TMAH)at 85℃±5℃for 3 h.The supernatants after centrifugal were determined by inductively coupled plasma-mass spectrometry(ICP-MS)with Re as internal standard.Results The calibration curve showed good linear relationship in the range 0.5-50μg/L with good correlation coefficients(r=0.9998).The limit of detection was 0.003 mg/kg and the limit of quantification was 0.01 mg/kg.The spiked recoveries were 94%-102%,the relative standard deviation was less than 10%.Conclusion This method is simple and sensitive,it is suitable for the determination of iodine in food.