半消解电感耦合等离子体发射光谱法测定食品中的镉、铬

Determination of cadmium and chromium in food by inductively coupled plasma atomic emission spectrometry after incomplete digestion

目的建立一种电感耦合等离子体发射光谱(ICP-OES)测定半消解食品中镉、铬的方法。方法对3种食品进行湿法消解,样品在恒温电热板上120℃下消解1 h,冷却后直接以去离子水定容,最后采用ICP-OES进行检测,同时与石墨炉原子检测结果比较。采用国家标准方法对大米进行检测,将其结果与新方法进行t检验。结果通过对FAPAS标准样品的分析与原子吸收光谱(AAS)法的结果比较,确定了方法的准确度。镉加标回收率为90%~105%,铬加标回收率为88%~104%,Cd、Cr检出限均为50μg/kg。经过t检验比较,2种方法的检测结果差异无统计学意义。结论国家标准方法费时,用酸量较大,而本法对实验设备要求不高,操作相对简单,用时较短,结果理想,适用于食品中镉和铬的快速检测。

Objective To establish a method for the determination of cadmium and chromium in food by inductively coupled plasma optical emission spectrometry（ ICP-OES） after incomplete digestion. Methods Three kinds of food were conducted for wet digestion on the constant temperature electric heating plate at 120 ℃ for 1 hour,quantified with deionized water after cooling down and detected by ICP-OES. At the same time,the results were compared with that of AAS. Rice sample was analyzed by the method of Chinese National Standard and the new method. These two groups of date are statistically analyzed with t test. Results The accuracy of this method was verified by analysis of the standard samples of FAPAS and by comparison with the results of AAS. The average recovery of cadmium was within 90%-105%,the average recovery of chromium was within88%-104%. The detection limits of cadmium and chromium were both 50 μg/kg. The results of t test showed that there was no statistical significance on the difference between the two methods. Conclusion The method of Chinese National Standard is time-consuming and large quantity of acids were needed. The new method requires less experiment equipment and time,and the operation is relatively simple. The result is accurate and reliable. So it is suitable for the determination of Cd and Cr in food.