电感耦合等离子体质谱法测定莲藕中的铅、镉、铬、砷和汞

目的 建立电感耦合等离子体质谱法同时测定莲藕中的铅、镉、铬、砷和汞含量的分析方法。方法样品经微波消解后,以209铋、115铟、72锗内标溶液消除非质谱干扰,以氦气为碰撞反应气消除质谱干扰。采用基准物质大米粉GBW(E)100348、菠菜GBW10015和加标回收率验证方法的准确度。对方法的线性范围、检出限、精密度和回收率等进行了考察。结果 铅、镉、铬、砷和汞5种元素的线性范围分别为0～50、0～50、0～50、0～50和0～2μg/L;相兲系数r分别为0.9996、0.9996、0.9991、0.9997和0.9990;平均加标回收率分别为97.3%、97.5%、95.7%、96.0%和97.4%;相对标准偏差分别为0.37%、0.89%、1.04%、1.03%、1.58%;检出限分别为0.001、0.002、0.002、0.001和0.0003mg/kg。结论 该方法操作简便,干扰较小,灵敏度高,同时检出限低、精密度高、准确度好,适用于同时检测莲藕中的铅、镉、铬、砷和汞。

Determination of lead, cadmium, chromium, arsenic and mercury in lotus root by inductively coupled plasma mass spectrometry

Objective To establish a method for simultaneous determination of lead, cadmium, chromium, arsenic and mercury in lotus root by inductively coupled plasma mass spectrometry. Methods Lotus root was digested by microwave. 209Bi, 115In and 72Ge were selected as the internal standard elements to overcome non-spectroscopic interference and helium was used as collision to eliminate mass spectroscopic interference. The accuracy was verified by using the national standard material rice, spinach and recovery test. The linear range, limit of detection, precision and recovery of the method were investigated. Results The linear ranges of lead, cadmium, chromium, arsenic and mercury were 0-50, 0-50, 0-50, 0-50 and 0-2 ug/L with the correlation coefficients r were 0.9996, 0.9996, 0.9991, 0.9997 and 0.9990, respectively. The average recoveries of Pb, Cd, Cr, As and Hg in samples were 97.3%, 97.5%, 95.7%, 96.0% and 97.4%, respectively. The relative standard deviations were 0.37%, 0.89%, 1.04%, 1.03%, and 1.58%, and the limits of detection were 0.001, 0.002, 0.002, 0.001 and 0.0003 mg/kg, respectively. Conclusion This method is suitable for simultaneous determination of lead, cadmium, chromium, arsenic and mercury in lotus root owing to easy operation, less interference, high sensitivity, low detection limit, high precision and good accuracy.