ICP-MS法和GF-AAS法测定饲料级腐植酸钠中铅、镉、铬含量的比较研究

Research and comparison between ICP-MS method and GF-AAS method for determination of Pb,Cd and Cr in feed grade sodium humate

为了测定饲料级腐植酸钠中铅、镉、铬三种重金属元素的含量,试验采用全自动石墨消解仪消解腐植酸钠样品后,再分别用电感耦合等离子体质谱(ICP-MS)法和国家标准方法——石墨炉原子吸收光谱(GF-AAS)法测定,同时对这两种方法进行了比较分析。结果表明:ICP-MS法和GF-AAS法均能对饲料级腐植酸钠中铅、镉、铬三种重金属元素进行很好的分析检测,各元素校正曲线的相关系数均能达到或超过0.9987,线性关系良好;各元素检出限均等于或小于0.0062 mg/kg,灵敏度较高;加标回收率范围在90.1%~104.7%之间,回收率良好;相对标准偏差(RSD)均小于5.00%,精密度高;质控样品测定值的平均值均在标示值范围内,准确性良好。针对铅、镉、铬三种元素的检测,与GF-AAS法相比,ICP-MS法检出限更低,灵敏度更高,加标回收率表现更优,精密度和稳定性更佳。说明ICP-MS法和GF-AAS法均可用于对饲料级腐植酸钠样品中铅、镉、铬三种重金属元素进行分析检测;ICP-MS法具有更低的检出限,更高的灵敏度和更优的加标回收率和精密度,且一次进样可以同时得到多种元素的检测结果,简便快捷,更能满足生产中大批量快速检测的需求。

In order to detect the contents of the three heavy metal elements(Pb,Cd and Cr)in feed grade sodium humate,the samples were digested by automatic graphite digester,and then determined by inductively coupled plasma mass spectrometry(ICP-MS)method and the natioral standard method graphite furnace atomic absorption spectrometry(GF-AAS)method,respectively.At the same time,the two methods were compared and analyzed.The result showed that the contents of the heavy metal elements(Pb,Cd and Cr)in feed grade sodium humate both could be detected by the ICP-MS method and the GF-AAS method.The linear correlation coefficients were reached and even exceeded 0.9987,the linear relationship of the methods was good.The method detection limits were all equal to or less than 0.0062 mg/kg,the two methods both had good sensitivity.The standard recovery rates of 3 elements ranged from 90.1%-104.7%with good recoveries.The relative standard deviations(RSD)were less than 5.00%,so the two methods both had high precision.And the detected results of the quality control samples were within the marked value range,so the two methods both had good accuracy.For the detection of Pb,Cd and Cr,compared with GF-AAS method,the ICP-MS method has lower detection limit,higher sensitivity,better recovery rate,higher precision and better accuracy.The results indicated that ICP-MS method and GF-AAS method could be used for the determination of Pb,Cd and Cr in feed grade sodium humate samples.ICP-MS method has a lower detection limit,higher sensitivity and better recovery rate and precision,and the detection results of multiple elements can be obtained at the same time with one injection.The method is simple and fast,and can better meet the needs of rapid mass detection in production.