微波消解ICP-OES法同时测定香茅草中11种微量元素

本研究首次建立了微波消解/电感耦合等离子体发射光谱仪(ICP-OES)同时测定香茅草中11种微量元素(Zn、Cd、Pb、Co、Ni、B、Mn、Fe、Cr、Mg、Cu)的方法,采用HNO₃-H₂O₂混合酸体系进行消解,样品消解完全彻底,并优化了微波消解程序和仪器工作参数。结果表明：待测11种元素的线性关系良好,相关系数(r)为0.9983~0.9999,检出限(LOD)为0.000050~0.081325 mg/L,定量下限(LOQ)为0.0002~0.2455 mg/L。供试样品平均回收率为90.00%~102.50%;相对标准偏差(RSD, n=6)为0.25%~1.64%。元谋和陇川香茅草中不同元素含量之间均存在显著差异,两地香茅草各元素含量高低顺序均为：Mg>Fe>Zn>Mn>Cu>Ni>B,而Cd、Pb、Cr、Co均未检出;同一元素含量在来源地不同的材料间也存在一定差异。该方法具备快速简便、准确度高、灵敏度高、稳定性好等优势,适用于香茅草样品中多元素的同时测定。

Simultaneous Determination of 11 Trace Elements in Cymbopogon citratus by ICP-OES with Microwave Digestion

In this study, a method was developed for the first time for simultaneous determination of 11 trace elements (Zn, Cd, Pb, Co, Ni, B, Mn, Fe, Cr, Mg, Cu) in Cymbopogon citratus by using inductively coupled plasma optical emission spectrometer (ICP-OES) with microwave digestion. Samples were digested completely by using HNO₃-H₂O₂ mixed acid. The instrumental working parameters and microwave digestion process were optimized. The results showed that: the linear relationship of 11 trace elements was good, the correlative coefficients were in the range of 0.9983-0.9999, the limits of detection (LOD) were in the range of 0.000050-0.081325 mg/L, the limits of quantification (LOQ) were in the range of 0.0002-0.2455 mg/L, the recovery rates were in the range of 90.00%-102.50%, and the relative standard deviations (RSD, n=6) were in the range of 0.25%-1.64%; the concentration of the 11 trace elements in Cymbopogon citratus from Yuanmou and Longchuan had significant differences, the order of was Mg>Fe>Zn>Mn>Cu>Ni>B, and Cd, Pb, Cr and Co were not detected; the concentration of the same element was also different among the samples from different sources. This method has the advantages of rapidness, simplicity, accuracy, high sensitivity and good stability, which is suitable for simultaneous determination of various elements in Cymbopogon citratus.