检测仪器及消解方式对罗布麻微量元素检测效果的影响

目的 探索罗布麻微量元素适宜的检测条件。方法 以新疆产罗布麻和白麻叶及其制品罗布麻茶为实验材料, 比较了电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry, ICP-MS)和电感耦合等离子体原子发射光谱法(inductively coupled plasma atomic emission spectrometry, ICP-AES)2种仪器对其Li、B、Cr、Fe、Mn、Cu、Zn、Se和Sr 9种微量元素的检测效果, 同时对比了3种不同的湿法消解方式对检测结果的影响。结果 采用不同酸解液的3种湿法消解方法, 硝酸/过氧化氢消解液处理条件较温和, 元素损失量较少, 检测结果稍高于浓硝酸/高氯酸消解液处理的结果, 但所耗消解时间更长。对于易挥发元素Se, 选用酸性和氧化性较弱的硝酸/过氧化氢消解液更适宜。在本试验条件下, 罗布麻体内的Li和Cr 2种微量元素不宜采用ICP-AES仪器检测, 可选用ICP-MS, 而对于难电离元素Se则正好相反。结论 检测罗布麻微量元素含量时, 应根据待检测元素类型特征, 选择适宜的检测仪器。

Effects of detection instruments and digestion methods on the detection of trace elements of Apocynum venetum

Objective To explore the suitable conditions for detecting trace elements of Apocynum venetum. Methods The leaves from Apocynum venetum Linnaeus and Apocynum pictum Schrenk and Apocynum venetum tea in Xinjiang were used as materials, and inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) were performed to comparatively detect their trace element content, including Li, B, Cr, Fe, Mn, Cu, Zn, Se and Sr. Moreover, the effects of 3 types of wet digestion on the microelement content were conducted. Results Totally 3 kinds of wet digestion methods using different acid hydrolysis solutions were used, the nitric acid/hydrogen peroxide digestion solution treatment conditions were milder, the element loss was less, the test results were slightly higher than the concentrated nitric acid/perchloric acid digestion solution treatment results, but it took longer time to digest. For volatile element Se, it was more suitable to use nitric acid/hydrogen peroxide digestion solution with weak acidity and oxidation. Under the conditions of this test, the 2 trace elements of Li and Cr in Apocynum were not suitable for detection by ICP-AES instruments, and ICP-MS could be selected, while the opposite was true for the hard ionized element Se. Conclusion When detecting the content of trace elements in Apocynum venetum, an appropriate detection instrument should be selected according to the characteristics of the type of elements to be detected.