微波消解-AAS法分析银杏叶中金属元素

Determination of Metals in Ginkgo Biloba Leaves by Atomic Absorption Spectrometry with Microwave Digestion

采用微波消解技术处理银杏叶样品,用硝酸和双氧水（4∶1,φ）的混合消化液作为消解剂进行微波消解,原子吸收光谱法测定了同一区域同一树龄6颗不同植株银杏叶中钙、镁、钾、钠、铜和锌含量以及Zn/Cu值,以研究同一区域不同植株中金属元素分布规律。方法加标回收率在95.2%~104.6%之间。研究结果表明,同一地区同一树龄不同植株银杏树叶金属含量分布有差异。在6颗植株中钙含量为39 586~48 320μg.g-1,镁含量为10 076~12 918μg.g-1,钾含量为2 004~5 240μg.g-1,钠含量为9.05~35.30μg.g-1,铜含量为1.50~3.05μg.g-1,锌含量为6.70~8.90μg.g-1,Zn/Cu值为2.68~5.93。由此可见银杏叶中钙、镁、钾元素含量丰富,钠含量和Zn/Cu值较低。研究结果为探讨银杏叶中金属元素分布规律、金属元素与治疗心脑血管疾病的关系等提供了有用的数据。

Microwave digestion technique was used in the decomposition of Ginkgo biloba leaves from six different trees at the same age in the same area. HNO3-H2O2（5 ： 1 v/v） was used as microwave digestion agent at a suitable temperature and time. The contents of Ca, Mg, K, Na, Cu, Zn and Zn/Cu were determined by flame atomic absorption spectrometry to study the distribution rule of metallic elements in the trees at the same age and in the same area. The recovery ratio ranged from 95.2% to 104.6%. The results showed that there were certain differences between different trees in the distribution of metallic elements. The contents of calcium were from 39 586 to 48 320μg·g^-1, and those of magnesium from 10 076 to 12 918 μg · g^-1, of potassium from 2004 to 5 240μg·g^-1, of sodium from 9.05 to 35.30μg·g^-1, and of copper froml. 50 to 3.05 μg·g^-1, while Zn/Cu values were from 2. 68 to 5, 93 in the leaves of 6 different trees in the same growing area. Therefore there were abounding calcium, magnesium and potassium, while the content of sodium and Zn/Cu values were lower, and the metal contents were different in the leaves. The experimental results provided useful bases for studying the distribution rule of metallic elements in Ginkgo biloba leaves, the relationship between the contents of calcium, magnesium, potassium and sodium and the Zn/Cu value in ginkgo biloba leaves and the treatment for cardio-cerebral vascular disease.