Determination Of Trace Pb, Cd, Cu In Chinese Herbal Medicine By Flame Atomic Absorption Spectrometry After Separation/Preconcentration With Mesoporous Al₂O₃

The hyphenated technique of flame atomic spectrometry （FAAS） withsolid-phase extraction（SPE） has been used in this paper，in order to determine thecontent of the trace heavy metal elements in traditional Chinese herbal medicine. Thetechnology improves the selectivity and sensitivity of analysis method, but alsoreduces the matrix interference. The key in this paper is mesoporous separationmaterial, it is a hot separation material with a high adsorption performance at present.This thesis in a reference on the basis of Chinese and foreign literature has synthetizeda kind of high efficient adsorption materials which is mesoporous Al₂O₃, and with theflame atomic absorption as a method for detection.It has studied the process ofseparation and concentration of heavy metal ion in lead, copper and cadmium inChinese herbal medicine with mesoporous Al₂O₃, and has set up a new method ofhigh efficiency analysis of trace heavy metal element in traditional Chinese medicinalmaterials.The major contents were described as follows:1. The main determination method of heavy metals in Chinese traditionalmedicine were reviewed.The research and application during the adsorption materialsand the technology of separation/enrichment in heavy metal analysis also werereviewed. The review emphasized on the mesoporous ma terials properties, synthesisand applications, and then came up with a new method of studying of trace Pb, Cd,Cu in Chinese herbal medicine determined by flame atomic absorption spectrometryafter separation/preconcentration with mesoporous Al₂O₃.2. A mesoporous adsorption Al₂O₃was self-made with sol-gel method and then itwas characterized. The average pore diameter is6.495nm and the specific surfacearea is224.595m²/g. We has studied the mesoporous Al₂O₃on lead adsorptionproperties under static conditions. The experiment discussed the solution acidity,temperature, time and the eluent on the separation and preconcentration of lead effects.Under the optimal experimental conditions, the interference of co-existing ions andadsorption of repetitive use experiment, and get the static saturated adsorptioncapacity of8.53mg/g. This method can be applied to Chinese herbal ephedra andsemen samples in the determination of trace lead.3. A mesoporous adsorption Al₂O₃was self-made with sol-gel method usingFAAS as a means of detection, and discussed the mesoporous Al₂O₃in dynamicconditions of Chinese herbal medicine blue root and platycodon grandiflorum of trace cadmium The linear range for cadmium is0.1².0μg/mL.The method of the detectionlimit （3σ） was10.3ng/mL, and the relative standard deviation （RSD） was1.87%（n=7, c=1.0μg/mL）.The recoveries were90.0%¹18.0%,with satisfactory results.4. Mesoporous Al₂O₃loaded1-（2-pyridine azo）-2-alpha-naphthol （PAN） wassynthetise. Adsorption property of mesoporous Al₂O₃loaded PAN for trace copper inthe dynamic conditions was investigated. The linear range is0.05⁶.0μg/mL;detection limit （3σ, n=7）6.62ng/mL; relative standard deviation was2.4%.Themethods was applied to Chinese traditional medicine samples radix ophiopogonis andwhite ginseng tail in the recovery between96.0%to104.7%and the results weresatisfactory.