胡晓荣， 刘  健， 周  莉
（成都理工大学材料与化学化工学院，四川 成都 610059）
摘  要：在pH 4.7的醋酸-醋酸钠缓冲体系中，自紫甘蓝中提取并经纯化的花青素与Al3+和Fe3+发生络合反应，花青素和两种络合物最大吸收波长分别为550，585，630 nm。利用吸光度的加和性，建立起铝和铁混合溶液在585 nm和630 nm波长处的工作曲线方程组，铝和铁含量在0.1～1.0  mg/25 mL范围内与吸光度呈良好的线性关系，相关系数大于0.995，络合物摩尔吸光系数大于103 L·mol-1·cm-1。方法定量检出限铝为47.71 μg/25 mL、铁为26.12 μg/25 mL。方法应用于国家土壤标准样品（GBW07408）的测定获得准确结果，土壤样品加标回收率铝在96.1%~108.0%之间、铁在95.4%~108.1%之间，土壤样品测定精密度符合光度法要求。该方法干扰离子较少、显色时间短、络合物稳定，可用于低常量和微量铝和铁的同时测定。
关键词：分光光度法；花青素；铝；铁
中图分类号：O625.31；O657.32；O614.81+1；O614.3+1    文献标志码：A     文章编号：1674-5124（2013）03-0038-04
Simultaneous spectrophotometric determination of trace aluminum and iron by
using anthocyanin extracted from red cabbages
HU Xiao-rong， LIU Jian， ZHOU Li
（College of Material and Chemistry & Chemical Engineering，Chendu University of Technology，
Chengdu 610059，China）
Abstract: In the pH 4.7 acetic acid sodium buffer system， Al3+ & Fe3+ and anthocyanins which extracted from the red cabbage were reacted to form stable complexes. A new method was created to simultaneously determine Al and Fe with the absorbance of the complexes at the maximal absorption wavelength， i.e.， 550 nm， 585 nm and 630 nm. There was well linear relationship between the absorbance and the Al & Fe concentration in the range of 0.1~1.0 mg/25 mL， correlation coefficient was more than 0.995. The molar absorption coefficient of complex exceeded 103 L· mol-1·cm-1. The limit of quantification was 47.71 μg/25 mL for Al and 26.12 μg/25 mL for Fe respectively. The analytical procedure was critically evaluated by analyzing certified soil reference materials （GBW07408） and determining the recovery of Al and Fe in the materials. Excellent agreement between the experimental values and the certified concentrations was obtained， and the optimum recoveries of 96.1%~108.0% and 95.4%~108.1% were obtained for Al and Fe respectively through adding the standard solution in the digestion solution of the soil reference materials. The precision of replicate measurements could meet the request of spectrophotometric determination. Because of less interference ions， short colored time， stable complexes， this method can be used for the quantitative determination of trace amounts and low levels of aluminum and iron simultaneously.
Key words: spectrophotometry； anthocyanins； aluminum； ferrum