胡曉榮， 劉  健， 周  莉
（成都理工大學(xué)材料與化學(xué)化工學(xué)院，四川 成都 610059）
摘  要：在pH 4.7的醋酸-醋酸鈉緩沖體系中，自紫甘藍(lán)中提取并經(jīng)純化的花青素與Al3+和Fe3+發(fā)生絡(luò)合反應(yīng)，花青素和兩種絡(luò)合物最大吸收波長分別為550，585，630 nm。利用吸光度的加和性，建立起鋁和鐵混合溶液在585 nm和630 nm波長處的工作曲線方程組，鋁和鐵含量在0.1～1.0  mg/25 mL范圍內(nèi)與吸光度呈良好的線性關(guān)系，相關(guān)系數(shù)大于0.995，絡(luò)合物摩爾吸光系數(shù)大于103 L·mol-1·cm-1。方法定量檢出限鋁為47.71 μg/25 mL、鐵為26.12 μg/25 mL。方法應(yīng)用于國家土壤標(biāo)準(zhǔn)樣品（GBW07408）的測定獲得準(zhǔn)確結(jié)果，土壤樣品加標(biāo)回收率鋁在96.1%~108.0%之間、鐵在95.4%~108.1%之間，土壤樣品測定精密度符合光度法要求。該方法干擾離子較少、顯色時(shí)間短、絡(luò)合物穩(wěn)定，可用于低常量和微量鋁和鐵的同時(shí)測定。
關(guān)鍵詞：分光光度法；花青素；鋁；鐵
中圖分類號：O625.31；O657.32；O614.81+1；O614.3+1    文獻(xiàn)標(biāo)志碼：A     文章編號：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