摘要
建立了溶剂萃取PAN光度法测定茶叶中铁形态的新方法。显色剂PAN与铁（Ⅱ）在pH1的介质中络合显色，Fe（Ⅲ）在此酸度下不显色，以甲基异丁酮为萃取剂，将Fe^2＋-PAN萃取到有机相，实现铁（Ⅱ）和Fe（Ⅲ）的分离。文中详细研究了铁（Ⅱ）的显色和萃取条件：在pH1．0显色10min后，用5mL的甲基异丁酮振荡萃取15min，分液后测定机相的吸光度。体系中加入还原剂，测定总铁的量。铁在0～20μg／5mL范围内呈线性关系，摩尔吸光系数为1．51×10μL·mol^-1·cm^-1。该法用于测定茶叶水中的形态铁结果令人满意。
A novel method for separation and speciation of iron species has been developed by using sol- vent extraction. The complex Fe^2＋ -PAN is formed at pHI. 0. MIBK is employed to extract the complex from aqueous solution, which separates Fe^2＋ from Fe^3＋ and reduces speciation transformation between the two oxidation states. Optimal conditions for reaction and extraction are studied in this article. Fe^2＋ -PAN is extracted with 5ml MIBK after 10min color - developing reaction. Iron is detected in organic phase. The total iron is estimated after introducing reducing reagent into the system. The linear range is 0 ～ 20 μg/SmL with the molar absorptivity of 1.51 × 10^4L · mol^-1 · cm^-1. Good results are obtained for tea infusion samples.
出处
《江西农业大学学报》
CAS
CSCD
北大核心
2006年第4期630-633,640,共5页
Acta Agriculturae Universitatis Jiangxiensis
基金
江西省自然科学基金资助项目(0520002)
