A new high sensitive spectrophotometric method was developed for determination trace iron. The method was based on the reaction of Fe (III) with SCN(I ) and Rhodamine B, which forms a stable blue ternary ion complex system in sulfuric acid medium in the presence of poly vinyl alcohol and gelatin. The most absorption wavelength for 620 nm,the linear regression equation is y =0. 924a;+0. 281 3 , the correlation coefficient is 0. 999 4, and apparent molar absorptivity is 3. 38 x 106 L · (mol · cm)-1, with detection limit of 0, 025 p,g/L ,the linear range was 0～0.8μg/25 mL,this method is high sensitivity, selectivity and simplicity. Samples of mineral water, grape wine and beer were analyzed by this method for their Fe( M ) contents. The results obtained were in conformity with the results found by FAAS,the relative standard deviations( RSD)of determinations were 1.3% ～3.1% and recoveries were 98% ～ 101% .%在硫酸介质中,在聚乙烯醇和明胶的共同作用下,铁(Ⅲ)与硫氰酸根离子形成的络阴离子能与罗丹明B形成蓝色离子缔合物,据此建立了测定痕量铁的高灵敏光度分析方法.缔合物的最大吸收波长为620 nm,线性回归方程为y=0.924x +0.2813,相关系数为0.9994,表观摩尔吸光系数为3.38×106 L·(mol·cm-1),检出限为0.025 μg/L,铁(Ⅲ)浓度在0～0.8μg/25 mL范围内与吸光度(A)有良好的线性关系,该法灵敏度高、选择性和重现性好,用于红酒、啤酒和矿泉水中铁的测定,所得结果和火焰原子吸收光谱法结果相符,测得值的相对标准偏差为1.3％～3.1％,回收率为98％～101％.
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