Fe(Ⅲ)-钛铁试剂褪色光度法测定沙田柚果肉中维生素C的含量  

Determination of VitaminC in Shatian Pomelo Pulp by Fe(Ⅲ)-Tiron Fading Spectrophotometry

作　　者：梁奇峰[1] 何江[1] 温欣荣[1] 

机构地区：[1]嘉应学院化学系,梅州514015

出　　处：《食品工业》2013年第5期216-218,共3页The Food Industry

摘　　要：在pH 2.6的邻苯二甲酸-邻苯二甲酸氢钾缓冲体系中,Fe(Ⅲ)与钛铁试剂形成最大吸收波长为669 nm的绿色配合物,其浓度与吸光度成正比。加入适量的维生素C将溶液中的Fe3+还原成Fe2+,溶液吸光度减小。测定溶液加入维生素C前后的吸光度分别记为A0,A,其吸光度变化为ΔA=A0-A。以ΔA与维生素C浓度CVc绘制标准工作曲线。在维生素C质量浓度5.0～45.0 mg/L的范围内,ΔA与cVC的线性回归方程为ΔA=0.020 7cVC-0.085 5,相关系数为R=0.999 7,方法检出限为0.116 mg/L。利用该法测得梅县沙田柚果肉维生素C的含量为110.2 mg/100 g,测定相对标准偏差为0.6%(n=6),测定回收率为102.8%～105.7%(n=6)。Green complex which had maximum absorption wavelength of 669 nm could be found in Fe（III） ion-tiron at pH 2.6. When Vitamin C was added into the system of Fe（III）-tiron in a acidic condition about pH 2.6, the Fe（III） ions were reduced to Fe（ II ） ions ,and the green complex＇s absorbance would fall down, The reduction of absorbance （zJA） had good linear relationship with the contents of Vitamin C from 5.0 mg/L to 45.0 mg/L. The linear regression equation was AA=0.020 7cvc-0.085 5 with correlation coefficient of 0.999 7, and the detection limit was 0.116 mg/L. The content of Vitamin C in Shatian pomelo pulp was 110.2 mg/100 g determined by this method. The relatively standard deviation was 0.6% （n=6）, and the recoveries of the method were from 102.8% to 105.7% （n=6）.

关 键 词：光度法测定 Fe(Ⅲ) 维生素C 钛铁试剂 沙田柚 果肉 邻苯二甲酸氢钾 褪色 

分 类 号：TS255.7[轻工技术与工程—农产品加工及贮藏工程]