铁(Ⅱ)-4-(2-苯并噻唑偶氮)连苯三酚体系间接光度法测定V_C

INDIRECT SPECTROPHOTOMETRIC DETERMINATION OF VITAMIN C BY FE(Ⅱ)-BTATB-SYSTEM

在β-环糊精(β-CD)和曲拉通X-100(TritonX-100)存在下,依据抗坏血酸可定量将Fe(Ⅲ)还原为Fe(Ⅱ),Fe(Ⅱ)与4-(2-苯并噻唑偶氮)连苯三酚(BTATB)形成有色络合物,建立了测定抗坏血酸的新方法。配合物的最大吸收波长为650nm,表观摩尔吸光系数为2.40×105,VC含量在0μg/mL￣0.8μg/mL范围内服从比尔定律,线性回归方程:y=0.0856x+0.0012,r=0.9982。本方法已用于水果蔬菜中VC的测定,结果令人满意。

A new sensitive method was established based on Fe（m） is reduced by Vitamin C to form Fe（ Ⅱ ）-BTATB association, in the presence of β-CD and TritonX- 100, the maximum absorbance is at 650 nm with apparent molar absorption of 2.40 × 10^5.The beer＇s law is obeyed in the range of 0 μg/25 mL-20 μg/25 mL. The regression equation of calibration is y = 0.085 6 x＋0.001 2,r = 0.998 2（μg/25 mL）, with a correlation coefficient of 0.998 2. The method can be used for the determination of trace Vitamin C in fruits and vegetables with satisfactory results.