碘化钾-罗丹明6G分光光度法测定面粉中过氧化苯甲酰

Spectrophotometric Determination of Benzoyl Peroxide in Wheat Flour Using KI-Rhodamine 6G System

采用碘化钾-罗丹明6G分光光度法对面粉中过氧化苯甲酰(BPO)含量进行测定。在硫酸介质中,有聚乙烯醇存在下,过氧化苯甲酰氧化I-生成I3-,再与罗丹明6G形成离子缔合物,该缔合物在560nm波长处有最大吸收峰,在0.3～5.9mg/L范围内,BPO浓度与吸光度呈良好线性关系,线性方程为A=0.2174+0.0833c/(mg/mL),线性相关系数为0.9985,表观摩尔吸光系数为2.13×104L/(cm.mol)。该法用于两份市售面粉中过氧化苯甲酰的测定,平均回收率分别为96.5%和98.6%,并将测定结果与高效液相色谱测定结果进行对比,误差在5%以内,结果令人满意。

A sensitive spectrophotometric method has been developed for the determination of trace amounts of benzoyl peroxide（BPO） based on the oxidation of I-to I3-by BPO and the further reaction of I3-with rhodamine 6G to form an ion association complex in H2SO4 solution.The ion association complex had maximum absorption at 560 nm and its absorbance（A） showed a good linear relationship with BPO concentration（c,mg/mL） within the range of 0.3–5.9 mg/L： A = 0.2174 ＋ 0.0833 c,with a correlation coefficient of 0.9985.The calculated apparent molar absorption coefficient was 2.13 × 104 L/（cm·mol）.The average spike recovery rates of BPO in two commercial samples were 96.5% and 98.6%,respectively.Satisfying results were obtained in practical applications of this method with a relative error of less than 5% compared with HPLC results.