采用碘化钾-吖啶红分光光度法对小麦面粉中过氧化苯甲酰含量进行了测定。在硫酸介质中,有聚乙烯醇存在的情况下,过氧化苯甲酰氧化I-生成I3-,I3-与吖啶红发生离子缔合反应,导致KI-吖啶红-聚乙烯醇溶液体系的吸光度下降,在525 nm波长下,过氧化苯甲酰在0.04～6.0 mg/L内与吸光度的改变量呈线性关系,据此建立了测定小麦面粉中过氧化苯甲酰的碘化钾-吖啶红分光光度法,该法用于小麦面粉中过氧化苯甲酰的测定,平均回收率为98.2%与101.6%。

The spectrophotometric determination of benzoyl peroxide(BPO) in wheat flour by KI-Acridine Red-PVA system was established.It was found that in the H2SO4 medium,BPO reacts with KI to give I-3,which further reacts with acridine red to form an ion-association complex and causing the absorbance of the solution decreased.Under 525nm,a good linear relationship was found between the absorbance and concentration of BPO and the average recovery was 98.2% and 101.6% respectively.Based on these facts,a simple sensitive and accurate spectrophotometric method for the determination of BPO was proposed.It has the advantages including easy operation,high sensitivity,good precision,and low consumption etc.,which can meet the requirements to detect benzoy peroxide residue in wheat flour samples.