高效液相色谱法同时测定小麦粉中过氧化苯甲酰和苯甲酸及其含量稳定性考察

Determination of benzoyl peroxide and benzoyl acid in wheat flour products and their content stability

目的建立高效液相色谱法同时测定小麦粉中过氧化苯甲酰(benzoyl peroxide,BPO)和苯甲酸(benzoyl acid,BA)的方法并进行过氧化苯甲酰稳定性考察。方法直接提取样品中过氧化苯甲酰和苯甲酸并用高效液相色谱法直接同时测定,考察在不同基质类型、浓度水平、不同阶段中过氧化苯甲酰在样品储存过程中的动态变化与稳定性。结果相对标准偏差(relative standard deviation;RSD)<10%,在工作液浓度范围0.05(苯甲酸为0.10μg/m L)～100.00μg/m L具有良好的线性关系(r^2>0.999),空白基质加标量1 mg/kg时苯甲酸、过氧化苯甲酰回收率分别为91.2%、100.4%,其他加标量苯甲酸回收率范围99.1%～109.9%;在阴性基质加标水平分别为20、10、5 mg/kg时,30 d后BPO直接测定含量的总体降低比率分别为33.4%、16.3%、8.1%,呈不断降低趋势。结论新方法可更准确地掌握过氧化苯甲酰在样品和前处理与检测过程的转化情况,可得到更可靠的评判数据,避免现有检测方法定性和定量不确切的缺陷。

Objective To establish a method for simultaneous determination of benzoyl peroxide（BPO） and benzoyl acid（BA） in wheat flour products and to investigate the stability of benzoyl peroxide. Methods The benzoyl peroxide and benzoic acid in the sample were directly extracted and directly determined by high performance liquid chromatography. The dynamic changes and stability of benzoyl peroxide during sample storage in different matrix types, concentration levels and different stages were investigated. Results Relative standard deviations（RSDs） of this method were less than 10%, and it had good linear relationships in the working solution concentration range of 0.05（benzoic acid 0.10 μg/m L） to 100.00 μg/m L（r^2〉0.999）. The recoveries of benzoic acid and benzoyl peroxide were 91.2% and 100.4% at the spike level of 1 mg/kg, respectively. The recoveries of other spiked benzoic acid ranged from 99.1% to 109.9%. When the spiked levels of negative matrix were 20, 10, and 5 mg/kg, the overall reduction rates of BPO directly measured after 30 d were 33.4%, 16.3%, and 8.1%, respectively, which showed a decreasing trend. Conclusion The new method can more accurately grasp the conversion of benzoyl peroxide in the sample and pretreatment and detection process, and obtain more reliable evaluation data to avoid the defects of qualitative and quantitative inaccuracy of existing detection methods.