面制品中过氧化苯甲酰和苯甲酸的测定及热稳性研究

Study on the Determination and Thermal Stability of Benzoperoxide and Benzoic Acid in Flour Products

建立一种同时测定面制品中过氧化苯甲酰(BPO)和苯甲酸(BA)的高效液相色谱法,采用液氮冷冻干燥,将面制品预处理后采用无水乙醇进行提取BPO及BA后,用Tech Mate C_(18)色谱柱(5μm,250 mm×4.6 mm),以乙腈-乙酸(pH2.8)水溶液等度洗脱,检测波长233 nm,该方法在0.05~200mg/L范围内具有良好的线性特征(R_(BPO)=0.99987,R_(BA)=0.99994)。通过基质加标,BPO回收率介于90.2%~96.5%之间,相对标准偏差介于1.5%~3.4%之间,BA回收率介于91.5%~101.3%之间,相对标准偏差介于1.1%~3.6%之间,LODBA值为0.5 mg/kg,LOD_(BPO)值为0.8 mg/kg,说明该方法可行。同时,模拟样品在煮沸情况下BPO和BA的变化情况,得出BPO热稳性较差,在一定条件下分解产生BA。

A HPLC method was established for determination of benzoperoxide and benzoic acid in flour products simultaneously.Benzoperoxide and benzoic acid were extracted by anhydrous ethanol after pretreatment with freezing drying.The analysis was carried on a C18column(5μm,250mm4.6mm),gradient elution with a mixture of acetonitrile and pH=2.8acetic acid aqueous solution at the wavelength of233nm.The results showed that between0.05~200mg/L,the linearity of the method was good(RBPO=0.99987,RBA=0.99994).Under the spiked levels,the recoveries of benzoperoxide and benzoic acid were88.5%~96.5%and89.6%~101.3%respectively.The RSD of them were1.5%~3.4%and1.1%~3.6%respectively,and the limit of detection of them were0.8mg/kg and0.5mg/kg respectively.So this method was feasible.Meanwhile,changes of benzoyl peroxide and benzoic acid under the condition of boiling were simulated.The results showed that the thermal stability of benzoperoxide was poor and would be transformed into benzoic acid under certain conditions.