小麦粉中过氧化苯甲酰与苯甲酸总量的毛细管气相色谱法测定

Determination of Total Amount of Benzoyl Peroxide and Benzoic Acid in Wheat Flour by Capillary Gas Chromatography

报道了测定小麦粉中作为增白剂的过氧化苯甲酰及残留苯甲酸总量的改进方法。小麦粉通过酸性乙醚 石油醚 (6 0～ 90℃ )萃取 ,其中过氧化苯甲酰同时被还原成苯甲酸 ,经石英毛细管气相色谱柱DB WAX分离 ,氢火焰离子化检测器检测 ,以外标法定量。方法的相对标准偏差为 4 .8%～ 9.1% ;线性范围为 0 .0 0 5～ 0 .1g/L(r =0 .996 ) ;检出限为 2 .0mg/L ;回收率为 90 .0 %～ 96 .5 %。将该法应用于小麦粉中过氧化苯甲酰及残留苯甲酸总量的分析 。

An improved method for the determination of total amount of benzoyl peroxide (BPO) and benzoic acid (BA) in wheat flour is reported. The two components were efficiently extracted from wheat flour with mixed solvent of acidic ethyl ether and petroleum ether(60～90℃), and then analyzed by gas chromatography on a silica capillary column DB-WAX(60 m×0.32 mm id.,0.25 μm) and with a flame ionization detector. External standard method was used for the quantitative analysis. The RSD of the method was 4.8%～9.1%. The linear range of the method was 0.005～0.1 g/L(r=0.996). Minimum detectable limit at a signal-to-noise of 2∶1 was 2.0 mg/L. The recovery was in the range of 90.0%～96.5%. The method has been used to determine total amount of BPO and BA in wheat flour with satisfactory results.