小麦粉制品中氨基脲的检测及与偶氮甲酰胺的转化规律研究

Study on the determination of semicarbazide in flour products and the transformation law between azodicarbazide and semicarbazide

目的建立用超高效液相色谱-串联三重四级杆质谱仪(UPLC-MS/MS)检测小麦粉制品中的氨基脲的定性定量方法,并研究了偶氮甲酰胺添加水平对面包中氨基脲含量的影响及两者的转化条件。方法在偏酸性条件下将样品水解,经邻硝基苯甲醛衍生乙酸乙酯提取,采用电喷雾电离,正离子扫描,用带有同位素内标的衍生物15N132C-SEMNBA定量检测目标氨基脲衍生物,优化液相色谱质谱检测条件,内标法定量。结果氨基脲的浓度为0.5μg/kg^100μg/kg时,线性关系良好,线性方程为y=352x+383,相关系数(r)为0.999 5,检出限为0.5μg/kg,加标回收率为85.1%~114.6%,相对标准偏差(RSD)为3.2%~6.9%。市售面制品中氨基脲的阳性检出率为41.7%。结论本方法快速、准确、灵敏度高,适用于面制品中氨基脲的定量分析。实验证明氨基脲是偶氮甲酰胺在湿热的条件下生成的,并且同一种小麦粉制品中样品外部的氨基脲含量比内部含量大。

Objective To develop a quantification and qualification method for the determination of semicarbazide in flour products by liquid chromatography- tripe quadrupole tandem mass spectrometry（ UPLC- MS / MS）,and to study the effect of azodicarbazide addictive levels on the semicarbazide content in flour as well as their transform conditions. Methods The samples were hydrolyzed under the acidic solution,derivated with 2- NBA,extracted with ethyl acetate,ionized using electrospray ionization and described with positive ion,then quantified the target of the derivatives of SEM with isotope internal standard15N132C-SEM- NBA. The condition of liquid chromatography mass spectrometry was optimized and the internal standard method was quantitative. Results Good linearity was obtained when the concentration of semicarbazide was within 0. 5 μg / kg- 100 μg / kg;the linear equation was y = 352 x ＋ 383,with the correlation coefficient（ r） of 0. 999 5,the detection limit of 0. 5 μg / kg. The recovery rates were within 85. 1%- 114. 6%,with the relative standard deviations（ RSDs） of 3. 2%- 6. 9%. The positive rate of semicarbazide in the commercial flour products was 41. 7%. Conclusion This method is fast,precise and sensitive. It is suitable for the quantitative determination of semicarbazide in flour product. Experiments shows that azodicarbazide transforms semicarbazide under the hot and heat condition,and the semicarbazide content on the surface is higher than that inside the same flour product.