微波水解-HPAEC-PAD法快速测定乳粉中的皮革水解蛋白

Rapid determination of leather hydrolyzed protein in milk powders by microwave hydrolysis and HPAEC-PAD

L-羟脯胺酸是皮革水解蛋白的特征氨基酸。样品经微波酸水解使氨基酸游离,水解液过C18柱和0.22μm水系膜净化过滤,以AminoPacTMPA10阴离子交换柱为分离柱,采用NaOH/NaOAc/HOAc梯度洗脱,脉冲安培检测,建立了脉冲安培检测-离子色谱法(HPAEC-PAD)测定乳粉中的皮革水解蛋白。结果表明,L-羟脯氨酸在0.05～0.20mg/L内线性良好,线性相关系数r2为0.999,阴性样品加标回收率为92.8%～101.7%,检出限(LOD)为0.015mg/L,定量限(LOQ)为0.050mg/L。相较国家标准方法准确、快速、简便,可以大致反映乳粉中皮革水解蛋白的添加量。

L-hydroxyproline is a characteristic amino acid of the leather hydrolyzed protein.In this paper,samples were hydrolyzed by microwave to make amino acids free.The hydrolysate was purified and filtered with a C 18 column and a 0.22μm hydrophilic filter membrane.An Amino PacTM PA10 anion exchange column was used as the separation column.Gradient elution of NaOH/NaOAc/HOAc was used.The results showed that the linearity of L-hydroxyproline was good in the range of 0.05-0.20 mg/L,and the linear correlation coefficient was 0.999.The recoveries of negative samples were within 92.8%-101.7%.The detection limit(LOD)was 0.015 mg/L,and the quantitative limit(LOQ)was 0.050 mg/L.Compared with the national standard method,this method is accurate,fast,simple,can roughly reflect the amount of leather hydrolyzed protein added in milk powders.