Yang Wang, Liqing Wu, Fei Duan, Bin Yang, Yi Yang, Jing Wang
College of Science, Beijing University of Chemical Technology , Beijing, 100029, People's Republic of China.
Division of Medical and Biological Measurement, National Institute of Metrology , Beijing, People's Republic of China.
J Agric Food Chem. 2014 Apr 9;62(14):3073-3080. doi: 10.1021/jf4054337. Epub 2014 Mar 31.
β-Lactoglobulin (β-LG) is one of the major allergenic proteins in milk. There is an urgent demand for an accurate and traceable method to develop β-LG certified reference material (CRM). In this work, β-LG was enzymatically digested and a specific peptide was chosen for quantitation by isotope-dilution mass spectrometry (IDMS). With amino acid CRMs as standards, the results could be traced to SI unit. By the proposed method, the recovery ranged from 86.0% to 118.3% with CVs <9.0%. The LOD and LOQ were 4.8 × 10 g/g and 1.6 × 10 g/g of β-LG in milk powder, respectively. Ten samples from domestic market were analyzed with CVs <5.6%, and the relative expanded uncertainties ranged from 4.2% to 5.9% (k = 2). With the CRMs, it is expected that the comparability of β-LG quantitation results will be improved among different laboratories.
β-乳球蛋白（β-LG）是牛奶中的主要过敏原蛋白之一。迫切需要一种准确且可溯源的方法来制备β-LG认证参考物质（CRM）。在本研究中，对β-LG进行酶解，并选择一种特定肽段通过同位素稀释质谱法（IDMS）进行定量。以氨基酸CRM作为标准物质，结果可溯源至国际单位制（SI）单位。采用所提出的方法，回收率在86.0%至118.3%之间，变异系数（CVs）<9.0%。奶粉中β-LG的检测限（LOD）和定量限（LOQ）分别为4.8×10 g/g和1.6×10 g/g。对来自国内市场的10个样品进行分析，CVs<5.6%，相对扩展不确定度范围为4.2%至5.9%（k = 2）。借助CRM，有望提高不同实验室之间β-LG定量结果的可比性。
