液相色谱-串联质谱法测定牛乳基婴幼儿配方奶粉中的乳铁蛋白

Determination of lactoferrin in milk-based infant formula by liquid chromatography-tandem mass spectrometry

中文关键词:  牛乳基婴幼儿配方奶粉  液相色谱-串联质谱法  乳铁蛋白  特征肽段

英文关键词:milk-based infant formula  liquid chromatography-tandem mass spectrometry  lactoferrin  signature peptide

中文摘要:

      目的 建立液相色谱-串联质谱法(liquid chromatography-tandem mass spectrometry, LC-MS/MS)测定牛乳基婴幼儿配方奶粉中的乳铁蛋白含量的分析方法。方法 试样中的乳铁蛋白经尿素-碳酸氢铵缓冲液提取, 二硫苏糖醇还原, 碘乙酰胺烷基化, 37 ℃酶解后, 特征肽段用液相色谱-串联质谱正离子模式测定, 内标法定量。结果 乳铁蛋白在0.00080~0.16000 pmol/μL(相当于10~2000 mg/100 g)水平间线性关系良好, 相关系数r=0.9997, 定量限为0.0020 pmol/μL(相当于25 mg/100 g), 加标回收率为89.71%~106.28%, 相对标准偏差为2.96%~4.15%。结论 该方法准确度好、特异性强、灵敏度高, 可用于牛乳基婴幼儿配方奶粉中的乳铁蛋白含量的测定。

英文摘要:

      Objective To establish a method for the determination of lactoferrin in milk-based infant formula by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Methods Lactoferrin was extracted by urea-ammonium bicarbonate buffer, reduced with dithiothreitol, alkylated with iodoacetamide, digested at 37 ℃. Afterwards, the lactoferrin was quantified using the derived signature peptides using liquid chromatography-tandem mass spectrometry in positive ion mode with correction of isotope-labelling internal standard. Results The method showed a good linearity between 0.00080?0.16000 pmol/μL (correspond to 10-2000 mg/100 g) with the correlation coefficient r=0.9997. The limit of quantitation for the method was 0.0020 pmol/μL, which was equivalent to 25 mg/100 g. The recoveries ranged from 89.71% to 106.28%, and relative standard deviations varied from 2.96%?4.15%. Conclusion The proposed method has good accuracy and specificity, as well as high sensitivity, which can be used for the determination of lactoferrin in milk-based infant formula.