Multiple reaction monitoring-based determination of bovine 伪-lactalbumin in infant formulas and whey protein concentrates by ultra-high performance liquid chromatography-tandem mass spectrometry using tryptic signature peptides and synthetic peptide stan

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• 作者：Jingshun Zhang^a ; ^b ; Shiyun Lai^c ; Yu Zhang^a ; Baifen Huang^b ; Duo Li^a ; ^{duoli@zju.edu.cn} ; Yiping Ren^b ; ^{renyiping@263.net}
• 关键词：伪-Lactalbumin ; Ultra-high performance liquid chromatography&ndash ; tandem mass spectrometry ; Infant formula ; Signature peptide ; Tryptic peptide
• 刊名：Analytica Chimica Acta
• 出版年：2012
• 期刊代码：2_00032670
• 类别：ch
• 出版时间：21 May, 2012
• 卷：727
• 期：Complete
• 页码：47-53
• 文件大小：714 K

摘要

The determination of 伪-lactalbumin in various dairy products attracts wide attention in multidiscipline fields because of its nutritional and biological functions. In the present study, we quantified the bovine 伪-lactalbumin in various infant formulas and whey protein concentrates using ultra-high performance liquid chromatography coupled to tandem mass spectrometer in multiple reaction monitoring mode. Bovine 伪-lactalbumin was quantified by employing the synthetic internal standard based on the molar equivalent relationship among the internal standard, bovine 伪-lactalbumin and their signature peptides. This study especially focused on the recovery rates of the sample preparation procedure and robust quantification of total bovine 伪-lactalbumin in its native and thermally denatured form with a synthetic internal standard KILDKVGINNYWLAHKALCSE. The observed recovery rates of bovine 伪-lactalbumin ranged from 95.8 to 100.6%and the reproducibility was excellent (RSD < 6%) at different spiking levels. The limit of quantitation is 10 mg/100 g for infant formulas and whey protein concentrates. In order to validate the applicability of the method, 21 brands of infant formulas were analyzed. The acquired contents of bovine 伪-lactalbumin were 0.67-1.84 g/100 g in these infant formulas in agreement with their label claimed values. The experiment of heat treatment time showed that the loss of native 伪-lactalbumin enhanced with an increasing intensity of heat treatment. Comparing with Ren's previous method by analysis of only native bovine 伪-lactalbumin, the present method at the peptide level proved to be highly suitable for measuring bovine 伪-lactalbumin in infant formulas and whey protein concentrates, avoiding forgoing the thermally induced denatured 伪-lactalbumin caused by the technological processing.