Nestlé Research Center, Nestec Ltd., P.O. Box 44, CH-1000 Lausanne 26, Switzerland.
Anal Chim Acta. 2010 Jul 5;672(1-2):45-9. doi: 10.1016/j.aca.2010.04.030. Epub 2010 Apr 24.
A LC-MS/MS method has been developed for the direct detection of recombinant bovine somatotropin (rbST) in milk and dairy products. The sample preparation protocol is based on a solid phase extraction step followed by precipitation with cold methanol and enzymatic digestion. The analysis is focused on the tryptic N-terminal peptide, specific of the recombinant form of the hormone and the detection is performed by LC-ESI(+)-MS/MS. This method has been validated according to the European Union criteria described in the Directive 2002/657/EC. Acceptable performances, with a decision limit (CCalpha) of 1.24 ng mL(-1) and detection capability (CCbeta) of 1.92 ng mL(-1) were obtained. Calculation of repeatability and intermediate reproducibility of the signal at 100 ng mL(-1) lead to relative standard deviations lower than 20%, showing the robustness of the method. Samples subjected to various industrial processes namely, heating, freezing, defatting, pasteurization and spray-drying were then analysed in order to determine the consequences of these treatments on the stability of the hormone. Results showed that temperature related processes, such as pasteurization and spray-drying induce a loss of the hormone up to 95%.
已建立一种用于直接检测牛奶和乳制品中重组牛生长激素（rbST）的 LC-MS/MS 方法。样品制备方案基于固相萃取步骤，随后用冷甲醇沉淀和酶解。分析集中在激素重组形式特有的胰蛋白酶 N 端肽上，并且通过 LC-ESI(+)-MS/MS 进行检测。该方法根据指令 2002/657/EC 中描述的欧盟标准进行了验证。获得了可接受的性能，决定限（CCalpha）为 1.24ng/mL，检测能力（CCbeta）为 1.92ng/mL。在 100ng/mL 时对信号的重复性和中间重现性进行计算，导致相对标准偏差低于 20%，表明该方法具有稳健性。对经过各种工业处理的样品（例如加热、冷冻、脱脂、巴氏杀菌和喷雾干燥）进行了分析，以确定这些处理对激素稳定性的影响。结果表明，与温度相关的处理，如巴氏杀菌和喷雾干燥，会导致激素损失高达 95%。
