Borchers C, Parker C E, Deterding L J, Tomer K B
Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
J Chromatogr A. 1999 Aug 27;854(1-2):119-30. doi: 10.1016/s0021-9673(99)00479-3.
Recent mass spectrometry instrumentation developments include the appearance of novel hybrid tandem instrumentation, Q-TOF, consisting of a quadrupole mass analyzer (MS1) and a time-of-flight (TOF) analyzer. The TOF analyzer is not scanned, but collects all fragment ions entering the analyzer at a given time. Thus, the typical precursor scan experiment cannot be performed. Instead, a full MS-MS spectrum can be acquired for each mass passed by MS1. Appropriate data manipulation, i.e. extracted ion current chromatograms, can correlate specific fragment ion formation to the parent ion. Precursor scanning and LC-MS-MS are compared on a Q-TOF instrument for the determination of protein modifications, including acetylation and phosphorylation. Model peptides used for phosphopeptide detection were generated from a mixture of beta-casein. Model acetylated peptides were generated from a mixture of acetylated substance P1-9 and substance P1-11. The results were then applied to a more complex mixture, a digest of HIV-p24. Results indicate that precursor scanning is useful for screening, but that LC-MS-MS has a sensitivity advantage and is less susceptible to suppression effects. LC-MS-MS, therefore, appears to be better for the detection of trace components in complex mixtures.
近期质谱仪器的发展包括新型混合串联仪器Q-TOF的出现，它由四极杆质量分析器（MS1）和飞行时间（TOF）分析器组成。TOF分析器不进行扫描，而是在给定时间收集所有进入分析器的碎片离子。因此，无法进行典型的前体扫描实验。取而代之的是，可以为MS1传递的每个质量获取完整的MS-MS谱图。通过适当的数据处理，即提取离子流色谱图，可以将特定碎片离子的形成与母离子相关联。在Q-TOF仪器上比较了前体扫描和液相色谱-串联质谱（LC-MS-MS）用于蛋白质修饰（包括乙酰化和磷酸化）的测定。用于磷酸肽检测的模型肽由β-酪蛋白混合物生成。模型乙酰化肽由乙酰化P物质1-9和P物质1-11的混合物生成。然后将结果应用于更复杂的混合物，即HIV-p24的酶解产物。结果表明，前体扫描适用于筛选，但LC-MS-MS具有灵敏度优势，且不易受到抑制效应的影响。因此，LC-MS-MS似乎更适合检测复杂混合物中的痕量成分。
