University of Washington, Department of Chemistry, Box 351700, Seattle, Washington 98195-1700, USA.
Anal Chem. 2012 Aug 21;84(16):7124-30. doi: 10.1021/ac3014498. Epub 2012 Aug 10.
One difficulty in using ion mobility (IM) mass spectrometry (MS) to improve the specificity of peptide ion assignments is that IM separations are performed using a range of pressures, gas compositions, temperatures, and modes of separation, which makes it challenging to rapidly extract accurate shape parameters. We report collision cross section values (Ω) in both He and N(2) gases for 113 peptide ions determined directly from drift times measured in a low-pressure, ambient temperature drift cell with radio-frequency (rf) ion confinement. These peptide ions have masses ranging from 231 to 2969 Da, Ω(He) of 89-616 Å(2), and Ω(N(2)) of 151-801 Å(2); thus, they are ideal for calibrating results from proteomics experiments. These results were used to quantify the errors associated with traveling-wave Ω measurements of peptide ions and the errors concomitant with using drift times measured in N(2) gas to estimate Ω(He). More broadly, these results enable the rapid and accurate determination of calibrated Ω for peptide ions, which could be used as an additional parameter to increase the specificity of assignments in proteomics experiments.
使用离子淌度（IM）质谱（MS）提高肽离子分配特异性的一个困难是，IM 分离是在一系列压力、气体组成、温度和分离模式下进行的，这使得快速提取准确的形状参数变得具有挑战性。我们报告了在低压力、环境温度漂移室中直接从测量的漂移时间确定的 113 个肽离子的碰撞截面值（Ω），该漂移室具有射频（rf）离子约束。这些肽离子的质量范围为 231 至 2969 Da，Ω（He）为 89-616 Å（2），Ω（N（2））为 151-801 Å（2）；因此，它们是校准蛋白质组学实验结果的理想选择。这些结果用于量化与肽离子的行波 Ω 测量相关的误差以及在 N（2）气体中测量的漂移时间用于估计 Ω（He）的误差。更广泛地说，这些结果能够快速准确地确定肽离子的校准 Ω，这可以用作增加蛋白质组学实验分配特异性的附加参数。
