Mass Accuracy and Isotopic Abundance Measurements for HR-MS Instrumentation: Capabilities for Non-Targeted Analyses
Mass Accuracy and Isotopic Abundance Measurements for HR-MS Instrumentation: Capabilities for Non-Targeted Analyses
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DOI：
10.1007/s13361-014-0880-5
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发表时间：
2014-07-01
影响因子：
3.2
通讯作者：
Croley, Timothy R.
中科院分区：
文献类型：
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作者：
Knolhoff, Ann M.;Callahan, John H.;Croley, Timothy R.
在许多研究和诊断领域中，开发用于小分子分析的自动化无目标工作流是非常可取的。足够的质量和层析分辨率对于化合物的可探测性以及随后的离子组份和解释是必要的。质量准确度和相对同位素丰度是正确生成未知化合物分子式的关键。虽然高分辨率仪器提供了准确的海量信息，但样品的复杂性会极大地影响数据质量和感兴趣化合物的测量。对两台高分辨率仪器Orbitrap和Q-TOF在四个复杂样品基质中不同浓度的标准混合物的质量准确度和相对同位素丰度进行了评价。Orbitrap和Q-TOF质量精度的总体平均+/-标准偏差分别为1.06+/-0.76ppm和1.62+/-1.88ppm；然而，单独测量的Orbitrap和Q-TOF分别为+/-5ppm和大于10ppm。如果Orbitrap的单同位素峰强度大于1E7，Q-TOF大于1E5，则A+1的相对同位素丰度测量不到理论值的5%，其中误差随强度的降低而增加。此外，在数据中发现了会影响自动化数据分析战略的复杂因素，包括干扰可探测性和相对同位素丰度测量的物种洗脱。将讨论这些发现的影响，重点是对这些工具的合理期望、实验工作流程的指导方针、数据分析考虑因素以及非目标分析的软件设计。
The development of automated non-targeted workflows for small molecule analyses is highly desirable in many areas of research and diagnostics. Sufficient mass and chromatographic resolution is necessary for the detectability of compounds and subsequent componentization and interpretation of ions. The mass accuracy and relative isotopic abundance are critical in correct molecular formulae generation for unknown compounds. While high-resolution instrumentation provides accurate mass information, sample complexity can greatly influence data quality and the measurement of compounds of interest. Two high-resolution instruments, an Orbitrap and a Q-TOF, were evaluated for mass accuracy and relative isotopic abundance with various concentrations of a standard mixture in four complex sample matrices. The overall average +/- standard deviation of the mass accuracy was 1.06 +/- 0.76 ppm and 1.62 +/- 1.88 ppm for the Orbitrap and the Q-TOF, respectively; however, individual measurements were +/- 5 ppm for the Orbitrap and greater than 10 ppm for the Q-TOF. Relative isotopic abundance measurements for A + 1 were within 5% of the theoretical value if the intensity of the monoisotopic peak was greater than 1E7 for the Orbitrap and 1E5 for the Q-TOF, where an increase in error is observed with a decrease in intensity. Furthermore, complicating factors were found in the data that would impact automated data analysis strategies, including coeluting species that interfere with detectability and relative isotopic abundance measurements. The implications of these findings will be discussed with an emphasis on reasonable expectations from these instruments, guidelines for experimental workflows, data analysis considerations, and software design for non-targeted analyses.