Department of Chemistry, Washington State University, Pullman, Washington, 99164, USA.
J Mass Spectrom. 2020 Dec;55(12):e4661. doi: 10.1002/jms.4661.
The first completely digital quadrupole mass filter was recently introduced. There is now a need to understand and demonstrate the benefits of digital operation and compare them to the commercial standards. Our work to date has demonstrated that sine and square wave operation are very similar because of their similar stability diagrams and because they use a direct current (DC) potential between the electrode pairs to narrow and limit the mass range. In contrast, rectangular wave-operated digital mass filters and ion traps narrow and limit the stable mass range with the waveform duty cycle without the need for a DC potential. To understand and compare the differences between rectangular and sinusoidal modes of operation, our group has developed new spreadsheet tools that permit calculation of the m/z versus frequency space stability diagrams with the application of a DC potential between the electrode sets for rectangular and sine waveforms, and plots of the pseudopotential well depth against the entire range of stable m/zs for rectangular and sine waveforms. Our spreadsheets were used to make comparisons between fixed-frequency variable-voltage and fixed-voltage variable-frequency modes of operation. They provide a comprehensive companion tool for operating in the laboratory frame and are tunable to the instrument. This manuscript introduces these tools as it compares sine and rectangular wave modes of operation and provides a basis for understanding the advantages and disadvantages of digital operation relative to conventional technology.
最近引入了第一个完全数字化的四极质量滤波器。现在需要了解和展示数字操作的优势，并将其与商业标准进行比较。我们迄今为止的工作表明，由于正弦波和方波操作具有相似的稳定性图，并且它们使用电极对之间的直流（DC）电势来缩小和限制质量范围，因此它们的操作非常相似。相比之下，矩形波操作的数字质量滤波器和离子阱使用波形占空比而无需直流电势来缩小和限制稳定的质量范围。为了理解和比较矩形波和正弦波操作模式之间的差异，我们的小组开发了新的电子表格工具，允许在电极组之间施加直流电势来计算矩形波和正弦波的 m/z 与频率空间稳定性图，以及绘制矩形波和正弦波的整个稳定 m/z 范围的拟位阱深度图。我们的电子表格用于比较固定频率可变电压和固定电压可变频率操作模式。它们为在实验室框架内操作提供了一个全面的配套工具，并可根据仪器进行调整。本文介绍了这些工具，比较了正弦波和矩形波操作模式，并为理解数字操作相对于传统技术的优缺点提供了基础。
