含高阶场成分的四极杆电极系统及其性质

The Quadrupole Rod System with Added Higher Order Fields

由4根柱状电极组成的四极杆电极系统在射频电源的作用下主要产生以四极电场为主的电场分布。四极电场可以用于离子质量分析、离子存储和离子传输等。理论分析表明,只有用4根双曲面电极组成四极杆电极系统时,才会产生纯四极场分布;在其他情况下,除四极电场外,还可能会产生六极、八极、十二极、二十极等高阶电场成分。本研究用数值计算的方法,分析了用4根不同直径的圆柱形电极组成的四极杆电极系统的电场分布情况和作为质量分析器时的性能。结果表明:当用3根相等直径和1根较大直径的圆柱形电极组成四极杆电极系统时,可以产生除四极电场外的高阶电场分布,其高阶场成分主要有六极场(A3)、八极场(A4)、十极场(A5)、十二极场(A6)、二十极电场(A10)等;各种高阶场的含量可以通过改变圆柱形电极的直径,或使具有较大直径的圆柱形电极偏转一定的角度加以调节;当四极电场中含有一定量的高阶电场时,仍可获得较好的质量分辨。含高阶场的四极杆电极系统具有较高的离子传输效率和更好的离子串联质谱分析能力,具有潜在的实用价值。

When supplied with radio-frequency power, quadrupole rodset with four cylindri cal electrodes mainly produces quadrupole electric field. Quadrupole field can be used for the ion mass analysis, ion storage and ion transmission etc. Theoretical analysis shows that the pure quadrupole field can only be produced by four hyperbolic cross sectional electrodes. In other cases, higher order fields will be produced, such as hexapole, octopole, decapole, dodecapole and so on. Electric field distribution and the performance of the quadrupole rod system which were composed of four cylindrical rods with different diameters were investigated with numerical calculation. The results show that some higher order fields, such as A3, A4 , A5, AG, A10 can be added to the quadrupole field when the quadrupole rod system is composed of three identical rods and one bigger rod, and the quantity of each field can beadjusted b The quadr tion. And y changing the diameters of the rods, or rotating the big upole rod system with added higher order fields can sti it could also have higher ion transmission efficiency and trometry analysis ability, the quadrupole rod system given in this practical value. get rod with some angle. 11 has good mass resolu- better tandem mass speepaper will have potential