Analysis method of quadrupole rod mass analyzer

Abstract

The invention belongs to the mass analysis field, and relates to an analysis method of a quadrupole rod mass analyzer. The analysis method of a quadrupole rod mass analyzer uses the working voltage technology loaded on a quadrupole rod to realize a higher quadrupole mass spectrum mass distinguishing capability, that is, two AC excitation voltages are applied to the quadrupole rod, except for a DC (Direct Current) voltage and an RF (Radio Frequency) voltage on a traditional quadrupole rod, so that an unstable band is generated at the top point of a stable area correspondingly. Therefore, the peak form is effectively optimized and the reliability of mass distinguishing and measurement can be improved. As the stable band is scanned according to the analysis method of a quadrupole rod mass analyzer, the mass distinguishing of the quadrupole rod can exceed 10000 and has no substantial ion transmission loss.

Description

technical field [0001] The invention belongs to the technical field of mass analysis, and in particular relates to an analysis method of a quadrupole mass analyzer, which realizes higher quadrupole mass spectrum mass resolution capability by using a new working voltage loaded on the quadrupole rod. Background technique [0002] Using a quadrupole electrode system to construct a quadrupole mass analyzer is a very mature technology invented by Paul et al. in the middle of the last century. For example, in the U.S. Patent U.S. Pat. Four electrode rods fixed on a central axis, and two symmetrical electrode rods are connected together, the output will be: [0003] [0004] A radio frequency (RF) voltage is connected to a pair of electrodes, and the output will be: [0005] [0006] The radio frequency (RF) voltage is connected to the other pair of electrodes, here stands for DC voltage, stands for AC voltage, is the angular frequency of the RF power supply. [0007]...

AI Technical Summary

Problems solved by technology

The second method is to reduce the radial velocity of the ion beam, however, since many ions have an energy spread of several eV, it becomes difficult to reduce the radial velocity of the ion beam below 10 eV

The third method needs to increase the RF frequency to increase the ion movement cycle

This method also has limitations in practical applications

According to equation (2), increasing the RF frequency by a factor of 2 requires increasing the RF voltage by a factor of 4, so as to ensure that ions of the same mass number are located at the apex of the stable region, so the mass range will be limited by the maximum voltage

Furthermore, even though the ion travel time in the quadrupole is increased, the ion travel time in the higher order fields is also increased

At the ends of the quadrupole, the electric field is very different from that in equation (1), leading to beam dispersion and loss of ion transmission

In summary, it is difficult to find a way to improve mass resolution without sacrificing ion transmission efficiency

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