CN-122025504-A - Quadrupole rod mass analyzer based on nonlinear dynamic change of resolution and application thereof

Abstract

The invention relates to a quadrupole rod quality analyzer based on nonlinear dynamic change of resolution and application thereof, comprising an FPGA, a digital-to-analog converter, a comparator, a chopping differential converter, a power amplifier and a high-voltage converter which are sequentially connected, wherein the output of the high-voltage converter is also connected to the comparator through a feedback attenuation circuit, the FPGA and the digital-to-analog converter are used for setting the output voltage of a radio-frequency power supply and converting and outputting the output voltage, the comparator is used for comparing the preset voltage with the voltage fed back by the radio-frequency high voltage to output error voltage, the chopping differential converter is used for chopping the error voltage and filtering and screening out a fundamental frequency signal, the power amplifier is used for amplifying the power of the fundamental frequency signal, a half-bridge is used for driving a primary coil of the high-voltage converter, and the feedback attenuation circuit is used for attenuating the AM amplitude modulation signal of the high-voltage converter and detecting and feeding back the AM amplitude modulation signal to the comparator for comparison. The invention dynamically optimizes the resolving power of different quality intervals by precisely controlling the nonlinear relation between the radio frequency RF and the direct current DC voltage.

Inventors

• ZHANG HAN
• SONG BIAO
• TAN TAO
• LUO ZHENZHONG
• YU ZHIWEI
• TANG HUAIWU
• ZHOU CHENG
• QU YING

Assignees

• 杭州泽天春来科技股份有限公司

Dates

Publication Date

20260512

Application Date

20251231

Claims (8)

1. 1. The quadrupole rod quality analyzer based on the nonlinear dynamic change of resolution consists of four parallel metal rods, and is characterized by further comprising an FPGA, a digital-to-analog converter, a comparator, a chopper differential converter, a power amplifier and a high-voltage converter which are sequentially connected, wherein the output of the high-voltage converter is further connected to the comparator through a feedback attenuation circuit; The FPGA and the digital-to-analog converter are used for setting the output voltage of the radio frequency power supply and performing conversion output; The comparator is used for carrying out error comparison on the preset voltage and the voltage fed back by the radio frequency high voltage so as to output error voltage; The chopping differential converter is used for chopping the error voltage and filtering to screen out a fundamental frequency signal; The power amplifier is used for amplifying power of the fundamental frequency signal, and a half-bridge is adopted to drive a primary coil of the high-voltage converter; The feedback attenuation circuit is used for attenuating the AM amplitude modulation signal of the high-voltage converter, and detecting and feeding back the AM amplitude modulation signal to the comparator for comparison.
2. 2. The quadrupole rod quality analyzer based on nonlinear dynamic change of resolution according to claim 1, wherein the power amplifiers are plural and connected in parallel with each other.
3. 3. The quadrupole rod mass analyzer based on nonlinear dynamic change of resolution according to claim 1, characterized in that the working method thereof is as follows: And dynamically adjusting the nonlinear change of the ratio of the direct current voltage DC to the radio frequency voltage RF according to the target mass number.
4. 4. A quadrupole mass analyser according to claim 3, wherein the DC voltage DC and the radio frequency voltage RF for each m/z are calculated in real time, and the DC voltage DC and the radio frequency voltage RF are adjusted according to a predetermined nonlinear function to vary the resolution at different m/z.
5. 5. The resolution nonlinear dynamic change based quadrupole mass analyzer of claim 4, wherein the nonlinear function is an exponential, logarithmic, sigmoid curve or polynomial fit function.
6. 6. The four-pole mass analyzer based on nonlinear dynamic change of resolution according to claim 4, wherein the mass numbers are divided into intervals, and different nonlinear functions are used for different mass number intervals.
7. 7. The quadrupole mass analyzer of claim 6, wherein the DC voltage DC and the RF voltage RF variation are exponentially adjusted for mass intervals less than a predetermined mass threshold and wherein the DC voltage DC and the RF voltage RF variation are polynomial fit for mass intervals not less than the predetermined mass threshold.
8. 8. Use of a quadrupole mass analyzer based on resolution nonlinear dynamics according to any of claims 1-7 in ICP-MS.

Description

Quadrupole rod mass analyzer based on nonlinear dynamic change of resolution and application thereof Technical Field The invention belongs to the technical field of mass spectrometry, and particularly relates to a quadrupole rod mass analyzer based on nonlinear dynamic change of resolution and application thereof. Background The quadrupoles consist of four parallel electrodes, and the applied RF and DC voltages form a hyperboloid electric field. The motion of the ions in the electric field follows the Mathieu equation, the stability parameters a and q determine whether they pass, and only ions meeting the stability condition (a/q.apprxeq.0.168 in the stability region) can pass the quadrupole. Resolution R is defined as r=m/Δm, i.e. the ability to distinguish between adjacent quality numbers. In quadrupole rods, the resolution is mainly determined by: U/V ratio, the stability condition directly affecting a/q, the formula is approximate: ; In the traditional linear mode, the ratio of U/V is fixed, and U and V are synchronously increased in proportion during scanning, so that ions with different masses sequentially pass through, and the resolution is constant at the moment. RF frequency ω, high frequency can increase resolution but decrease sensitivity; quadrupole length L longer quadrupoles can improve resolution but with a tradeoff in volume and cost. The traditional quadrupole mass analyzer adopts a linear resolution mode, the U/V ratio is constant, namely, the direct current voltage U and the radio frequency voltage V are regulated through a fixed proportion relation to realize mass screening. This mode has the following drawbacks: (1) In a wide mass range (e.g. m/z=5-250) analysis, it is difficult to combine the high resolution requirement of the low mass region (< 80 amu) with the sensitivity requirement of the high mass region; (2) The linear parameter setting causes excessive resolution difference between adjacent mass numbers, so that isotope ratio measurement errors are caused; (3) The quality discrimination effect is remarkable, and particularly when analyzing samples with severe multi-atomic ion interference (such as biological/environmental samples), continuous and smooth resolution control cannot be realized, so that the quality axis calibration is difficult. Disclosure of Invention Based on the above-mentioned drawbacks and deficiencies of the prior art, it is an object of the present invention to at least solve one or more of the above-mentioned problems of the prior art, in other words, to provide a quadrupole rod mass analyzer based on resolution nonlinear dynamics which meets one or more of the above-mentioned needs, and applications thereof. In order to achieve the aim of the invention, the invention adopts the following technical scheme: The quadrupole rod quality analyzer based on the nonlinear dynamic change of resolution consists of four parallel metal rods, wherein the quadrupole rod is applied with Direct Current (DC) voltage and Radio Frequency (RF) voltage, and the quadrupole rod quality analyzer further comprises an FPGA, a digital-to-analog converter, a comparator, a chopper differential converter, a power amplifier and a high-voltage converter which are sequentially connected, wherein the output of the high-voltage converter is also connected to the comparator through a feedback attenuation circuit; The FPGA and the digital-to-analog converter are used for setting the output voltage of the radio frequency power supply and performing conversion output; The comparator is used for carrying out error comparison on the preset voltage and the voltage fed back by the radio frequency high voltage so as to output error voltage; The chopping differential converter is used for chopping the error voltage and filtering to screen out a fundamental frequency signal; The power amplifier is used for amplifying power of the fundamental frequency signal, and a half-bridge is adopted to drive a primary coil of the high-voltage converter; The feedback attenuation circuit is used for attenuating the AM amplitude modulation signal of the high-voltage converter, and detecting and feeding back the AM amplitude modulation signal to the comparator for comparison. Preferably, the power amplifiers are connected in parallel. As a preferable scheme, the quadrupole mass analyzer based on nonlinear dynamic change of resolution comprises the following working methods: And dynamically adjusting the nonlinear change of the ratio of the direct current voltage DC to the radio frequency voltage RF according to the target mass number. As a preferable scheme, the direct current voltage DC and the radio frequency voltage RF corresponding to each m/z are calculated in real time, and the changes of the direct current voltage DC and the radio frequency voltage RF are adjusted according to a preset nonlinear function so as to change the resolution under different m/z. Preferably, the nonlinear function is an exponential, log