Triple quadrupole mass analyzer

Abstract

Each element is configured such that the linear ion optical axis (C1) of the ion source (11), the first ion lens (12), and the front-stage quadrupole mass filter (13) are in contact with the ions in the collision unit (14) The linear ion beam axis (C2) of the guide (15) and the rear-stage quadrupole mass filter (18) obliquely intersects at a predetermined angle in the space between the front-stage quadrupole mass filter and the collision cell. The metastable He molecules (He*) generated by the ion source cannot reach the exit of the collision cell and are removed even if they pass through the front-stage quadrupole mass filter. On the other hand, the precursor ions passing through the front-stage quadrupole mass filter are bent along the zigzag ion optical axis under the action of the DC electric field formed by the ion lens (16) on the entrance side, and are efficiently introduced into the collision cell . He*, which causes noise, can be reliably removed without using an ion optical element with a special shape or structure.

Description

technical field [0001] The present invention relates to a triple quadrupole type that splits ions with a specific mass-to-charge ratio m / z by collision-induced dissociation (CID=Collision-Induced Dissociation), and performs mass analysis on the resulting product ions (fragment ions) A mass analysis device, in particular, relates to a triple quadrupole mass analysis device suitable for a detector of a gas chromatograph. Background technique [0002] A method called MS / MS analysis (also called tandem analysis) is known as a method of mass analysis for identification of a substance with a large molecular weight and analysis of its structure. As a typical MS / MS type mass spectrometer, there is a triple quadrupole type mass spectrometer. [0003] image 3 It is a schematic configuration diagram of a common triple quadrupole mass spectrometer. The triple quadrupole mass spectrometer includes quadrupole mass filters 13 and 18 for separating ions according to the mass-to-charge ra...

AI Technical Summary

Problems solved by technology

[0009] However, there are problems in the previous methods as mentioned above

That is, ion guides for transporting ions are generally composed of quadrupole or higher multipole rods, but if it is desired to assemble curved multipole rods while maintaining high dimensional accuracy, the cost is considerably high

In addition, if sufficient mechanical precision cannot be secured, the efficiency of passage of ions to be analyzed decreases, resulting in a decrease in sensitivity

[0010] On the other hand, when making He* and N 2 In the method of removing them by contacting them with a gas, etc., the ions themselves of the analysis target also pass through the same gas region, so the passing efficiency of the ions is still reduced, and the signal level in the detector is reduced, so even if the noise is reduced, it does not necessarily Can improve S / N

In addition, there is the following problem: In order to change He* into He, it is necessary to form N 2 In the gas area, in order to maintain a high vacuum in the vacuum chamber, it is necessary to increase the vacuum exhaust capability

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