Mass spectrometer

By applying multiple stages of voltage to the conversion dynode in the mass analysis device and calculating the optimal voltage, the problem of reduced sensitivity and noise in high mass-to-charge ratio ion detection is solved, and the signal-to-noise ratio and analysis accuracy are improved.

Inactive Publication Date: 2015-05-20
SHIMADZU SEISAKUSHO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For example, as disclosed in Patent Document 2, when there is a possibility that the detector is saturated due to an excessive amount of ions, the gain can be lowered by lowering the CD voltage, but basically the CD voltage is kept constant.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0061] An embodiment of the mass spectrometer according to the present invention will be described in detail with reference to the drawings. figure 1 It is the overall structural diagram of the liquid chromatography mass spectrometry device (LC / MS) of the present embodiment, figure 2 yes figure 1 The block diagram of the ion detector in .

[0062] The LC / MS in this example includes an LC (liquid chromatography) section 1 and an MS (mass spectrometry) section 2 . In the LC unit 1 , the mobile phase stored in the mobile phase container 10 is sent to a column 13 at a substantially constant flow rate by a liquid delivery pump 11 . When a certain amount of sample liquid is injected through the injector (injector) 12, the sample liquid is sent into the chromatographic column 13 along with the flow of the mobile phase. The components are separated in the time direction and stripped from the chromatographic column 13 outlet.

[0063] The MS unit 2 has a structure of a multi-stage...

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PUM

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Abstract

CD voltage applied to a conversion dynode for an ion detector (29) is switched each time a target sample is injected by an injector (12) in an LC unit (1) and mass spectrometry is executed for a target component in the sample. A data acquisition unit (32) acquires noise data during a period in which the component is not present and intensity data for ions originating in the target component for each CD voltage in a plurality of steps, and an SN ratio calculation unit (33) calculates an SN ratio. After execution is completed, an optimal CD voltage determination unit (34) compares the SN ratios for each CD voltage and stores a CD voltage that gives the maximum SN ratio in an optimal CD voltage storage unit (42) as the optimal CD voltage for m / z for the analytic conditions and target of analysis in that instance. Thus, even when the mobile phase flow rate is particularly high or a mobile phase that does not easily volatilize is used, a detection signal with an excellent SN ratio for which the optimal CD voltage is set can be obtained.

Description

technical field [0001] The present invention relates to a mass spectrometer, and more specifically, to a mass spectrometer using an ion detector combining a conversion dynode and a secondary electron multiplier. Background technique [0002] In a mass spectrometer, a secondary electron multiplier tube is often used as a detector for detecting ions (see Patent Document 1). The secondary electron multiplier tube has a multistage structure of dynodes (dynodes), and repeatedly multiplies secondary electrons released from primary dynodes by ion injection. Then, the increased secondary electrons are injected into the collector and converted into a current signal, which is extracted as a detection signal. [0003] In order to apply ion acceleration voltages to the dynodes of each stage, a fixed detection voltage is usually applied to the secondary electron multiplier tube. However, even if the detection voltage is fixed, the detection sensitivity of the secondary electron multipl...

Claims

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Application Information

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Patent Type & AuthorityApplications(China)
IPC IPC(8): H01J49/06G01N27/62H01J43/10
CPCH01J49/025H01J49/0027G01N30/7233H01J49/0431H01J49/10
OwnerSHIMADZU SEISAKUSHO LTD