Pseudo internal standard method, device and application for mass spectrometry quantitative analysis

• US 10,643,829 B2
• Filed: 08/30/2016
• Issued: 05/05/2020
• Est. Priority Date: 09/21/2015
• Status: Active Grant

• Current Assignee: Guangdong Lianjie Biotechnology Co., Ltd.
• Original Assignee: Guangdong Lianjie Biotechnology Co., Ltd.
• Inventors: Zhu, Janshon
• Primary Examiner(s): Stoffa, Wyatt A
• Application Number:
  US15/762,019
• Publication Number:
  US 20180269047A1
• Time in Patent Office: 1,344 Days
• CPC Class Codes: G01N 2030/042 Standards
• CPC Class Codes: G01N 2030/8822 involving blood
• CPC Class Codes: G01N 30/06 Preparation
• CPC Class Codes: G01N 30/20 using a sampling valve
• CPC Class Codes: G01N 30/36 in high pressure liquid systems
• CPC Class Codes: G01N 30/72 Mass spectrometers mass spectrometers per se H01J49/00
• CPC Class Codes: G01N 30/7233 interfaced to liquid or supercritical fluid chromatograph interfaces in general for introducing or extracting samples to be analysed with specially adapted mass spectrometer, see H01J49/04
• CPC Class Codes: G01N 30/86 Signal analysis
• CPC Class Codes: G01N 30/8665 for calibrating the measuring apparatus
• CPC Class Codes: G01N 30/88 Integrated analysis systems specially adapted therefor, not covered by a single one of the groups G01N30/04 - G01N30/86
• CPC Class Codes: H01J 49/0009 Calibration of the apparatus

Abstract

A pseudo internal standard method, device and application for mass spectrometry quantitative analysis is disclosed.

Claims

1. A method of pseudo internal standard for mass spectrometry quantitative analysis, the method comprising:

weighing a standard substance to prepare standard solutions of different concentrations using a blank substrate of a test sample to form a calibration series having a concentration range;

then weighing the same standard substance to prepare internal standard solutions of the different concentrations using the blank substrate of the test sample to form an internal standard series having the concentration range of said calibration series;

processing said standard solutions by a standard sample treatment process to obtain standard samples and processing said internal standard solutions by the sample treatment process to obtain internal standard samples;

analyzing said standard samples one by one on a chromatography-mass spectrometry system by injecting one of said standard samples followed by injecting one of said internal standard samples;

plotting ratios (R) between a peak area of said standard samples (A_std) and a normalized peak area of said internal standard samples (A_is/Cd_is, where A_is, and C_is are the peak area and concentration of said internal standard sample, respectively, wherein R=A_std·

C_is/A_is versus the different concentrations of said standard samples (C_std) to establish a calibration curve and a fitting equation thereof;

processing the test sample by the same sample treatment process then injecting the processed test sample and one of the internal standard samples into the chromatography-mass spectrometry system to perform analysis, wherein after a chromatographic peak of a test sample is detected, estimating the sample concentration and amount based on a previous calibration curve, selecting an internal standard sample with a concentration closest to the estimated one, calculating the volume needed to match the sample amount, then injecting the selected internal standard sample with the calculated volume; and

calculating a test sample concentration by substituting a test sample ratio between a test sample peak area of the test sample and the normalized peak area of the selected internal standard sample into the fitting equation of the calibration curve.

2. The method of claim 1, further comprising:

pausing an injector after each completion of injection of said standard sample—

for a time required for a chromatographic peak to be complete;

wherein said selected internal standard sample goes through a chromatographic column of the chromatography-mass spectrometry system;

wherein said standard sample and said selected internal standard sample are separated and analyzed in a same detection cycle.

3. The method of claim 1, wherein:

said selected internal standard sample is injected after completion of the chromatographic peak of said standard sample or a test sample; and

said selected internal standard sample directly enters the mass spectrometer in a manner of flow injection to perform detection bypassing said chromatographic column of said chromatography-mass spectrometry system.

4. The method of claim 3, wherein when said selected internal standard sample is injected using the flow injection, a flow rate of the flow injection is 20% lower than a flow rate of a mobile phase in the sample analysis, or the flow of spray gas is increased from 60 PSI to 70 to 100 PSI.

5. The method of claim 1, wherein:

after a chromatographic peak of the standard sample is detected, injecting an internal standard sample with a concentration closest to a concentration of said standard sample;

after a chromatographic peak of a test sample is detected, estimating the sample concentration and amount based on a previous calibration curve, selecting an internal standard sample with a concentration closest to the estimated one, calculating the volume needed to match the sample amount, then injecting the selected internal standard sample with the calculated volume.