GB/T 6041-2020 English PDF (GBT6041-2020)

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GB/T 6041-2020: General rules for mass spectrometric analysis
GB/T 6041-2020
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.080.01
G 15
Replacing GB/T 6041-2002
General rules for mass spectrometric analysis
ISSUED ON: MARCH 31, 2020
IMPLEMENTED ON: FEBRUARY 01, 2021
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of
China.
Table of Contents
Foreword ... 3 
1 Scope ... 5 
2 Terms and definitions ... 5 
3 Overview ... 7 
4 Instruments ... 7 
5 Preparation of the instrument ... 15 
6 Qualitative analysis ... 19 
7 Quantitative analysis ... 20 
General rules for mass spectrometric analysis
1 Scope
This Standard specifies the general methods of using mass spectrometers to
perform mass qualitative analysis and quantitative analysis.
This Standard applies to qualitative analysis and quantitative analysis of mass
spectrometry.
2 Terms and definitions
The following terms and definitions are applicable to this document.
2.1 Background
Under the same conditions as the analyzed sample, the mass spectrum signal
that is generated when the sample is not fed.
2.2 Interference
Factors that affect the accuracy of analysis results when analyzing a component
in a mixed sample.
2.3 Mass-to-charge ratio
The ratio of the mass of ion (measured in relative atomic mass units) to the
charge it carries (measured in electron charge); it is abbreviated m/z.
2.4 Mass range
A range between the lower and upper limits of the mass-to-charge ratio that the
mass spectrometer can measure.
2.5 Sensitivity
Under the specified conditions, for a certain mass spectrum peak that is
generated by the selected compound, the response value of the instrument to
the unit sample.
2.6 Resolution
Under the given sample conditions, the separating capacity of the instrument to
two adjacent mass spectrum peaks. For two adjacent mass spectrum peaks of
equal height, when the peak valley is not greater than 10% of the peak height,
The sampler is a device that introduces the sample into the ion source of the
instrument. The sampler is required to introduce the sample into the ion source
without changing the structure and composition of the sample and under the
vacuum state of the mass spectrometer. Commonly used samplers include
diffusion sampling system, direct sampling system and chromatographic
sampling system.
4.2.2 Diffusion sampling system
It is generally composed of sample introduction device, gas storage tank,
sample measurement device, evacuation and heating device, and
corresponding control valves. It is required that the pressure of the storage tank
does not change significantly during the measurement process, so as to obtain
a stable ion flow. This system is mostly suitable for gas, low-boiling liquid or
medium-vapor pressure solid samples without further separation.
4.2.3 Direct sampling system
Commonly used direct sampling method includes probe sampling and injection
sampling.
The probe sampling system is composed of probe rod, heating wire, sample
cup and vacuum locking system. Place the sample in a small cup at the top of
the probe rod; after directly placing the probe into the ion source through the
sample inlet of the mass spectrometer, heat the ion source until the sample
volatilizes. It is mostly used for liquid or solid pure compounds that are hard to
volatile.
For injection sampling, generally introduce the sample solution directly into the
ion source through a syringe or an injection pump in a manual or automatic
manner. It is mostly used for mass spectrometer tuning and solution sample
analysis.
4.2.4 Chromatographic sampling system
For mixture samples of more complex components, it is necessary to use a
chromatograph to separate the sample into single components before it enters
the ion source of the mass spectrometer. For gas chromatography-mass
spectrometry instrument, it generally introduces the analyte from the outlet of
the chromatographic column to the ion source through interfaces such as direct
introduction, open split flow, or jet separator; for liquid chromatography-mass
spectrometry instrument, it mainly uses spraying techniques such as
electrospray, thermo-spray and ion-spray to realize sample injection.
4.3 Ion source
4.3.1 Overview
Atmospheric pressure chemical ionization is commonly used in liquid
chromatography-mass spectrometry instruments. The corona needle
discharges to ionize the solvent; the charged solvent molecules react with the
sample molecules to ionize the molecules, which transfers the charge to the
sample molecules, so as to ionize the sample molecules. Atmospheric pressure
chemical ionization is also a "soft ionization" method, which is suitable for the
analysis of non-polar and moderately polar organic compounds.
4.3.6 Matrix assisted laser desorption ionization (MALDI)
It is the cocrystallization film that is formed when using laser to irradiate the
sample and the matrix. The matrix absorbs energy from the laser and transfers
it to the sample molecules to initiate ionization and desorption of the two; it also
has a charge transfer reaction, which ionizes the sample molecules. This
ionization source can obtain a large number of single-charged ions, which is a
soft ionization technology. The ionization source is widely used in the analysis
of large biological molecules and synthetic polymers.
4.3.7 Inductively coupled plasma (ICP)
The inductively coupled plasma is composed of radio frequency generator, work
coil and working gas. The radio frequency generator passes the high-frequency
current through the work coil to generate a strongly oscillating ring magnetic
field in the direction of the axis of the coil; when argon is introduced into the
torch tube, the high-frequency spark discharge of the igniter ionizes a small
amount of argon in the torch tube; the conductive particles in the torch tube
oscillate with the frequency of the magnetic field under the action of the
magnetic field, which forms a circular current coaxial with the rectangle tube;
atoms, ions, and electrons collide with each other in a strong oscillating motion
to produce more electrons and ions; finally, a stable and continuous argon
plasma is formed at the torch tube mouth, which fully ionize the sample aerosol
that enters the plasma torch flame through the torch tube in a high temperature
and inert atmosphere. This ionization source is mainly used for elemental
analysis.
4.3.8 Surface ionization (STI)
Surface ionization is also called thermal ionization. Its ionization box is usually
equipped with three or two strips of tungsten (or tantalum) which are insulated
from each other. The current passing through each strip can be adjusted
separately and can be changed within the temperature range of 1 800 K ~ 2
700 K. Coat the sample on the tungsten strip on the side and power on to heat.
The center zone temperature is higher than the side zone temperature. Under
the action of thermal energy, a part of the analyzed elements is ionized. This
ionization source is mostly used for isotope analysis.
v -- the flight speed of ions, in meters per second (m/s).
Therefore, the m/z value of the ion can be determined by its time of flight.
4.5.4 Ion trap mass analyzer
4.5.4.1 It is divided into 3D ion trap and linear ion trap. The core components of
different types of ion traps are the electrode systems which are used to
generate the electromagnetic fi...