GB/T 30903-2026Inorganic chemicals for industrial use - Determination of impurity elements - Inductively coupled plasma mass spectrometry (English PDF)

3.1 Plasma

Ionized gas with a degree of ionization greater than 0.1%.

NOTE: It is composed of electrons, ions, atoms and molecules, with the numbers of electrons and ions being roughly equal, and the whole is neutral. [Source: GB/T 14666-2025, 7.1.22]

3.2 Inductively coupled plasma; ICP

The torch flame that is formed by applying high-frequency power to a coil coupled to a plasma torch.

3.3 Sampling cone

A crucial cone-shaped component for the interface between atmospheric pressure plasma and high vacuum mass analyzers.

NOTE: There is a cone-shaped hole of about 1 mm in the center of the sampling cone. Through this cone-shaped hole, ions in the plasma torch enter the first-stage vacuum chamber supported by a mechanical pump.

3.4 Skimmer cone

Another important cone-shaped component for the interface between atmospheric pressure plasma and a high vacuum mass analyzer.

NOTE: The center of the skimmer cone has a cone hole less than 1 mm in diameter, which is concentric with the axis of the sampling cone hole. Ions enter the mass analyzer through this cone hole.

3.5 Auxiliary gas

Argon gas flow that is introduced between the middle tube and the central tube of the torch.

NOTE: The auxiliary gas serves to support the plasma formed at the torch opening, control the position of the plasma flame, and protect the central tube.

3.6 Carry gas

The airflow introduced through the central tube.

NOTE: The role of the carry gas is to transport aerosols into the plasma.

3.7 Cooling gas

During the operation of the inductively coupled plasma mass spectrometer, the gas that provides a central channel for the sample (nebulized gas), participates in the plasma ignition process, forms a stable plasma torch flame, and isolates and protects the torch.

NOTE: The cooling gas is usually argon.

3.8 Interface

A device consisting of a sampling cone, a skimmer cone, etc., allows ions formed by plasma to enter the channel of a mass separator.

3.9 Mass spectral interference

Interference caused by one or more atomic ions having a similar mass-to-charge ratio to the analyte ions.

3.10 Polyatomic ion interference

Interference caused by complex ions composed of two or more atoms having a similar mass-to-charge ratio to the analyte ions.

7.1 Sample preparation

7.1.1 Dissolution method

For samples of easily soluble inorganic chemical products, weigh an appropriate amount of the specimen, add a certain amount of solvent (usually water or dilute acid) to dissolve it, so that the component to be tested is converted into a measurable form, and then dilute it to a certain volume of test solution for the determination of the content of the component to be tested.

7.1.2 Fusion method

For samples of insoluble inorganic chemical products, weigh an appropriate amount of the specimen, place it in a crucible, add 5~20 times the amount of alkali metal flux (such as lithium metaborate, lithium tetraborate, sodium carbonate, sodium hydroxide, sodium peroxide, corresponding potassium salts and alkali metal fluorides), and mix.

Then, heat and melt the mixture in a high-temperature furnace, generally at a temperature of 500 °C~1200 °C. Then, leach the mixture with water or acid to convert the component to be tested into a measurable form and dilute it to a certain volume of test solution for determining the content of the component to be tested.

7.1.3 Wet digestion method

Weigh an appropriate amount of inorganic chemical product specimen, add a certain amount of a mixture of different acids or mixed acids with hydrogen peroxide or other oxidants, heat and digest to convert the component to be tested into a measurable form, and dilute it to a certain volume of test solution for the determination of the content of the component to be tested.

Commonly used digestion reagents for wet digestion include HNO3, HNO3-HClO4, HNO3-H2SO4, H2SO4-KMnO4, H2SO4-H2O2, HNO3-H2SO4-HClO4, HNO3-H2SO4- V2O5, etc.

Wet digestion methods include open container digestion, sealed high-pressure digestion, and microwave digestion, as detailed below.

a) Open container digestion method. The specimen and digestion reagent are added to an open container and heated for digestion.

b) Sealed high-pressure digestion method. The specimen and digestion reagent are placed in a suitable container and digested under high temperature and high pressure.

c) Microwave digestion method. The specimen and digestion reagent are placed in a sealed container and digested using microwaves.

7.1.4 Separation and preconcentration methods

Inorganic chemical product samples are separated using methods such as solvent extraction, ion exchange, and coprecipitation/adsorption to remove potential matrix effects and interferences, achieve preconcentration, and lower the limit of quantitation.

7.2 Test solution requirements

After processing, samples of inorganic chemical products are diluted to a certain volume based on the content of the analyte and made into test solutions.

The sample weight is determined based on the mass concentration of the analyte in the specimen and the detection limit of the method; the mass concentration of the analyte in the test solution shall be at least three times the detection limit of that element. The method for determining the detection limit is given in Appendix B.

The test solutions used for measurements on the inductively coupled plasma mass spectrometer (ICP-MS) shall meet the following basic requirements.

a) The total dissolved solids (TDS) in the test solution are not greater than 0.2%.

b) The organic content in the test solution shall not be too high. Organic matter can cause severe matrix effects, and carbon particle deposition after organic […]