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GB/T 223.87-2018 (GB/T223.87-2018)

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GB/T 223.87-2018: PDF in English (GBT 223.87-2018)

GB/T 223.87-2018
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.080.01
H 11
Iron, Steel and Alloy - Determination of Calcium and
Magnesium - Inductively Coupled Plasma Mass
Spectrometric Method
ISSUED ON. MAY 14, 2018
IMPLEMENTED ON. FEBRUARY 1, 2019
Issued by. State Administration for Market Regulation of the People’s
Republic of China;
Standardization Administration Committee of the People’s
Republic of China.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative References ... 4 
3 Principle ... 4 
4 Reagents ... 5 
5 Instruments and Equipment ... 7 
6 Sampling and Sample Preparation ... 8 
7 Experimental Procedures ... 8 
8 Result Calculation ... 11 
9 Precision ... 11 
10 Test Report ... 12 
Appendix A (informative appendix)... 13 
Appendix B (informative appendix) ... 14 
Iron, Steel and Alloy - Determination of Calcium and
Magnesium - Inductively Coupled Plasma Mass
Spectrometric Method
1 Scope
This Part in GB/T 223 specifies methods of determining calcium and magnesium
content through inductively coupled plasma mass spectrometric method.
This Part is applicable to the determination of calcium (mass fraction. 0.0002% ~
0.0035%) and magnesium (mass fraction. 0.0003% ~ 0.05%) in iron, steel and alloy.
2 Normative References
The following documents are indispensable to the application of this Standard. In terms
of references with a specified date, only versions with a specified date are applicable
to this Standard. The latest version (including all the modifications) of references
without a specified date is also applicable to this Standard.
GB/T 6379.1 Accuracy (Trueness and Precision) of Measurement Methods and
Results - Part 1. General Principles and Definitions (GB/T 6379.1-2004, ISO 5725-
1.1994, IDT)
GB/T 6379.2 Accuracy (Trueness and Precision) of Measurement Methods and
Results - Part 2. Basic Method for the Determination of Repeatability and
Reproducibility of a Standard Measurement Method (GB/T 6379.2-2004, ISO
5725-2.1994, IDT)
GB/T 6682 Water for Analytical Laboratory Use - Specification and Test Methods
(GB/T 6682-2008, ISO 3696. 1987, MOD)
GB/T 12806 Laboratory Glassware - One-mark Volumetric Flasks (GB/T 12806-
2011, ISO 1042.1998, NEQ)
GB/T 12808 Laboratory Glassware - One-mark Pipettes
GB/T 20066 Steel and Iron - Sampling and Preparation of Samples for the
Determination of Chemical Composition (GB/T 20066-2006, ISO 14284.1996, IDT)
3 Principle
Dissolve reagent in the mixed acid of hydrochloric acid, nitric acid and hydrofluoric acid.
If necessary, adopt perchloric acid to generate fumes. After dilution, import the sample
solution into inductively coupled plasma mass spectrometer with a peristaltic pump.
During the operation of the inductively coupled plasma mass spectrometer, measure
the mass spectrometry signal intensity of the element.
Conduct matrix matching of calibration blank, calibration solution, and main elements
in the sample to be tested, and acid adopted for reagent decomposition. Adopt internal
standard to compensate the instrument’s drifting effect and matrix effect.
4 Reagents
Unless it is otherwise indicated, high-purity reagent (mass fraction of calcium and
magnesium < 0.0001%) or reagent with equivalent purity, and first-grade water
stipulated in GB/T 6682 shall be adopted in analysis. If the requirements cannot be
satisfied, use an acid purification unit (5.3) to purify the reagents.
4.1 Hydrochloric acid,  = 1.19 g/mL.
4.2 Nitric acid,  = 1.42 g/mL.
4.3 Hydrofluoric acid,  = 1.19 g/mL.
4.4 Perchloric acid,  = 1.67 g/mL.
4.5 Calcium standard stock solution, 1,000 μg/mL.
Weigh-take 2.4972 g of calcium carbonate (mass fraction ≥ 99.99%) that is already
dried at 110 °C for 1 h and cooled down to room temperature in a dryer. Place it in 400
mL beaker; add 100 mL of hydrochloric acid (1+1) to dissolve it. After cooling it down,
transfer it into 1,000 mL volumetric flask. Use water to dilute to the constant volume;
thoroughly mix it.
1 mL of this solution contains 1,000 μg of calcium.
4.6 Magnesium standard stock solution, 1,000 μg/mL.
Weigh-take 1.6582 g of magnesium oxide (mass fraction ≥ 99.99%) that is already
burnt at 850 °C for 30 min and cooled down to room temperature in a dryer. Place it in
400 mL beaker; add 100 mL of hydrochloric acid (1+1). After heating it up and
dissolving it, cool it down to room temperature; transfer it into 1,000 mL volumetric flask.
Use water to dilute to the constant volume; thoroughly mix it.
1 mL of this solution contains 1,000 μg of magnesium.
4.7 Mixed standard solution of calcium and magnesium
4.7.1 Mixed standard solution of calcium and magnesium, 100 μg/mL.
7.2 Blank Test
Conduct blank test in accordance with the sample.
7.3 Determination
7.3.1 Preparation of sample solution
In terms of carbon steel and low-alloy steel sample. place the sample (7.1) in 100 mL
quartz beaker. Add 10 mL of water and 5 mL of nitric acid (4.2) [add 0.5 mL of
hydrofluoric acid (4.3) to high-silicon sample], heat it up till it boils. After eliminating
nitrogen oxide, take it down; cool it down, then, transfer it into 100 mL plastic volumetric
flask; add 1.0 mL of internal standard solution of scandium (4.8.3). Use water to dilute
to the constant volume, then, thoroughly mix it for later determination.
In terms of high-carbon steel and alloy steel sample. place the sample (7.1) in 100 mL
quartz beaker. Add 3 mL of hydrochloric acid (4.1) and 1 mL of HNO3 (4.2); use heating
plate to heat it up till it boils. Add 2 mL of perchloric acid (4.4), heat it up till it begins to
fume and stable perchloric acid fume reflux is formed around the bottle mouth or on
the wall. Continue to heat it up, till white perchloric acid fume vanishes. Cool it down,
then, add 3 mL of hydrochloric acid (4.1) and 1 mL of HNO3 (4.2); conduct low-
temperature heating till salt is dissolved. If there are hydrolysable elements in alloy
steel, add 0.5 mL of hydrofluoric acid (4.3) for complexation. Cool it down, then,
transfer to 100 mL plastic volumetric flask; add 1.0 mL of internal standard solution of
scandium (4.8.3). Use water to dilute to the constant volume, then, thoroughly mix it
for later determination.
NOTE. microwave digestion system can also be adopted for the preparation of sample
solution, but the laboratory shall determine an optimized experimental plan in
accordance with conditional experiments.
7.3.2 Preparation of calibration solution
Respectively transfer 0, 0.20 mL, 0.50 mL, 1.00 mL, 2.00 mL and 5.00 mL of mixed
standard solution of calcium and magnesium (4.7.3), and 1.00 mL, 2.00 mL and 5.00
mL of mixed standard solution of calcium and magnesium (4.7.2) in 9 plastic volumetric
flasks (100 mL). Respectively add 10 mL of Fe matrix solution (4.11) and 1.00 mL of
scandium internal standard solution (4.8.3). Add acid that is consistent with sample
dissolution; use water to dilute to the constant volume, then, thoroughly mix it. Solution
that does not contain the mixed standard solution of calcium and magnesium is
calibration blank solution.
7.3.3 Preparation of instrument
Before analysis, ignite plasma; pre-heat it for 30 min ~ 60 min in accordance with the
requirements in the instruction for use to stabilize the instrument. During this process,
pump in water or mass spectrometer cleaning solution (4.10) to rinse nebulizer and
......
 
(Above excerpt was released on 2018-09-01, modified on 2022-02-20, translated/reviewed by: Wayne Zheng et al.)
Source: https://www.chinesestandard.net/PDF.aspx/GBT223.87-2018