GB/T 223.89-2019 English PDF (GB/T223.89-2019)

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GB/T 223.89-2019: Iron, steel and alloy -- Determination of tellurium content -- Hydride generation-atomic fluorescence spectrometric method
GB/T 223.89-2019
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.080.01
H 11
Iron, steel and alloy - Determination of tellurium
content - Hydride generation-atomic fluorescence
spectrometric method
ISSUED ON: AUGUST 30, 2019
IMPLEMENTED ON: JULY 01, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Principle ... 5
4 Reagents ... 5
5 Instruments ... 6
6 Sample taking and preparation ... 7
7 Analysis steps ... 7
8 Result calculation ... 10
9 Precision ... 11
10 Test report... 11
Annex A (informative) Precision test related information ... 13
Iron, steel and alloy - Determination of tellurium
content - Hydride generation-atomic fluorescence
spectrometric method
CAUTION - The personnel using this Part shall have hands-on experience
in formal laboratory work. This Part does not address all possible safety
issues. It is the responsibility of users to take appropriate safety and
health measures and to ensure compliance with the conditions set by the
relevant national regulations.
1 Scope
This Part of GB/T 223 specifies a method for the determination of tellurium
content by hydride generation-atomic fluorescence spectrometric method.
This Part applies to the determination of tellurium content in iron, steel and alloy.
The determination range is 0.00001 % ~ 0.005 % of mass fraction.
2 Normative references
The following referenced documents are indispensable for the application of
this document. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any
amendments) applies.
GB/T 6379.1 Accuracy (trueness and precision) of measurement methods
and results - Part 1: General principles and definitions
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 6682 Water for analytical laboratory use - Specification and test
methods
GB/T 20066 Steel and iron - Sampling and preparation of samples for the
determination of chemical composition
WEIGH 10 g of potassium borohydride; DISSOLVE in potassium hydroxide
solution (5 g/L) and DILUTE to 500 mL. Prepare before use.
4.12 Tellurium standard solution
4.12.1 Tellurium standard stock solution, 100 μg/mL
WEIGH 0.1000 g of pure tellurium (the mass fraction of tellurium is not less than
99.99 %); PLACE in a 150 mL beaker; ADD 10 mL of nitric acid (see 4.6);
COVER the surface dish; HEAT to complete dissolution at low temperature;
TRANSFER to a 1000 mL volumetric flask; DILUTE to the mark with water; MIX
well.
1 mL of this solution contains 100 μg of tellurium.
4.12.2 Tellurium standard solution A, 10.0 μg/mL
PIPETTE 10.0 mL of tellurium standard stock solution (see 4.12.1); PLACE in
a 100 mL volumetric flask; DILUTE to the mark with hydrochloric acid (1+9);
MIX well.
1 mL of this solution contains 10.0 μg of tellurium.
4.12.3 Tellurium standard solution B, 1.0 μg/mL
PIPETTE 10.0 mL of tellurium standard solution A (see 4.12.2); PLACE in a 100
mL volumetric flask; DILUTE to the mark with hydrochloric acid (1+9); MIX well.
1 mL of this solution contains 1.0 μg of tellurium.
4.12.4 Tellurium standard solution C, 0.10 μg/mL, prepare before use
PIPETTE 10.0 mL of tellurium standard solution B (see 4.12.3); PLACE in a
100 mL volumetric flask; DILUTE to the mark with hydrochloric acid (1+9); MIX
well.
1 mL of this solution contains 0.10 μg of tellurium.
5 Instruments
Non-dispersive atomic fluorescence spectrometer, fitted with hydride generator
and special tellurium hollow cathode lamp.
After optimization, the non-dispersive atomic fluorescence spectrometer used
shall achieve the following indicators:
a) Short-term precision: Measure the fluorescence intensity of the tellurium
5 %, precipitate will occur at the bottom of the beaker. The precipitate may be crushed with a
glass rod and then ammonium fluoride solution (see 4.9) is added.
Table 2 -- Acid used to dissolve different types of samples
Sample type Amount of hydrochloric acid and nitric acid used
Medium and low alloy steels of which the
mass fraction of pure iron, pure nickel and
chromium is less than 5 %
Add 5 mL of nitric acid (see 4.6) to decompose the sample,
and then add 7.5 mL of hydrochloric acid (see 4.3)
Stainless steel 10 mL of hydrochloric acid, nitric acid mixed acid (see 4.7)
Superalloy 10 mL of hydrochloric acid, nitric acid mixed acid (see 4.8)
7.3.2 Treatment of test solution
7.3.2.1 Mass fraction of tellurium is not greater than 0.0005 %
TRANSFER the test solution (see 7.3.1) to a 50 mL volumetric flask; ADD 15
mL of hydrochloric acid (see 4.3) and 15 mL of citric acid solution (see 4.10);
COOL to room temperature; DILUTE to the mark with water; MIX well; PLACE
for 40 min for determination.
7.3.2.2 Mass fraction of tellurium is greater than 0.0005 %
TRANSFER the test solution (see 7.3.1) to a 50 mL volumetric flask; DILUTE
to the mark with water; MIX well. PIPETTE 5.0 mL of test solution; PLACE in a
50 mL volumetric flask; ADD 24 mL of hydrochloric acid (see 4.3), 2.5 mL of
ammonium fluoride solution (see 4.9), 15 mL of citric acid solution (see 4.10);
COOL to room temperature; DILUTE with water to the mark; MIX well; PLACE
for 40 min for determination.
7.3.3 Measurement of atomic fluorescence intensity
START UP; SET the lamp current and negative high voltage; PREHEAT at least
20 min before measurement; OPTIMIZE the instrument according to the
instrument specifications.
PREPARE potassium borohydride solution (see 4.12) and test solution (see
7.3.2.1 or see 7.3.2.2); USE hydrochloric acid (see 4.4) as the carrier;
MEASURE the atomic fluorescence intensity of tellurium in the test solution
according to the set procedure.
The atomic fluorescence intensity of tellurium in the test solution minus the
atomic fluorescence intensity of tellurium in the blank solution of the sample is
the net atomic fluorescence intensity.
7.4 Plotting of calibration curve
7.4.1 Mass fraction of tellurium is not greater than 0.0005 %
micrograms per milliliter (μg/mL);
f - the diluting factor;
V - the volume of the test solution to be tested, in milliliters (mL);
m - the value of the sample mass, in grams (g).
The analysis results retain 2 significant figures.
9 Precision
The precision of this Part is determined by a joint test of 9 levels of tellurium in
11 laboratories. Each level is tested twice in each laboratory under the
repeatability conditions specified in GB/T 6379.1.
The samples used and the precision test results are listed in Annex A.
The test results reported by each laboratory are statistically analyzed according
to GB/T 6379.2. The correlation between the obtained tellurium content and the
repeatability limit r and the reproducibility limit R is shown in Table 5.
Table 5 -- Repeatability and reproducibility of tellurium
Element Range/% Repeatability limit r Reproducibility limit R
Tellurium 0.00001 ~ 0.005
m in the formulas is the average value of the two measured values, expressed
in % (mass fraction).
The repeatability limit r and the reproducibility limit R are obtained according to
the formulas given ...