GB/T 42333-2023 PDF English
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Soil and stream sediment - Determination of iodine content - Pressurized ammonia extraction inductively coupled plasma mass spectrometry
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GB/T 42333-2023: PDF in English (GBT 42333-2023) GB/T 42333-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 73.080
CCS D 47
Soil and stream sediment - Determination of iodine content -
Pressurized ammonia extraction inductively coupled plasma
mass spectrometry
ISSUED ON: MARCH 17, 2023
IMPLEMENTED ON: JULY 01, 2023
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 Terms and definitions ... 5
4 Principle ... 5
5 Test conditions ... 5
6 Reagents or materials ... 5
7 Instruments and equipment ... 6
8 Sample ... 7
9 Test steps ... 7
10 Test data processing ... 8
11 Precision ... 9
12 Accuracy ... 9
13 Quality assurance and control ... 9
Appendix A (Informative) Instrument reference working conditions and analysis
element isotopes, internal standard element isotopes, method detection limits, method
quantification limits ... 11
Appendix B (Informative) Inter-laboratory collaborative test data statistical results .. 12
References ... 14
Soil and stream sediment - Determination of iodine content -
Pressurized ammonia extraction inductively coupled plasma
mass spectrometry
Warning – Personnel using this document must have practical experience in
formal laboratory work. This document does not address all possible security
issues. It is the responsibility of the user to take appropriate safety and health
measures and to ensure compliance with the conditions which are set by the
relevant national regulations.
1 Scope
This document describes a method for the determination of iodine content in soil and
stream sediment by pressurized ammonia extraction inductively coupled plasma mass
spectrometry.
This document is applicable to the determination of iodine content in soil and steam
sediment with the method detection limit and measurement range as follows:
-- method detection limit 0.07 μg/g;
-- measurement range 0.23 μg/g ~ 100 μg/g.
2 Normative references
The following documents are referred to in the text in such a way that some or all of
their content constitutes requirements of this document. For dated references, only the
version corresponding to that date is applicable to this document; for undated references,
the latest version (including all amendments) is applicable to this document.
GB/T 6041, General rules for mass spectrometric analysis
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 6379.4, Accuracy (trueness and precision) of measurement methods and
results - Part 4: Basic methods for the determination of the trueness of a standard
measurement method
GB/T 6682, Water for analytical laboratory use - Specification and test methods
GB/T 14505-2010, Method for chemical analysis of rocks and ores - General rules
and regulations
GB/T 14506.1, Methods for chemical analysis of silicate rocks - Part 1:
Determination of hygroscopic water content
GB/T 33087, Ultra pure water for instrumental analysis specification and test
methods
JJF 1159, Calibration specification for quadrupole inductively coupled plasma mass
spectrometers
3 Terms and definitions
No terms and definitions need to be defined in this document.
4 Principle
The sample is heated with dilute ammonia in a sealed sample dissolver to extract iodine.
The sample solution is measured using an inductively coupled plasma mass
spectrometer and qualitatively determined by the iodine isotope 127I. Within a certain
concentration range, the iodine element mass spectrum count value is proportional to
the mass concentration of the iodine element. The iodine content in the sample is
calculated by measuring the iodine element mass spectrum count value.
5 Test conditions
The test conditions such as temperature, humidity, voltage and frequency during
inductively coupled plasma mass spectrometer detection shall comply with the relevant
requirements of GB/T 6041 and JJF 1159.
6 Reagents or materials
Unless otherwise stated, the reagents used in the analysis are analytical reagents, and
the water is grade-1 water specified in GB/T 6682 or high-purity water for instrumental
analysis specified in GB/T 33087.
6.1 Ammonia [ω(NH3) = 25% ~ 28%].
6.2 Ammonia solution (1+9).
6.3 Ammonia solution (1+99).
7.4 Centrifuge: the maximum speed is 10 000 r/min.
7.5 Sealed sample dissolver: stainless steel outer sleeve, polytetrafluoroethylene inner
tank, volume 15 mL.
7.6 Graduated test tube: 10 mL.
8 Sample
8.1 Prepare the sample in accordance with the relevant provisions of 4.1 in GB/T 14505-
2010. The particle size of the sample shall be less than 74 μm.
8.2 After the sample is naturally air-dried at room temperature, place it in a desiccator
for later use.
8.3 Weigh 0.1 g of the sample, accurate to 0.1 mg, which is the test portion.
8.4 Measure the adsorbed water of the sample dried at room temperature according to
the method specified in GB/T 14506.1.
9 Test steps
9.1 Blank test
Carry out duplicate blank tests along with the test portion. The reagents used shall be
taken from the same bottle of reagents and added in equal amounts.
9.2 Verification test
Analyze standard materials of the same type and similar content along with the test
portion.
9.3 Sample decomposition
9.3.1 Place the test portion (8.3) in the polytetrafluoroethylene inner tank of the sealed
sample dissolver (7.5); add 5 mL of ammonia solution (6.2); cover the crucible lid; put
it into the steel sleeve; tighten it; put it in the digital temperature control oven (7.3);
control the temperature at 185 °C ± 5 °C and heat for 15 h.
9.3.2 After cooling, open the lid, and take out the inner tank; use water to transfer the
solution in the inner tank together with the precipitate into a 10 mL graduated test tube
(7.6); use water to dilute to the mark; shake well.
9.3.3 Leave to settle or use a centrifuge (7.4) to centrifuge. This is the test portion
solution.
9.4 Determination
Start the instrument according to the conditions specified in the instrument operating
instructions. For working conditions, see Table A.1 in Appendix A. Select the analysis
element isotope and the internal standard element isotope. The relevant isotopes are
shown in Table A.2. Prepare the sample analysis table. The instrument shall be stable
for at least 30 minutes after ignition. Use the mixed mass spectrometry tuning solution
(6.4) to optimize the instrument parameters. Introduce the rhenium internal standard
solution (6.9) online through the tee; measure the concentration values of the iodine
element in the calibration solution (6.8), full reagent blank solution (9.1), standard
material solution (9.2) and test portion solution (9.3.3) respectively.
9.5 Drawing of the calibration curve
Taking the mass concentration of iodine element in the calibration solution series as the
abscissa and the relative intensity of the mass spectrum signals of iodine element and
internal standard element as the ordinate, establish a calibration curve. Find the
concentration value of iodine element in the test portion solution from the calibration
curve.
10 Test data processing
The content of iodine (wi) to be measured in the sample is measured as mass fraction
[in micrograms per gram (μg/g)], and calculated according to Formula (1):
Where:
ρi – the mass concentration of the component to be measured in the test portion
measurement solution, in nanograms per milliliter (ng/mL);
ρi0 – the mass concentration of the component to be measured in the blank test solution
(9.1), in nanograms per milliliter (ng/mL);
V0 – the total volume of the test portion solution, in milliliters (mL);
w (H2O-) – the mass fraction of water adsorbed by the sample, calculated as percentage
(%);
mi – test portion mass, in grams (g).
Express the results obtained in accordance with the provisions of GB/T 14505-2010:
××× μg/g, ××.× μg/g, ×.×× μg/g, 0.×× μg/g.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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