GB/T 5195.12-2016 PDF English
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Fluorite - Determination of arsenic content - Atomic fluorescence spectrometry
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GB/T 5195.12-2016: PDF in English (GBT 5195.12-2016) GB/T 5195.12-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 73.080
D 52
Fluorite - Determination of arsenic content - Atomic
fluorescence spectrometry
ISSUED ON. DECEMBER 13, 2016
IMPLEMENTED ON. SEPTEMBER 01, 2017
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine of the People's Republic of China;
Standardization Administration of the People's Republic of China.
Table of Contents
Foreword... 3
1 Scope... 5
2 Normative references... 5
3 Principle... 6
4 Reagents... 6
5 Instruments and equipment... 7
6 Specimen... 7
7 Analysis steps... 7
8 Result calculation... 9
9 Precision... 9
10 Test report... 10
Annex A (normative) Flowchart of the procedure for accepting specimen analysis
results... 11
Annex B (informative) Raw data from precision tests... 12
Foreword
GB/T 5195 is divided into 12 parts.
- Part 1.Fluorite -- Determination of calcium fluoride content -- EDTA titration
method and distillation-potentiometric titration method;
- Part 2.Fluorspar -- Determination of carbonate content;
- Part 3.Fluorspar -- Determination of loss in mass at 105℃ -- Gravimetric method;
- Part 4.Fluorspar -- Determination of sulfide content -- Iodometric method;
- Part 5.Fluorspar -- Determination of total sulfur content -- The iodometric method
after combustion;
- Part 6.Fluorspar -- Determination of phosphorus content;
- Part 7.Fluorspar -- Determination of zinc content -- Flame atomic absorption
spectrophotometric method;
- Part 8.Fluorspar -- Determination of silicon dioxide content;
- Part 9.Fluorspar -- Determination of loss on ignition -- Gravimetric method;
- Part 10.Fluorspar -- Determination of iron content -- 1, 10-phenanthroline
spectrophotometric method;
- Part 11.Fluorspar -- Determination of manganese content -- Periodate
spectrophotometry and flame atomic absorption spectrometry;
- Part 12.Fluorite -- Determination of arsenic content -- Atomic fluorescence
spectrometry.
This is Part 12 of GB/T 5195.
This Part was drafted in accordance with the rules given in GB/T 1.1-2009.
This Part was proposed by China Iron and Steel Association.
This Part shall be under the jurisdiction of National Technical Committee on Steel of
Standardization Administration of China (SAC/TC 183).
The drafting organizations of this Part. Shanghai Entry-Exit Inspection and Quarantine
Bureau Industrial Products and Raw Materials Testing Technology Center,
Metallurgical Industry Information Standards Research Institute.
Fluorite - Determination of arsenic content - Atomic
fluorescence spectrometry
WARNING -- Personnel using this part shall have practical experience in regular
laboratory work. This part does not point out all possible safety issues. Users are
responsible for taking appropriate safety and health measures and ensuring that
the conditions specified in relevant national laws and regulations are met.
1 Scope
This Part of GB/T 5195 specifies the determination of arsenic content by hydride
generation-atomic fluorescence spectrometry.
This Part applies to the determination of arsenic content in fluorite. Determination range
(mass fraction). 0.00001%~0.010%.
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, Measurement methods and results -- Accuracy (trueness and precision)
-- Part 2.Determine the standard methods of measurement repeatability and
reproducibility of the basic method
GB/T 6682, Water for analytical laboratory use -- Specification and test methods
GB/T 8170, Rules of rounding off for numerical values and expression and
judgement of limiting values
GB/T 12806, Laboratory glassware -- One-mark volumetric flasks
GB/T 12807, Laboratory glassware -- Graduated pipettes
GB/T 12808, Laboratory glassware -- One mark pipettes
GB/T 21191, Atomic fluorescence spectrometer
GB/T 22564, Fluorspar -- Sampling and sample preparation
3 Principle
The test material is dissolved with nitric acid and perchloric acid. In a dilute
hydrochloric acid medium, a thiourea-ascorbic acid mixed solution is added to reduce
arsenic (V) to arsenic (III). In the hydride generator, arsenic is reduced to hydride by
potassium borohydride. Argon gas is introduced into the quartz furnace atomizer. The
fluorescence intensity of arsenic is measured on an atomic fluorescence spectrometer.
The arsenic content is calculated according to the standard curve method.
4 Reagents
Unless otherwise specified, only analytically pure reagents shall be used. Water shall
be deionized water or water of equivalent purity, which shall comply with the
requirements for grade two in GB/T 6682.
4.1 Potassium borohydride.
4.2 Sodium hydroxide.
4.3 Thiourea.
4.4 Ascorbic acid.
4.5 Hydrochloric acid, ρ =1.19 g/mL.
4.6 Nitric acid, ρ =1.42 g/mL.
4.7 Perchloric acid, ρ =1.76 g/mL.
4.8 Hydrochloric acid, 1+1.
4.9 Hydrochloric acid, 1+19.
4.10 Nitric acid, 1+9.
4.11 Sodium hydroxide solution, 100 g/L.
4.12 Phenolphthalein ethanol solution, 1 g/L.
4.13 Potassium borohydride solution, 20 g/L. Weigh 10.0 g of potassium borohydride
and 2.5 g of sodium hydroxide. Dissolve in water and dilute to 500 mL. Prepare when
needed.
4.14 Thiourea-ascorbic acid solution, 50 g/L. Weigh 5.0 g each of thiourea and ascorbic
acid. Dissolve them in water. Dilute to 100 mL. Prepare when needed.
4.15 Arsenic standard stock solution, 100 μg/mL. Accurately weigh 0.1320 g of
standard arsenic trioxide that has been pre-dried at 100℃~105℃ for 1 h and cooled to
room temperature in a desiccator into a 100 mL beaker. Add 10 mL of sodium hydroxide
solution (4.11). Heat at low temperature to dissolve. Add 10 mL of water and 2 drops
of phenolphthalein ethanol solution (4.12). Neutralize with hydrochloric acid (4.8) until
the red color just disappears. Add another 5 mL in excess. Transfer to a 1000 mL
volumetric flask. Dilute to the mark with water. Mix well. 1 mL of this solution contains
100 μg of arsenic. Or use a certified standard solution.
4.16 Arsenic standard solution, 1 μg/mL. Take 1.00 mL of arsenic standard stock
solution (4.15) in a 100 mL volumetric flask. Add 5 mL of nitric acid (4.6). Dilute to
the mark with water. Shake well. This solution contains 1.00 μg of arsenic in 1 mL.
5 Instruments and equipment
5.1 Atomic fluorescence spectrometer. equipped with hydride generator and sample
injection device, dedicated arsenic hollow cathode lamp, meeting the requirements of
GB/T 21191.
5.2 Controllable temperature heating plate. temperature range 50℃~350℃.
5.3 Analytical balance. sensitivity 0.1 mg.
5.4 Argon. purity greater than 99.99%.
5.5 Polytetrafluoroethylene beaker.
5.6 Volumetric flask. 50 mL, 100 mL, in accordance with GB/T 12806.
5.7 Pipette. 0.5 mL~5.0 mL, 10 μL~1 000 μL, in accordance with the requirements of
GB/T 12807 and GB/T 12808.
NOTE. The polytetrafluoroethylene beakers and volumetric flasks used in the experiment are
soaked in nitric acid (1+9) for more than 24 h, rinsed with water, dried and set aside for later use.
6 Specimen
Prepare chemical analysis specimens with a particle size of less than 63 μm according
to GB/T 22564.Dry the specimens in an oven at 105℃±2℃ for 2 h. Cool them to room
temperature in a desiccator and set aside for later use.
7 Analysis steps
7.1 Test material
blank solution from the fluorescence intensity of the sample solution. Obtain the
corresponding arsenic concentration from the calibration curve.
8 Result calculation
Calculate the arsenic content in the sample according to formula (1), in mass fraction
(%).
Where,
w - the content of arsenic in the sample, %;
c - the concentration of arsenic in the sample solution obtained from the working curve,
in nanograms per milliliter (ng/mL);
V0 - the total volume of the test solution, in milliliters (mL);
V1 - the volume of the test solution taken, in milliliters (mL);
V2 - the volume of the test solution measured, in milliliters (mL);
m0 - the mass of the test material, in grams (g).
The numerical rounding shall be carried out in accordance with the provisions of GB/T
8170.When 0.00001≤w< 0.001, the result shall be rounded to two significant figures.
When 0.001≤w< 0.010, the result shall be rounded to three significant figures.
9 Precision
The precision data of this section are determined by collaborative testing of 5 levels of
arsenic content by 10 laboratories in 2015.Each laboratory measures each level of
arsenic content three times. The original data are statistically analyzed according to
GB/T 6379.1 and GB/T 6379.2.The repeatability limit and reproducibility limit are
calculated. The precision is shown in Table 2.
The procedure for accepting sample analysis results shall be handled in accordance with
the process in Annex A. The original data of precision determination is shown in Annex
B.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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