GB/T 5195.12-2016Fluorite - Determination of arsenic content - Atomic fluorescence spectrometry (English PDF)

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°C -- 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.

100 µg of arsenic. Or use a certified standard solution.

5 Instruments and equipment

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°C±2°C for 2 h. Cool them to room

temperature in a desiccator and set aside for later use.

7 Analysis steps

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.

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