GOST 23862.3-79

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  ГОСТ 23862.3-79

GOST 23862.3−79 Samarium, europium, gadolinium, terbium, holmium, erbium, thulium, ytterbium, lutetium and their oxides. Spectral method of determination of impurities of oxides of rare earth elements (with Amendments No. 1, 2)

GOST 23862.3−79

Group B59

INTERSTATE STANDARD

SAMARIUM, EUROPIUM, GADOLINIUM, TERBIUM, HOLMIUM, ERBIUM, THULIUM, YTTERBIUM, LUTETIUM AND THEIR OXIDES

Spectral method of determination of impurities of oxides of rare earth elements

Samarium, europium, gadolinium, terbium, holmium, erbium, ytterbium, lutecium and their oxides. Spectral method of determination of impurities in oxides of rare-earth elements

ISS 77.120.99
AXTU 1709

Date of introduction 1981−01−01

The decision of the State Committee USSR on standards on October 19, 1979 N 3988 date of introduction is established 01.01.81

Limitation of actions taken by Protocol No. 7−95 Interstate Council for standardization, Metrology and certification (ICS 11−95)

EDITION with Amendments No. 1, 2 approved in April 1985, may 1990 (IUS 7−85, 8−90).


This standard specifies a method of determining the spectral impurity oxides of rare earth elements (REE) in Samaria, europium, gadolinium, terui, holmium, arbie, tuliya, ytterbium, the hotel Lutetia (previously translated into oxide) and their oxides.

The method is based on excitation and photographic registration of arc emission spectra of the analyte and sample comparison.

The mass fraction of rare earth impurities found by the calibration schedule.

The interval defined by the mass fraction of impurities of oxides:

(Changed edition, Rev. N 1).

1. GENERAL REQUIREMENTS

1.1. General requirements for method of analysis according to GOST 23862.0−79.

2. APPARATUS, MATERIALS AND REAGENTS

The diffraction spectrograph DFS-13 with a grating 1200 gr/mm or 2400 lines/mm operating in the first order reflection, from being a lighting system or similar.

The arc generator DG-2 with optional rheostat or similar, adapted to arc ignition of the AC high-frequency discharge.

Microphotometer geregistreerde type MF-2 or similar.

Microphotometer registered type GII or GIII with G1B1 recorder or similar.

Spectromancer of PS-18 or similar.

Analytical scale type ADV-200 or similar.

Libra torsion type VT-500 or similar.

Box of organic glass.

Mortar and pestle made of organic glass.

The mortar and pestle of jade.

Muffle furnace with thermostatic control, providing the temperature to 950 °C.

Crucibles porcelain 5 N.

The machine tool for sharpening of electrodes.

Coals spectral high purity-7−3, with a diameter of 6 mm.

The electrodes are machined from a spectral coals high purity-7−3, with a diameter of 6 mm:

electrodes of the type «glass» with a wall thickness of 1 mm, a height of the outer wall is 4 mm, the height of the «legs» 2 mm thick «legs» 2 mm:

the crater depth 3 mm, diameter 4 mm (I),

the crater depth of 2 mm, diameter 4 mm (Ia),

the crater depth 5 mm, diameter 2 mm (IB),

the crater depth 4 mm, diameter 4 mm (IB),

the crater depth 3 mm, diameter 4.5 mm — (G);

electrodes with the sharpened part of the height 10 mm, diameter 2 mm:

the crater depth of 2 mm, wall thickness 0.7−0.8 mm — (II),

the crater depth of 2 mm, wall thickness 1 mm (III),

the crater depth of 3 mm, wall thickness 0.7−0.8 mm (IV),

the crater depth of 3 mm, wall thickness 1 mm (V),

the crater depth 5 mm, wall thickness 0.7−0.8 mm — (VI),

the crater depth 5 mm, thickness 1 mm, — (VII);

electrodes with the sharpened part of the height 10 mm, diameter 1.5 mm:

the crater depth of 4 mm, wall thickness 0.7−0.8 mm (VIII).

Graphite powder of high purity according to GOST 23463−79.

Tracing paper according to GOST 892−89.

Medical compress according to NTD or hygroscopic GOST 5556−81.

Stopwatch mechanical.

Spectrographic plates of the type ES and type II sensitivity 15 units or equivalent, providing normal blackening of analytical lines.

Rectified ethyl alcohol GOST 18300−87.

Hydrochloric acid by the GOST 3118−77, H. h., diluted 1:1 and 1% solution.

Oxalic acid according to GOST 22180−76, H. C., saturated water and a 0.1% solution.

Ammonia water according to GOST 3760−79.

The cesium chloride.

Sodium fluoride according to GOST 4463−76.

Lithium fluoride.

Lithium carbonate.

Buffer a mixture of 1 — graphite powder containing 5% cesium chloride: 5 g of cesium chloride was mixed with 95 g of powder graphite in a mortar made of organic glass, was stirred for 3 h, adding the alcohol, maintaining the mass in a pasty condition. The mixture is dried in a drying Cabinet at a temperature of 100−105 °C for 4 h.

Buffer a mixture of 2 — graphite powder containing 10% sodium chloride: 10 g of sodium chloride is mixed with 90 g of powder graphite in a mortar of Jasper, stirred for 1 h, adding the alcohol, maintaining the mass in a pasty condition. The mixture is dried in an oven at 100−105 °C for 1 h.

Buffer a mixture of 3 — graphite powder containing 5% of lithium fluoride and 5% lithium carbonate 5 g of lithium fluoride and 5 g of lithium carbonate was mixed with 90 g of powder graphite in a mortar made of organic glass, was stirred for 3 h, adding the alcohol, maintaining the mass in a pasty condition. The mixture is dried in a drying Cabinet at a temperature of 100−105 °C for 4 h.

A buffer is a mixture of 4 — graphite powder containing 10% of sodium fluoride 10 g of sodium fluoride was mixed with 90 g of powder graphite in a mortar made of organic glass, was stirred for 3 h, adding the alcohol, maintaining the mass in a pasty condition. The mixture is dried in a drying Cabinet at a temperature of 100−105 °C for 4 h.

A buffer mixture of 5 — graphite powder containing 10% lithium carbonate: 10 g lithium carbonate was mixed with 90 g of powder graphite in a mortar of Jasper, stirred for 1 h, adding the alcohol, maintaining the mass in a pasty condition. The mixture is dried in a drying Cabinet at a temperature of 100−105 °C for 1 h.

Oxide of neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, clean-defined impurities.

Standard solutions of neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, yttrium containing 10 mg/cmof one of these REE in the calculation of the oxide. Each solution is prepared separately. 1 g of the appropriate oxide of re is placed in a beaker with a capacity of 100 cm, add 10 cmof hydrochloric acid 1:1, heated to complete dissolution, cooled, transferred to a volumetric flask with a capacity of 100 cm, the volume was adjusted with distilled water to the mark and mix.

Working solutions for the preparation of the samples for each of the REE oxides are prepared by successive dilution of the corresponding mixtures of standard solutions determined by the REE.

Working solutions containing 1 mg/cmof each of the identified elements in the calculation of its oxide: in a volumetric flask with a capacity of 100 cmplaced at 10 cmstandard solutions of the respective REE listed in table.1, and the volume was adjusted to the mark with 1% solution of hydrochloric acid.

Working solutions B containing 0.1 mg/cmof each of the identified elements in the calculation of its oxide is prepared by appropriate dilution of solution A to 10 times a 1% solution of hydrochloric acid. The compositions of the working solutions are given in table.1.

Table 1

Working solutions, containing 0.01 mg/cmof each of the identified elements in the calculation of its oxide, is prepared by appropriate dilution of a solution 10 times with 1% hydrochloric acid. The compositions of the working solutions are given in table.1.

Sec. 2. (Changed edition, Rev. N 1).

3. PREPARATION FOR ASSAY

3.1. Sample preparation comparison

Each reference sample (OS) is prepared before the photographing of the spectrum by mixing samples of the REE oxides with the powder graphite in a ratio of 1:1.

3.2. Preparation of samples for oxide REE

10 g of an oxide of re, clean at the designated impurities was placed in a beaker with a capacity of 1000 cm, moisten with water, add 100 cmof hydrochloric acid diluted 1:1, and heated to complete dissolution.

The solution is evaporated to wet salts, dissolved in 100 cmof distilled water and the resulting solution was introduced working solutions A, B or C in amounts shown in table.2−8 (a-e).

Table 2

Samples of the oxide of gadolinium (OOGD)

Table 3

Samples on oxide holmium (independent operational group)

Table 4

Table 5

Samples of the oxide of erbium (OOA)

Table 6

Table 7

Samples of an oxide of ytterbium (OOI)

Table 8

Table 8A

Samples of samarium oxide (OEM)

Table 8b

Samples on oxide europium (OOE)

Table 8b

Samples of the oxide of gadolinium (Oogd)

Table 8G

Samples on oxide terbium (OOM)

Table 8D

Samples on oxide thulium (Ootw)

Table 8E

Samples on lutetium oxide (Oolu)

After mixing the solutions, add distilled water to a volume of 500−600 cmand the ammonia to pH 1.5−2. The solution is heated to boiling, add 150 cmof hot saturated solution of oxalic acid. Solution and the precipitate was kept for 24 h. the Precipitate was filtered off through a filter with a blue ribbon, washed with 20 cmof a 0.1% solution of oxalic acid, placed in a porcelain crucible, dried on a hotplate and calcined in a muffle furnace at 900 °C to constant weight. Calcined oxide is stored in a desiccator in packages of tracing paper.

Mass batches of oxides REE 10 g. the Composition, concentration and quantity of cmadded working solutions of oxides defined by the REE are given in table.2−8 (a-e).

4. ANALYSIS

4.1. The analyzed sample or sample to oxides of REE mixed with an equal quantity of powdered graphite or a buffer mixture in a mortar of Jasper to obtain a homogeneous mixture. The mixture is poured onto a piece of tracing paper to the top and tightly fill the craters of the electrodes by repeated immersion of the electrode into the mixture. The dimensions of the electrodes are given in sect.2.

Two electrodes filled with sample or reference sample, is placed in the tripod vertically, with the craters towards each other. The spectra are photographed on a spectrograph DFS-13. The spectrum of the sample and the reference sample recorded on the plate three times.

Exposed photographic plates show washed with water, fixed, washed in running water for 15 min and dried.

4.2. Analysis of gadolinium or of its oxides

Gadolinium is converted into the oxide according to GOST 23862.0−79.

4.2.1. Determination of oxides of yttrium

A portion of the sample or each sample ООГД1-ООГД4 a mass of 240 mg (see table.2) is mixed with 240 mg of a mixture of buffer 1 and are placed (see p.4.1) six electrodes I. Between the electrodes ignite the arc AC 14 A. Photograph spectra with an exposure of 120 s. the distance between the electrodes during the exposure is maintained at 2 mm.

The spectra photographed in the region of wavelengths 300,0−330,0 nm using the spectrograph DFS-13 with grating 2400 lines/mm, the slit Width of the spectrograph 20 microns. In the cassette of the charge spectrograph a photographic plate of the type II.

(Changed edition, Rev. N 2).

4.3. Analysis of holmium oxide or

Transferred to the holmium oxide according to GOST 23862.0−79.

4.3.1. Determination of oxides of dysprosium

A portion of the sample or each sample ООГ1-ООГ4 (see table.3) weighing 60 mg are mixed with 60 mg of graphite powder and placed in craters of the six electrodes IV (see p.4.1).

Between the electrodes ignite the arc AC 14−15 A. Photographing spectra with an exposure of 90 s. the distance between the electrodes during the exposure is maintained at 2 mm.

The spectra photographed in the region of wavelengths 420,0−425,0 nm using the spectrograph DFS-13 with grating 2400 lines/mm (see p.4.1). The width of the slit of a spectrograph 20 microns. In the cassette spectrograph charge plate type II.

4.3.2. Determination of oxides of erbium and yttrium

A portion of the sample or each sample ООГ5-ООГ10 (see table.4) weighing 60 mg are mixed with 60 mg of graphite powder and placed in craters of the six electrodes IV (see p.4.1). Between the electrodes ignite the arc AC 14−15 A. Photographing range to complete combustion of the sample (~90). The distance between the electrodes during the exposure is maintained at 2 mm.

The spectra photographed in the region of wavelengths 390,0−410,0 nm using the spectrograph DFS-13 with grating 2400 lines/mm (see p.4.1). The width of the slit of a spectrograph 15 microns. In the cassette spectrograph charge plate type II.

4.4. Analysis of erbium oxide or

Transferred to the erbium oxide according to GOST 23862.0−79.

4.4.1. Determination of oxides of dysprosium, holmium, thulium, yttrium

A portion of the sample or each sample ООЭ1-ООЭ5 (see table.5) weighing 50 mg was mixed with 50 mg of powdered graphite and placed in craters of the six electrodes III (see p.4.1).

Between the electrodes ignite the arc AC of 12−13 A. taking Pictures range with an exposure of 90 s. the distance between the electrodes during the exposure is maintained at 1.5 mm.

The spectra photographed in the region of wavelengths 310,0-to 350.0 nm using the spectrograph DFS-13 with a grating 1200 lines/mm (see p.4.1). The width of the slit of a spectrograph 15 microns. In the cassette spectrograph charge plate type ES.

4.4.2. Determination of oxides of ytterbium

A portion of the sample or each sample ООЭ6-ООЭ9 (see table.6) weighing 50 mg was mixed with 50 mg of powdered graphite and placed in craters of the six electrodes III (see p.4.1). Between the electrodes ignite the arc AC of 12−13 A. taking Pictures range with an exposure of 60 s. the distance between the electrodes during the exposure is maintained at 1.5 mm.

Range photographed in the region of wavelengths 390,0−400,0 nm using the spectrograph DFS-13 with a grating 1200 lines/mm (see p.4.1). The width of the slit of a spectrograph 12 microns. In the cassette spectrograph charge plate type ES.

4.5. Analysis of ytterbium oxide or

Ytterbium is transferred to the oxide according to GOST 23862.0−79.

4.5.1. Determination of oxides of erbium, thulium, yttrium

A portion of the sample or each sample ООИ1-ООИ6 (see table.7) mass of 50 mg mixed with 50 mg of powdered graphite and placed in a crater of six electrodes (see p.4.1).

Between the electrodes ignite the arc AC 14−15 A. Photographed with the exposure range 105 Prebake for 15 s. the distance between the electrodes during the exposure is maintained at 2 mm.

The spectra photographed in the region of wavelengths 310,0−335,0 nm using the spectrograph DFS-13 with a grating 1200 lines/mm (see p.4.1). The width of the slit of a spectrograph 15 microns. In the cassette spectrograph charge plate type ES.

4.5.2. Determination of the oxides of lutetium

A portion of the sample or each sample ООИ7-ООИ11 (see p.3.2 table.8) weighing 60 mg are mixed with 60 mg of graphite powder and placed in craters of the six electrodes IV (see p.4.1).

Between the electrodes ignite the arc AC 14−15 A. taking Pictures range with an exposure of 90 s. the distance between the electrodes during the exposure is maintained at 2 mm.

The spectra photographed in the region of wavelengths 260,0: 270.0 cm nm using the spectrograph DFS-13 with a grating 1200 lines/mm (see p.4.1). The width of the slit of a spectrograph 15 microns. In the cassette spectrograph charge plate type ES.

4.6. Analysis of samarium and its oxides

Samarium transferred to the oxide according to GOST 23862.0−79.

4.6.1 Determination of oxides of europium

A portion of the sample and each sample ООСм1-ООСм5 weighing 180 mg was placed in the craters of three graphite electrodes of the type «glass» (Ia). When filling electrodes, the samarium oxide is poured on a piece of tracing paper to the top and tightly fill the craters of the electrodes by repeated immersion of the electrode into the oxide of samarium. Serves as a counter electrode (VII) filled with buffer 2 mixture.

Two electrodes filled with sample or reference sample, is placed in the tripod vertically, with the craters towards each other. The anode is the electrode filled with the sample or the reference sample, the cathode electrode filled with a buffer mixture. Between the electrodes ignite the arc of direct current strength of 10 A. the spectra Photographed with an exposure of 60 s. the distance between the electrodes during the exposure is maintained at 3 mm. Spectra photographed in the region of wavelengths 285,0−300,0 nm using the spectrograph DFS-13 with grating 2400 lines/mm, the slit Width of the spectrograph 20 microns. In the cassette of the charge spectrograph a photographic plate type II.

4.6.2. Determination of oxides of neodymium, gadolinium

A portion of the sample and each reference sample ООСм1-ООСм5 a mass of 40 mg is mixed with 120 mg of graphite powder in a mortar of Jasper until a homogeneous mass. The mixture is poured onto a piece of tracing paper to the top and tightly fill the craters of the twelve graphite electrodes (VIII). Two electrodes filled with sample or reference sample, is placed in the tripod vertically, with the craters towards each other. Between the electrodes ignite the arc of an alternating current power 15 A and the photographing range of exposure 90 s. the distance between the electrodes during the exposure support 3 mm.

The spectra photographed in the region of wavelengths 425,0−435,0 nm (in the determination of neodymium) and 300,0−310,0 nm (in the determination of gadolinium) by using the spectrograph DFS-13 with grating 2400 lines/mm, the slit Width of the spectrograph 20 microns. In the cassette of the charge spectrograph a photographic plate type II.

4.7. Analysis of europium oxide or

Europium is transferred to the oxide according to GOST 23862.0−79.

4.7.1. Determination of oxides of neodymium, samarium, gadolinium

A portion of the sample and each reference sample OOE1-ООЕ4 mass of 100 mg was mixed with 400 mg of graphite powder in a mortar of Jasper to obtain a homogeneous mixture. The mixture was poured onto tracing paper and dip the electrode into the mixture tightly filled up to the top six graphite electrodes (I). Two electrodes filled with sample or reference sample, is placed in the tripod vertically with craters towards each other. Between the electrodes ignite the arc AC of 15−16 A. Photographing spectra with an exposure of 80 after a preliminary roasting for 60 s with a closed slit of a spectrograph. The spectra photographed in the region of wavelengths of 385 nm. The width of the slit of a spectrograph 15 microns. In the cassette spectrograph charge plate type II.

4.8. Analysis of gadolinium or of its oxides

Gadolinium is converted into the oxide according to GOST 23862.0−79.

4.8.1. Determination of oxides of samarium, terbium, dysprosium, yttrium

A portion of the sample and each reference sample ООГда1-ООГДа9 weight of 300 mg mixed with 100 mg of a mixture of buffer 3 in a mortar of Jasper until a homogeneous mass. The mixture is poured onto a piece of tracing paper and multiple dip electrodes in a mixture of tightly filled up to the top craters of the electrodes (G). The electrode with the sample or the reference sample serves as the anode, the cathode is the electrode (V) filled with buffer mixture 4. Between electrodes to ignite an arc DC current of 13 A. the exposure Time 90 s. the Spectra are photographed on a spectrograph DFS-13 with a grating 1200 lines/mm in the region 410,0−440,0 nm. In the cassette load plate type II.

4.8.2. Determination of oxides of europium

A portion of the sample and each reference sample ООГда10-ООГда17 mass of 40 mg was placed in an electrode (IB) and tapping on the electrode to achieve a uniform distribution of samples in channel volume. To the electrode (VII) was placed buffer mixture 2 by repeated immersion in it of the electrode. Between electrodes to ignite an arc DC current of 10 A. with the sample Electrode is an anode, the electrode with the buffer mixture as the cathode. The distance between the electrodes is supported by 2 mm. the Spectra are photographed on a spectrograph DFS-13 with a grating 1200 lines/mm in the region of 460 nm. Exposure time 30 s In the cassette spectrograph a photographic plate load type II.

4.9. Analysis of the terbium or its oxide

Transferred to terbium oxide according to GOST 23862.0−79.

4.9.1. Determination of the oxides of gadolinium

A portion of the sample and each reference sample ООТ1-ООТ5 mass of 100 mg was mixed with 100 mg of buffer mix 5 and placed in craters of the six graphite electrodes (VI). Between the electrodes ignite the arc AC 14−15 A. the exposure Time 90 s. the distance between the electrodes during the exposure support 2 mm.

The spectra photographed in the region of wavelengths 295,0−305,0 nm using the spectrograph DFS-13 with grating 2400 lines/mm, the slit Width of the spectrograph 20 microns. In the center of the cassette spectrograph a photographic plate load type II.

4.9.2. Determination of oxides of dysprosium

A portion of the sample and each reference sample ООТ1-ООТ5 a weight of 150 mg was mixed with 150 mg of powdered graphite and placed in craters of the six graphite electrodes (Ia). Between the electrodes ignite the arc AC 14−15 A. the exposure Time 90 s. the distance between the support electrodes 2 mm.

The spectra photographed in the region of wavelengths 410,0−425,0 nm using the spectrograph DFS-13 with grating 2400 lines/mm, the slit Width of the spectrograph 17 microns. In the cassette of the charge spectrograph a photographic plate type ES.

4.9.3. Determination of oxides of yttrium

A portion of the sample and each reference sample ООТ1-ООТ5 weight of 90 mg was mixed with 90 mg of graphite powder and placed in craters of the six electrodes (VI). Between the electrodes ignite the arc AC 14−15 A. the exposure Time 90 s. the distance between the electrodes during the exposure is maintained at 2 mm.

The spectra photographed in the region of wavelengths 320,0−330,0 nm using the spectrograph DFS-13 with grating 2400 lines/mm, the slit Width of the spectrograph 22 microns. In the cassette of the charge spectrograph a photographic plate of the type ES.

4.10. Analysis of thulium or its oxide

Tullius transferred to the oxide according to GOST 23862.0−79.

4.10.1. Determination of oxides of erbium, ytterbium

A portion of the sample and each reference sample OOTy1-ООТу5 weighing 60 mg are mixed with 60 mg of graphite powder and placed in craters of the six graphite electrodes (VIII). Between the electrodes ignite the arc AC 14−15 A. the exposure Time of 60 s. the distance between the electrodes during the exposure is maintained at 2 mm.

The spectra photographed in the region of wavelengths 322,5−330,0 nm using the spectrograph DFS-13 with grating 2400 lines/mm, the slit Width of the spectrograph 15 microns. In the cassette of the charge spectrograph a photographic plate type II.

4.10.2. Determination of the oxides of lutetium

A portion of the analyzed oxides of thulium or each reference sample OOTy1-ООТу5 weight of 80 mg was mixed with 80 mg of graphite powder and placed in craters of the six graphite electrodes (VI). Between the electrodes ignite the arc AC 14−15 A. the exposure Time of 60 s. the distance between the electrodes is maintained at 2 mm.

The spectra photographed in the region of wavelengths 255,0−265,0 nm using the spectrograph DFS-13 with a grating 1200 lines/mm, the slit Width of the spectrograph 20 microns. In the cassette of the charge spectrograph a photographic plate type ES.

4.11. Analysis of lutetium oxide or

Lutetium is converted into the oxide according to GOST 23862.0−79.

4.11.1. Determination of oxides of erbium, thulium, ytterbium

A portion of the sample and each reference sample ООЛю1-ООЛю7 weighing 60 mg are mixed with 60 mg of graphite powder in a mortar of Jasper until a homogeneous mass. The mixture is poured onto a piece of tracing paper to the top and tightly fill the six craters of graphite electrodes; (IV) repeated immersion of the electrodes into the mixture. Two electrodes filled with sample or reference sample, is placed in the tripod vertically, with the craters towards each other. Between the electrodes ignite the arc AC 14−15 A. Exposure of 60 s. the distance between the electrodes during the exposure is maintained at 2 mm.

The spectra photographed in the region of wavelengths 310,0−335,0 nm using the spectrograph DFS-13 with a grating 1200 lines/mm, the slit Width of the spectrograph 15 microns. In the cassette of the charge spectrograph a photographic plate type II.

4.6−4.11. (Added, Rev. N 1).

5. PROCESSING OF THE RESULTS

In each spectrogram photometric blackening of analytical lines of the designated element and the line of comparison, or of the logarithm of the ratio of the intensities of the analytical lines and the background in the spectra of samples and sample comparison.

5.1 a. Using microphotometer MF-2 photometric blackening of analytical lines of the designated element and lines of comparison or background and calculate the difference of pochernenija

or .

Three parallel values , , obtained three spectrograms taken for each sample, find the arithmetic mean of the results . Values and comparison of samples for build calibration curve in the coordinates (, ). Mass fraction of impurities determined in the sample find the schedule for the calibration value for the sample obtained three spectrograms taken for the sample.

(Added, Rev. N

1).

5.1. With the help of registered microphotometry in each spectrogram record the outline of the analytical lines of the designated element (see table.9) and the surrounding background. Then on the resulting registrarme measure the magnitude (the distance from the line of the dark current to the highest point of the contour line in millimeters) and magnitude (the distance from the line of the dark current to a point lying near the base of the contour lines) and calculate the value

.

Table 9

Three spectrograms taken for each sample, calculating the logarithm of the ratio of intensity of lines of the designated element to the background intensity

; ; .

Find the arithmetic mean .

Values and comparison of samples for build calibration curve in the coordinates . On this schedule the calibration value for the analyzed samples was found as the arithmetic mean of results of three parallel measurements, find the contents of the designated impurities in the sample.

(Changed edition, Rev. N 1).

5.2. The discrepancy between the results of three parallel measurements (the ratio of highest result to lowest), and the discrepancy between the results of two tests (a ratio greater outcome to a lesser) should not exceed the values of permissible differences given in table.10.

Table 10

5.3. Under the control of the reproducibility of parallel determinations from three values , and obtained three spectrograms of samples, choose the greater and the lesser values and find the appropriate graphics for the calibration of mass fractions of impurities. Discrepancies between the obtained results (ratio of largest to smallest) should not exceed the values of permissible differences given in table.10.

Under the control of the reproducibility of parallel determinations from three values ; ; obtained three spectrograms of a sample, select the largest and smallest values, and find the calibration schedule appropriate to the content of impurities. Differences between the thus obtained results of three parallel measurements (the ratio of highest result to lowest) shall not exceed the values allowable differences specified in table.10.

(Changed edition, Rev. N 1).