GOST R 56306-2014

• gost-r-56306-2014.pdf (657.61 KiB)
  ГОСТ Р 56306-2014

GOST R 56306−2014 Silver. Method of atomic-emission analysis with inductively coupled plasma

GOST R 56306−2014

NATIONAL STANDARD OF THE RUSSIAN FEDERATION

SILVER

Method of atomic-emission analysis with inductively coupled plasma

Silver. Method of inductively coupled plasma atomic-emission analysis

OKS 77.120.99*

_____________________

* According to the official website of Rosstandart OKS 39.060,

here and further. — Note the manufacturer’s database.

Date of introduction 2015−07−01

Preface

1 DEVELOPED by the Open joint-stock company «Irgiredmet» (JSC «Irgiredmet»), State scientific center State scientific-research and design Institute of rare metals industry (Giredmet SSC), an Open joint stock company «Krasnoyarsk factory of nonferrous metals named after V. N. Gulidova» (OJSC Krastsvetmet)

2 SUBMITTED by the Technical Committee on standardization TC 304 «Noble metals, alloys, industrial jewelry products, secondary resources containing noble metals"

3 APPROVED AND put INTO EFFECT by the Federal Agency for technical regulation and Metrology of December 12, 2014 N 1990-St

4 INTRODUCED FOR THE FIRST TIME


Application rules of this standard are established in GOST R 1.0−2012 (section 8). Information about the changes to this standard is published in the annual (as of January 1 of the current year) reference index «National standards» and the official text changes and amendments — in monthly information index «National standards». In case of revision (replacement) or cancellation of this standard a notification will be published in a future issue of information index «National standards». Relevant information, notification and lyrics are also posted in the information system of General use — on the official website of the Federal Agency for technical regulation and Metrology on the Internet (gost.ru)

1 Scope

This standard applies to refined silver with a mass fraction of silver is not less than 99.8%.

The standard specifies atomic emission with inductively coupled plasma method for the determination of impurities, aluminum, bismuth, iron, gold, cadmium, cobalt, silicon, magnesium, manganese, copper, arsenic, Nickel, tin, palladium, platinum, rhodium, lead, selenium, antimony, tellurium, titanium, chromium and zinc in affilirovannomu silver.

2 Normative references

This standard uses the regulatory references to the following standards:

GOST R 8.563−2009 State system for ensuring the uniformity of measurements. Techniques (methods) of measurements

GOST R ISO 5725−1-2002 Accuracy (trueness and precision) of methods and measurement results. Part 1. General provisions and definitions

GOST R ISO 5725−3-2002 Accuracy (trueness and precision) of methods and measurement results. Part 3. Intermediate indicators the precision of a standard measurement method

GOST R ISO 5725−4-2002 Accuracy (trueness and precision) of methods and measurement results. Part 4. The main methods of determining the correctness of a standard measurement method

GOST R ISO 5725−6-2002 Accuracy (correctness and precision) of methods and measurement results. Part 6. The use of precision values in practice

GOST R 52244−2004 Palladium refined. Specifications

GOST R 52245−2004 Platinum affilirovannaja. Specifications

GOST R 52361−2005 Control of the analytical object. Terms and definitions

GOST R 52501−2005 (ISO 3696:1987) Water for laboratory analysis. Specifications

GOST R 52599−2006 Precious metals and their alloys. General requirements for methods of analysis

GOST R 53228−2008 Scales non-automatic actions. Part 1. Metrological and technical requirements. Test

GOST 123−2008 Cobalt. Specifications

GOST 804−93 primary Magnesium ingots. Specifications

GOST 849−2008 Nickel primary. Specifications

GOST 859−2014 Copper. Brand

GOST 860−75 Tin. Specifications

GOST 1089−82 Antimony. Specifications

GOST 1467−93 Cadmium. Specifications

GOST 1770−74 (1042−83 ISO, ISO 4788−80) Glassware volumetric laboratory glass. Cylinders, beakers, flasks, test tubes. General specifications

GOST 3640−94 Zinc. Specifications

GOST 3778−98 Lead. Specifications

GOST 4328−77 Reagents. Sodium hydroxide. Specifications

GOST 5905−2004 (ISO 10387:1994) metal Chrome. Technical requirements and delivery conditions

GOST 6008−90 metallic Manganese and nitrated manganese. Specifications

GOST 6835−2002 Gold and alloys on its basis. Brand

GOST 9428−73 Reagents. Silicon (IV) oxide. Specifications

GOST 10157−79 Argon gaseous and liquid. Specifications

GOST 10298−79 Selenium technical. Specifications

GOST 10928−90 Bismuth. Specifications

GOST 11069−2001 primary Aluminium. Brand

GOST 11125−84 nitric Acid of high purity. Specifications

GOST 12342−81 Rhodium powder. Specifications

GOST 13610−79 carbonyl Iron radio. Specifications

GOST 14261−77 hydrochloric Acid of high purity. Specifications

GOST 14262−78 sulphuric Acid of high purity. Specifications

GOST 17614−80 Tellurium technical. Specifications

GOST 17746−96 spongy Titanium. Specifications

GOST 22861−93 Lead of high purity. Specifications

GOST 25336−82 Glassware and equipment laboratory glass. The types, basic parameters and dimensions

GOST 28058−89 Gold bullion. Specifications

GOST 28595−90 Silver bullion. Specifications

GOST 29227−91 (ISO 835−1-81) oils. Pipettes are graduated. Part 1. General requirements

Note — When using this standard appropriate to test the effect of reference standards in the information system of General use — on the official website of the Federal Agency for technical regulation and Metrology on the Internet or in the annual information index «National standards» published as on January 1 of the current year, and the editions of the monthly information index «National standards» for the current year. If replaced with a reference standard, which was given an undated reference, then it is recommended to use the current version of this standard, taking into account all enabled in this version modifications. If replaced with a reference standard, which is given a dated reference, it is recommended to use the version of this standard referred to above by year of approval (acceptance). If after approval of this standard in the reference standard, which is given a dated reference, a change affecting a provision to which reference, the provision is recommended to be applied without taking into account this change. If the reference standard is cancelled without replacement, the position in which reference is made to him, recommended to be used in part not affecting this link.

3 Terms and definitions

This standard applies the terminology according to GOST R 8.563, GOST R ISO 5725−1, GOST R 52361.

4 the essence of the method

The analysis method is based on excitation of atoms in the inductively coupled plasma and measuring the intensity of the analytical line of the designated chemical element (hereinafter, element) if you spray it pre-translated in the sample solution in the plasma. The relationship of the intensity of lines with the concentration of the element in the solution set by using the calibration characteristics.

The method allows to determine the mass fraction of impurities in the ranges given in table 1.


Table 1 — Ranges of mass fraction of detectable elements

Percentage

5 Accuracy (trueness and precision) of the method

5.1 indicators of the accuracy of the method

Indicators of accuracy of the method: limit of the interval in which with a probability of 0.95 is the absolute error of the results of the analysis standard deviation of repeatability , standard deviation, intermediate precision , standard deviation of reproducibility , the values of the limit of repeatability , intermediate precision and reproducibility limit depending on the mass fraction of the element-impurities are shown in table 2.


Table 2 — indicators of the accuracy of the method (0,95)

Percentage

For intermediate values of mass fraction of impurity elements the values of precision find using linear interpolation according to the following formula

, (1)

where  — the indicator of the accuracy of the analysis result;

, the values of precision, corresponding to the lower and upper level mass fraction of detectable elements, between which is the result of the analysis;

 — the result of the analysis;

, values of the lower and upper levels of the mass fraction of elements, between which there is the result.

5.2 Correctness

Systematic error of the method at a significance level of 5%, established in accordance with the requirements of GOST R ISO 5725−4 at all defined levels of mass fractions of impurities in silver to be insignificant.

5.3 Precision

Range of two results of determinations obtained for the same sample by one operator using the same equipment within the shortest possible time intervals that may exceed the specified in table 2, the limit frequency set in accordance with the requirements of GOST R ISO 5725−6, on average not more than once in 20 cases with proper use of the method.

Within a single laboratory result analysis of the same sample obtained by different operators using the same equipment on different days, can vary with the excess specified in table 2 of the limit of intermediate precision set in accordance with the requirements of GOST R ISO 5725−3, on average not more than once in 20 cases with proper use of the method.

The results of the analysis of the same samples, obtained in two laboratories (in accordance with sections 6−10), may vary with the excess specified in table 2 of the limit of reproducibility , established in accordance with the requirements of GOST R ISO 5725−1, on average not more than once in 20 cases with proper use of the method.

6 Requirements

6.1 General requirements for the method of analysis and security requirements — according to GOST R 52599.

6.2 To perform analysis allowed persons over the age of 18, trained in the prescribed manner and allowed to work independently on used equipment.

6.3 Sampling for analysis is carried out in accordance with GOST 28595 and technical documentation, adopted in the prescribed manner.

7 measuring instruments, auxiliary equipment, materials, reagents

7.1 measuring instruments

Atomic emission spectrometer with inductively coupled plasma, driven by external computer with certified software, an operating range of wavelengths from 180 to 500 nm and a correction procedure for the background.

Laboratory scales in accordance with GOST R 53228 with a limit of permissible absolute error of measurement no more than ±0,0003 g

Volumetric flasks 1−25−2, 1−50−2, 1−100−2 according GOST 1770.

Pipette 1−1-2−1, 1−1-2−5, 1−1-2−10 according to GOST 29227.

Beakers according GOST 1770 with a capacity of 50, 100, 250 and 1000 cm.

7.2 accessories

Muffle furnace with temperature control, heating temperature up to 1000 °C.

Electric stove with a closed coil and adjustable heating temperature up to 300 °C.

Drying oven with the temperature heating up to 150 °C.

7.3 Materials

Argon gas or liquid of the highest grade according to GOST 10157.

Funnel laboratory In-25−38 TC GOST 25336 or plastic.

Sealed containers of polyethylene, polypropylene or Teflon with a capacity of 50, 100 cm.

Sticks to glass.

Glasses In laboratory-1−50 TCS In-1−100 TCS-1−250 TCS according to GOST 25336.

The Teflon beakers with lids capacity 50 cm.

Hour glass or plastic.

The agate mortar.

The corundum crucibles.

The glassy carbon crucibles with a capacity of 50 cm.

Obestochennye the filter paper of «blue ribbon» «white ribbon» [1]*.
________________
* POS.[1]-[3] cm. Bibliography. — Note the manufacturer’s database.

7.4 Reagents

Aluminium metal according to GOST 11069.

Barium peroxide (barium peroxide) OS.h. in [2].

Bismuth GOST 10928.

Water for laboratory analysis 1 the degree of purity according to GOST R 52501.

Radio engineering carbonyl iron according to GOST 13610 or restored [3].

Gold bullion according to GOST 6835 or GOST 28058 with a mass fraction of main substance not less than 99.99%.

Cadmium GOST 1467.

Nitric acid of high purity according to GOST 11125 and diluted 1:1.

Sulfuric acid of high purity according to GOST 14262 and diluted 1:9.

Hydrochloric acid of high purity according to GOST 14261 and diluted 1:1, 1:5, 1:100.

Cobalt GOST 123.

Silicon dioxide according to GOST 9428.

Magnesium GOST 804.

Manganese metal according to GOST 6008.

Copper according to the GOST 859.

Arsenic metal, high purity [4].

Sodium hydroxide of high purity according to GOST 4328.

Nickel GOST 849.

Tin GOST 860.

Palladium refined according to GOST R 52244 with a mass fraction of the basic substance is not less than 99,98%.

Platinum affilirovannaja GOST R 52245 with a mass fraction of the basic substance is not less than 99,98%.

Rhodium powder according to GOST 12342 with a mass fraction of basic substance is no less than a 99.97%.

Lead of high purity according to GOST or GOST 22861 3778.

Selenium technical GOST 10298.

Antimony GOST 1089.

Tellurium GOST 17614.

Titanium sponge according to GOST 17746.

Chrome metal according to GOST 5905.

Zinc GOST 3640.

Allowed the use of other measuring instruments, auxiliary equipment, materials and reagents, subject to obtaining the metrological characteristics are not inferior to those in table 2.

8 Preparation for assay

8.1 Preparation of basic solutions

The following procedures for preparing basic solutions indicate the mass of batches of materials with a purity not lower of 99.96%. In the case of use of reagents with a purity lower than that specified in 7.4, then the correction of the mass of sample in accordance with a mass fraction of basic substance, specified in the passport in reagent.

The prepared solutions were stored at room temperature in sealed containers of glass and/or plastic not more than one year.

On the containers of solutions must be pasted label with the indication of the name or symbols of elements mass concentration of elements and the accuracy of its establishment, date of preparation and shelf life of the solution.

8.1.1 the Solution of the mass concentration of rhodium of 1 mg/cm

The weight of rhodium with a mass of 0.1 g is weighed with an accuracy of ±0.0003 g, thoroughly mixed in an agate mortar with five times the quantity of peroxide of barium to obtain a homogeneous mass. The resulting mixture is transferred to a corundum crucible, put in a cold muffle furnace and sintered at temperatures (950±50)°C for 2−3 h.

Crucible sintering was cooled to room temperature, transferred to a beaker with a capacity of 250 cm, sintered is moistened with water and treated with a solution of hydrochloric acid 1:1. The beaker was heated until complete dissolution of the cake, not bringing the solution to boiling. Cooled to room temperature, the solution was filtered through filter «blue ribbon». The filter 5−6 times washed with hot hydrochloric acid 1:5.

If the dark sediment filter it is transferred to a corundum crucible with the filter, dried in air, placed the crucible in a cold muffle furnace, include heating and calcined at a temperature of (750±50)°C for 30−40 min. the Cooled residue was triturated with five times the quantity of peroxide of barium, is sintered, dissolved, filtered as described above.

The filtrates are United, evaporated to a volume of 5−10 cm, dilute with water to volume of 50 cm, heated to boiling and precipitated barium sulfate in hot sulfuric acid 1:9. After 2−3 hours check the completeness of the precipitation of barium sulfate, adding a few drops of sulfuric acid 1:9. The solution was filtered through filter «blue ribbon» in a volumetric flask with a capacity of 100 cm, for washing the precipitate on the filter with hot hydrochloric acid 1:5, then 5−6 times with hot water. The solution was cooled, the volume was adjusted to the mark with hydrochloric acid 1:5 and stirred.

The error values of the mass concentration of rhodium in the solution is ±0.004 mg/cm.

8.1.2 Solutions with mass concentrations of gold, palladium, platinum, selenium, antimony, tellurium, cadmium, aluminum, tin 1 mg/cm

A portion of each metal with a mass of 0.1 g is weighed with an accuracy of ±0.0003 g, was dissolved with heating in 20 cm ofa freshly prepared mixture of nitric and hydrochloric acids is 1:3. After the dissolution of the hitch and stop the allocation of brown fumes of nitrogen oxides the solutions were evaporated to a volume of 3−5 cm, add 20 cmof a hydrochloric acid solution of 1:5. The solutions were cooled and transferred to volumetric flasks with a capacity of 100 cm, the volume was adjusted to the mark with hydrochloric acid 1:5, mix.

The error values of the mass concentration of each element in the solution is ±0.004 mg/cm.

8.1.3 Solutions with mass concentrations of iron, copper, bismuth, lead, cobalt, arsenic and Nickel 1 mg/cm

A portion of each metal with a mass of 0.1 g is weighed with an accuracy of ±0.0003 g, dissolved in 10 cmof nitric acid solution 1:1 under heating. The solutions were incubated on the plate to remove oxides of nitrogen, not boiling, cooled, transferred to volumetric flasks with a capacity of 100 cm, the volume was adjusted to the mark with water and mix.

The error values of the mass concentration of each element in the solution is ±0.004 mg/cm.

8.1.4 Solutions with mass concentrations of manganese, magnesium, titanium, chromium and zinc 1 mg/cm

A portion of each metal with a mass of 0.1 g is weighed with an accuracy of ±0.0003 g, dissolved in 10 cmof hydrochloric acid of 1:1 when heated, not boiling. The solutions were cooled, transferred to volumetric flasks with a capacity of 100 cm, the volume was adjusted to the mark with hydrochloric acid 1:5 and stirred.

The error values of the mass concentration of each element in the solution is ±0.004 mg/cm.

8.1.5 Solution of the mass concentration of silicon of 1 mg/cm

In a glassy carbon crucible with a capacity of 50 cmis placed 1.0 g of sodium hydroxide and a portion of the silicon dioxide () weight 0,214 g, weighed with accuracy of at least ±0,0003 g. the Crucible is placed in an oven and fused at a temperature of (450±50)°C for 20 min. the Crucible is removed from the muffle furnace and cooled to room temperature. In the crucible, add 20 cmof water, heated to dissolve the salts, then cooled, the contents of the crucible transferred to a volumetric flask with a capacity of 100 cm, the volume was adjusted to the mark with water, mixed and immediately transferred to a re-sealable polyethylene, polypropylene or Teflon container.

The error values of the mass concentration of silicon in solution is ±0,003 mg/cm.

The use of other methods of preparation of key solutions and ready-to-use standard or certified solutions subject to obtaining the metrological characteristics are not inferior to those in table 2.

8.2 Preparation of multi-element intermediate solutions

8.2.1 Preparation of intermediate solution containing gold, platinum, palladium, rhodium, selenium, antimony, tellurium

Solution: Pipette taken at 10 cmfundamental solutions of the elements listed and placed in a volumetric flask with a capacity of 100 cm, the volume was adjusted to the mark with hydrochloric acid 1:5 and stirred.

The value of the mass concentration of each of these elements in solution is of 100.0 µg/cm.

The error values of the mass concentration of each element in the solution is ±1.1 µg/cm.

8.2.2 Preparation of intermediate solution containing iron, cobalt, manganese, copper, Nickel, lead, zinc

Solution B: Pipette taken at 10 cmfundamental solutions of the elements listed and placed in a volumetric flask with a capacity of 100 cm, the volume was adjusted to the mark with hydrochloric acid 1:5 and stirred.

The value of the mass concentration of each of these elements in solution is of 100.0 µg/cm.

The error values of the mass concentration of each element in the solution is ±1.1 µg/cm.

8.2.3 Preparation of intermediate solution containing aluminum, bismuth, arsenic, cadmium, magnesium, tin, chromium, titanium

Solution: Pipette taken at 10 cmfundamental solutions of the elements listed and placed in a volumetric flask with a capacity of 100 cm, the volume was adjusted to the mark with hydrochloric acid 1:5 and stirred.

The value of the mass concentration of each of these elements in solution is of 100.0 µg/cm.

The error values of the mass concentration of each element in the solution is ±1.1 µg/cm.

8.2.4 Preparation of intermediate solution containing a silicon

Solution: Pipette select the 10 cmcore solution of silicon and placed in a volumetric flask with a capacity of 100 cm, the volume was adjusted to the mark with hydrochloric acid 1:5, stirred, poured storage in resealable polyethylene, polypropylene or Teflon container.

The value of the mass concentration of silicon in solution is of 100.0 µg/cm.

The error values of mass concentration of elements in solution is ±1.1 µg/cm.

The solution prepared in 8.2, store at room temperature in sealed containers of not more than 1 month.

On the containers of solutions must be pasted label with the indication of the name or symbols of elements mass concentration of elements and the accuracy of its establishment, date of preparation and shelf life of the solution.

8.3 preparation of the calibration samples

Calibration samples for the determination of impurities is prepared from intermediate solutions A, B, C, K, prepared according to 8.2.1−8.2.4.

In a volumetric flask with a capacity of 100 cmpipettes taken aliquote part of the interim solutions according to table 3, the volume was adjusted to the mark with hydrochloric acid 1:5, mix. The «zero» solution (calibration sample TH — 0) is a solution of hydrochloric acid 1:5.


Table 3 — Calibration samples for the determination of impurities

Solutions TH-0, Si-1, Si-2, Si-3, Si-4 is transferred for storage in resealable polyethylene, polypropylene or Teflon container.

Solutions to keep no more than 5 days at room temperature.

Allowed to use other methods for preparing calibration mixtures under the condition of receiving metrological characteristics are not inferior to those in table 2.

9 analysis

9.1 sample Preparation

A laboratory sample of silver is cleaned from surface contamination. For this purpose it is placed in a glass, poured a solution of hydrochloric acid 1:1 so that the entire sample was in solution, and boiled for 5 min. the Solution is decanted and the silver washed 5−6 times with water by means of decantation. The Cup washed with silver is placed in a drying Cabinet and dried for 1 h at a temperature of (100±5)°C.

9.1.1 Preparation of solutions of samples analysed for determination of impurities

If necessary for determination of silicon, among other impurities, it is recommended to conduct all transactions in Teflon or Teflon cookware. If you do not want the determination of silica, is allowed to conduct operations in glass glasses.

To conduct the analysis is performed in two parallel determinations. Hanging silver weight (0,5−2,0) g each are weighed with an accuracy of ±0.0003 g, is placed in glasses with a capacity of 50 cm, add 10 cmof nitric acid solution 1:1 and dissolved for 1 h under the cover when it is heated, not boiling.

After cooling the solution add 10 cmof hydrochloric acid solution 1:1 with constant stirring with a glass rod in order to prevent compaction of the precipitate of silver chloride. Solution and the precipitate was incubated on plate for 1 h under the cover, not boiling and stirring 2−3 times.

To the cooled solution add 5 cmof concentrated hydrochloric acid with vigorous stirring with a glass rod, washed it with water over the beaker and warm the solution for complete coagulation of silver chloride for 1 h under the cover, not boiling.

The cooled solution was filtered in a volumetric flask with a capacity of 25 or 50 cmthrough a pre-washed twice with water double filter «blue ribbon». Washed the precipitate of silver chloride on the filter with hydrochloric acid 1:100 to volume of filtrate in the flask is slightly less than the nominal capacity is adjusted to the mark with water and mix (solution 1).

The received solution 1 is used for determining the content of impurities.

9.1.2 Preparation of solutions of samples analysed for determination of impurities, sosediami with silver chloride

Filter the precipitate of silver chloride on 9.1.1 placed in a beaker with a capacity of 250 cm, add 10 cmsulphuric and nitric acids, kept at room temperature until the cessation of the violent reaction of allocation of oxides of nitrogen, then heated at a maximum temperature of electric heating plate to release dense fumes of sulphuric anhydride. The glass moved to the front of the plate, carefully add 5−7 drops of nitric acid and again heat to release dense fumes of sulphuric anhydride. The operation of adding nitric acid is repeated until complete dissolution of silver chloride. The solution is evaporated to wet salts, is cooled, add with stirring 10 cmof nitric acid, 100 CCof hot water and heated to dissolve the salts. Then to the solution was added 3 cmof hydrochloric acid and immediately filtered into a beaker through filter «blue ribbon», washed 4−5 times with hot hydrochloric acid solution of 1:100 and twice with hot water. The precipitate of silver chloride is washed by decantation 5−6 times a hot solution of hydrochloric acid 1:100, not analyze. The filtrate obtained is evaporated to a volume of 3−5 cm, transferred into a volumetric flask with a capacity of 25 or 50 cmhydrochloric acid solution 1:5, the volume was adjusted to the mark with the same acid solution and mix (solution 2).

The resulting solution of 2 was used to determine the content of impurities.

Combine solutions 1 and 2 for measurements.

Simultaneously with the preparation of samples under the same conditions is carried out at two control («blank») experience for the amendment of the results of the analysis on the purity of the reagents.

9.2 measurements

9.2.1 preparing the spectrometer to work and work on the device carried out according to the instruction manual of the spectrometer. The program of measurements enter values of mass concentrations of the calibration samples, the wavelengths of the analytical lines, the point of correction of the background plasma parameters.

Recommended wavelengths of the analytical lines given in table 4.


Table 4 — wavelengths of the analytical lines

The use of other lines subject to obtaining the metrological characteristics are not inferior to those in table 2.

9.2.2 Calibration samples successively introduced into the plasma and measure the intensity of the analytical lines of the determined elements minus background (the intensity of the radiation spectrum near the analytical line of the designated element). For each solution perform three measurements and calculate the average value of intensity.

The calibration characteristics is obtained in the coordinates (, ) where is the mass concentration of the determined element in the solution for calibration, in µg/cm, the value of the intensity of the analytical line of the element minus the background.

9.2.3 Then the plasma is injected solutions of control experiments and analyze samples. For each solution perform three measurements of the intensity of analytical lines of the determined elements (with background subtracted) and calculated average values. Using the calibration characteristics are the value of the mass concentration of element in solution of the sample and the reference experiment.

10 assessment of the admissibility of the results of parallel measurements and obtaining the final result of the analysis

10.1 Mass fraction of the element in % is calculated by the formula

, (2)

where is the value of the mass concentration of the analyzed element in the sample solution, obtained by the calibration feature, µg/cm;

 — the arithmetic mean value of two results of parallel measurements of the mass concentration of element in solution in the reference experiment, µ g/cm;

 — the volume of analyzed sample solution, cm;

 — the weight of the portion of the sample,

The result of a single analysis for each element is the sum of the mass fraction, determined from solutions 1 and 2.

10.2 acceptance of the results of parallel measurements is estimated according to GOST R ISO 5725−6 by comparing the absolute discrepancy of the two results of parallel measurements with a limit value of the frequency of occurrence given in table 2.

If not exceed , two parallel definitions recognize acceptable and for the final result of the analysis is to take their arithmetic mean value.

If exceeds , then spend another two parallel definitions. If the range of the four results of the parallel definition (a) does not exceed the critical range for the 4, , the final result of the analysis taking the arithmetic mean of the four results of parallel measurements.

The critical range is calculated by the formula

, (3)

where the 3.6 — the ratio of the critical range for four parallel measurements;

 — standard deviation of repeatability, the values of which are given in table 2.

If the range of the four results of parallel measurements exceeds , the final result of the analysis taking the median of four results of parallel measurements.

11 Making measurements

The result of the analysis (measurements) are in the form:

and , of 0.95

where  — mass fraction of the element, %;

 — feature measurement uncertainty of the mass fraction of the element at 0,95. The values given in table 2.

This numerical value analysis result is rounded up to discharge, which recorded the last significant figure errors.

12 Control of accuracy of analysis results

12.1 Control of intermediate precision and reproducibility

When monitoring intermediate precision (variable factors of the operator and time) is the absolute value of the difference between two results of analysis of the same sample obtained by different operators using the same equipment on different days, should not exceed the limit of intermediate precision specified in table 2.

Under the control of the reproducibility of the absolute value of the difference of the two results of the analysis of the same samples obtained by two laboratories in accordance with the requirements of this standard must not exceed the limit of reproducibility shown in table 2.

12.2 verification of correct

The checking is carried out by the analysis of samples for monitoring (QA) and control samples.

When checking the absolute value of the difference between the analysis result and the reference value of the mass fraction of element-impurities in the sample for the control or control sample should not exceed the critical value .

The critical value is calculated by the formula

, (4)

where  — error of the reference value of the mass fraction of element-impurities in the sample for the control or control sample, %;

 — the indicator of the accuracy of the analysis result corresponding to the reference value of the mass fraction of element-impurities in OK or control sample, %. The values given in table 2.

Bibliography

________________

* The document is not given. For additional information, please refer to the link. — Note the manufacturer’s database.

__________________________________________________________________________
UDC 669.214; 543.06; 543.42; 311.214 OKS 77.120.99

Keywords: refined silver, silver bullion, impurities, methods of analysis, atomic emission with inductively coupled plasma method of analysis, control samples, control of accuracy of analysis results, accuracy, precision