GOST 15027.7-77
GOST 15027.7−77 Bronze without tin. Methods for determination of lead (with Amendments No. 1, 2)
GOST 15027.7−77
Group B59
INTERSTATE STANDARD
BRONZE WITHOUT TIN
Methods for determination of lead
Non-tin bronze.
Methods for the determination of lead
AXTU 1709
Date of introduction 1979−01−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from
3. REPLACE GOST 15027.7−69
4. The standard fully complies ST SEV 1530−79. Standard corresponds to ISO 4749−84 in part of bronze without tin
5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
Section number, paragraph |
| GOST 493−79 |
Chapeau |
| GOST 614−97 |
Chapeau |
| GOST 2062−77 |
2.2, 4.2, 6.2 |
| GOST 3117−78 |
2.2 |
| GOST 3118−77 |
2.2, 5.2, 6.2, 7.2 |
| GOST 3760−79 |
4.2, 5.2, 6.2 |
| GOST 3773−72 |
5.2 |
| GOST 3778−98 |
2.2, 4.2, 5.2, 6.2, 7.2 |
| GOST 4109−79 |
2.2, 4.2. 6.2 |
| GOST 4147−74 |
4.2 |
| GOST 4166−76 |
5.2 |
| GOST 4204−77 |
2.2 |
| GOST 4207−75 |
2.2 |
| GOST 4233−77 |
2.2 |
| GOST 4328−77 |
5.2 |
| GOST 4461−77 |
2.2, 3.2, 4.2, 5.2, 6.2, 7.2 |
| GOST 4658−73 |
4.2 |
| GOST 5817−77 |
5.2 |
| GOST 6552−80 |
4.2 |
| GOST 6563−75 |
3.2 |
| GOST 8864−71 |
5.2 |
| GOST 9293−74 |
4.2 |
| GOST 10434−82 |
4.2 |
| GOST 10484−78 |
6.2, 7.2 |
| GOST 10652−73 |
2.2 |
| GOST 10929−76 |
6.2 |
| GOST 14162−79 |
4.2 |
| GOST 14261−77 |
4.2 |
| GOST 18175−78 |
Chapeau |
| GOST 18300−87 |
2.2, 5.2 |
| GOST 25086−87 |
1.1, 2.4.2 b, 4.4.2 b, 7.4.4 |
6. Limitation of actions taken by Protocol No. 3−93 Interstate Council for standardization, Metrology and certification (ICS 5−6-93)
7. EDITION with Amendments No. 1, 2 approved in February 1983, March 1988 (IUS 6−83, 6−88)
This standard establishes titrimetric chelatometric method for the determination of lead (with a mass fraction of lead from 0.8% to 65%), gravimetric electrolytic method for the determination of lead (with a mass fraction of lead from 0.8% to 2.5%), a polarographic method for the determination of lead (with a mass fraction of lead from 0.001% to 0.6%), extraction-photometric method for the determination of lead (with a mass fraction of lead from 0.001% to 0.5%) and atomic absorption method for the determination of lead (with a mass fraction of lead from 0.002% to 0.02% and more than 0.02% to 12%) in tin bronze according to GOST 18175, GOST and GOST 614 493.
(Changed edition, Rev. N 1, 2).
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 25086 with the addition of sec. 1 GOST 15027.1.
(Changed edition, Rev. N 1, 2).
2. TITRIMETRIC CHELATOMETRIC METHOD FOR THE DETERMINATION OF LEAD
2.1. The essence of the method
The method is based on titration of lead acetate at a pH of 5.4−6.0 mm solution of Trilon B in the presence kylinalove orange until the color changes from purple to yellow.
2.2. Apparatus, reagents and solutions
Sulfuric acid according to GOST 4204, diluted 1:1 and 1:50.
Nitric acid according to GOST 4461, diluted 1:1.
Hydrochloric acid according to GOST 3118.
A mixture of nitric and hydrochloric acids; prepared as follows: one volume of nitric acid mixed with three volumes of hydrochloric acid.
Bromine according to GOST 4109.
Bromatologia acid according to GOST 2062.
Mix to dissolve, freshly made: nine volumes bromatological acid is mixed with one volume of bromine.
Rectified ethyl alcohol according to GOST 18300.
Potassium ferrocyanide according to GOST 4207, a solution of 30 g/DM.
Ammonium acetate according to GOST 3117, a solution of 250 g/DM.
Lead brands S0 GOST 3778.
Standard solution of lead; prepared as follows: 1 g of lead is dissolved by heating in a beaker with a capacity of 250 cmto 20 cm
of nitric acid. Remove the oxides of nitrogen by boiling, cool and transfer the solution into volumetric flask with a capacity of 100 cm
, and then topped to the mark with water and mix.
1 cmof the solution contains 0.01 g of lead.
Indicator kylinalove orange, the drug is mixed with sodium chloride in a ratio of 1:100, well pounded.
Sodium chloride according to GOST 4233.
Salt is the disodium Ethylenediamine-N, N, N', N'-tetraoxane acid 2-water (Trilon B) according to GOST 10652, a solution of 0.05 mol/DM, is prepared as follows: 9,305 g Trilon B dissolved in 500 cm
of water when heated, transferred to a volumetric flask with a capacity of 1 DM
and topped to the mark with water.
The installation of the titer of the solution Trilon B
5 cmstandard solution of lead was placed in a beaker with a capacity of 250 cm
, 40 cm poured
sulphuric acid, diluted 1:1, and evaporated until a white smoke of sulfuric acid. The solution was cooled, washed walls of glass with water and repeat the evaporation until a white smoke of sulfuric acid. The solution was cooled, poured 150 cm
of water and heated to boiling, again cooled, poured 40 cm
ethanol and left for 4 h. Further analysis are as indicated in claim 2.3.
The titer of the solution Trilon B (), expressed in grams of lead per 1 cm
of a solution, calculated by the formula
where is the mass of the lead sample, g;
— volume of solution Trilon B, spent on titration, sm
.
2.3. Analysis
2.3.1. For alloys with a mass fraction of tin is less than 0.05%
Linkage of bronze depending on the mass fraction of lead are given in table.1.
Table 1
| Mass fraction of lead, % |
The mass of charge, g |
| From 0.8 to 5 |
2 |
| SV. 5 «20 |
1 |
| «20» 30 |
0,5 |
| «30» 65 |
0,1 |
The weight of bronze is placed in a beaker with a capacity of 300 cm, cover with a watch glass and dissolved in 15 cm
of the mixture of acids when heated. After dissolution of the alloy wash glass, poured 40 cm
of sulphuric acid diluted 1:1, and evaporated until a white smoke of sulfuric acid. The solution was cooled, the side of the Cup washed with water and evaporated again until a white smoke of sulfuric acid. The residue is cooled, poured 150 cm
of water, heated to boiling and cooled. Then pour 40 cm
ethanol and left for 4 h. the Separated precipitate of lead sulphate filtered off on a tight filter, the beaker rinsed with sulfuric acid, diluted 1:50, and the precipitate washed with the same acid until the complete removal of bivalent copper (test with potassium ferrocyanide), and then two or three times with water. The filter with precipitate was placed in a beaker, in which was conducted the deposition. Pour 15 cm
of a solution of acetate of ammonia, heated to boiling and boiled for 2 min.
The solution is decanted into a flask with a capacity of 250 cm. The glass filter is poured twice 30 cm
of hot water, each time pouring the solution into the same flask. Back in the beaker with filter pour 15 cm
of ammonium acetate solution and twice repeat the washing water.
The resulting solution is added at the tip of a spatula mix kylinalove orange with sodium chloride and titrated with a solution of Trilon B to a transition of a purple color in geltu
Yu.
2.1−2.3.1. (Changed edition, Rev. N 1).
2.3.2. For alloys with a mass fraction of tin in excess of 0.05%
Weighed bronze (see table.1) is placed in a beaker with capacity of 500 cmand dissolved in 20 cm
of the mixture for dissolution, after the dissolution sample solution is gently evaporated to dryness. Evaporation with 15 cm
of the mixture to dissolve is repeated twice, each time bringing the sample to dry residue. To the residue add 10−20 cm
of sulphuric acid diluted 1:1, and the solution is evaporated until a white smoke of sulfuric acid. Then do as stated in claim
(Added, Rev. N 1).
2.4. Processing of the results
2.4.1. Mass fraction of lead (a) percentage calculated by the formula
where — volume of solution Trilon B, used for titration, cm
;
the titer of the solution Trilon B on lead, g/cm
;
— the weight of the portion,
2.4.2. The absolute discrepancies in the results of parallel measurements (the rate of convergence) must not exceed the permissible values given in table.2.
Table 2
| Mass fraction of lead, % |
|
|
| From 0.001 to 0.002 |
0,0005 | 0,001 |
| SV. Of 0.002 «to 0.005 |
0,0008 | 0,002 |
| «To 0.005» 0.010 is |
0,001 | 0,002 |
| «Of 0.010» to 0.025 |
0,002 | 0,005 |
| «0,025» 0,050 |
0,004 | 0,01 |
| «0,050» 0,10 |
0,005 | 0,01 |
| «To 0.10» to 0.25 |
0,01 | 0,02 |
| «0,25» 0,5 |
0,02 | 0,05 |
| «0.5 to 1.0 |
0,06 | 0,1 |
| «Of 1.0» to 4.0 |
0,08 | 0,2 |
| «A 4.0» to 7.0 |
0,12 | 0,3 |
| «To 7.0» to 9.0 |
0,15 | 0,4 |
| «To 9.0» 20 |
0,20 | 0,5 |
| «20» 30 |
0,25 | 0,6 |
| «30» 40 |
0,30 | 0,7 |
| «40» 65 |
0,40 | 0,9 |
(Changed edition, Rev. N 2).
2.4.2. The absolute discrepancies of the analysis results obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (a measure of reproducibility) shall not exceed the values given in table.2.
2.4.2 b. Control of accuracy of analysis results
Control of accuracy of analysis results is carried out according to State standard samples without tin bronzes, certified in the prescribed manner, or by comparison of the results studied by titrimetric and gravimetric or atomic absorption methods or by a method of additives in accordance with GOST 25086.
2.4.2 a, 2.4.2 b. (Added, Rev. N 2).
2.4.3. The differences in the assessment of the quality of bronze used this method.
3. GRAVIMETRIC ELECTROLYTIC METHOD FOR THE DETERMINATION OF LEAD
3.1. The essence of the method
The method is based on the release of lead electrolytically and weighing the separated precipitate of dioxide of lead.
3.2. Apparatus, reagents and solutions
Installation for electrolysis with a platinum mesh electrode according to GOST 6563.
Nitric acid according to GOST 4461, diluted 1:1.
The sulfamic acid.
3.3. Analysis
The weight of bronze weighing 0.5 g were placed in a glass with a capacity of 250 cm, add 15 cm
of nitric acid, diluted 1:1, cover with a watch glass and dissolve without heating, and then by heating. Watch glass and walls of beaker is washed with water, the solution heated to boiling, add 0.5 g of sulfamic acid, dilute with water to 150 cm
and produce copper and lead by electrolysis, using platinum mesh electrodes, at a current of 1.5 to 2.0 and stirring. The glass electrolyte must be covered by a watch glass.
After 30 min after the start of the electrolysis removed the glass, washed it with water and continue the electrolysis for another 15 minutes, If after that svezhemorozhenoj in the solution part of the anode is not allocated sediment, the electrolysis is complete. Without turning off the current, quickly remove the beaker with the electrolyte and washed electrodes, alternately substituting the three cups with distilled water.
The anode and the precipitate of dioxide of lead dried at 160−170 °C to constant weight, cooled and weighed.
3.4. Processing of the results
3.4.1. Mass fraction of lead (a) percentage calculated by the formula
where is the mass of the precipitate of lead dioxide evolved at the anode, g;
0,8661 — the ratio of dioxide of lead, lead; — the weight of the portion,
3.4.2. The absolute discrepancies in the results of parallel measurements (the rate of convergence) must not exceed the permissible values given in table.2.
(Changed edition, Rev. N 2).
3.4.3. The absolute discrepancies of the analysis results obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (a measure of reproducibility) shall not exceed the values given in table.2.
3.4.4. Control of accuracy of analysis results
Control of accuracy of analysis results is carried out according to claim 2.4.2 b.
3.4.3,
4. POLAROGRAPHIC METHOD FOR THE DETERMINATION OF LEAD
4.1. The essence of the method
The method is based on preliminary separation of lead from primary metals by coprecipitation with ferric hydroxide in ammoniacal solution with subsequent determination of lead by a polarographic method.
4.2. Apparatus, reagents and solutions
Polarograph types ACCORDING 5122, PPT-1 or similar type.
The polarographic cell, made of glass, with external electrode (saturated calomel electrode) and mercury-drip cathode.
Hydrochloric acid according to GOST 14261 and diluted 1:1 and 5% solution.
Nitric acid according to GOST 4461, diluted 1:1.
Sulfuric acid according to GOST 14162.
Hydrofluoric acid according to GOST 10434.
Perchloric acid, h. e. a.
Bromatologia acid according to GOST 2062.
Bromine according to GOST 4109.
Orthophosphoric acid according to GOST 6552 and a solution of 1 mol/DM.
Mix to dissolve the freshly prepared nine volumes bromatological acid is mixed with one volume of bromine.
Ammonia water according to GOST 3760 and 2% solution.
Iron chloride according to GOST 4147, a solution of 10 g/DMin a 5% strength solution of hydrochloric acid.
Lead brands S0 GOST 3778.
Standard solutions of lead
Solution A, prepared as follows: 0.1 g of lead is dissolved by heating in 30 cmof nitric acid is removed by boiling the oxides of nitrogen, cooled, poured 50 cm
of water, transfer the solution into a measuring flask with a capacity of 1 DM
, made up to the mark with water and mix.
1 cmof the solution contains 0.0001 g of lead.
Solution B is prepared as follows: 10 cmof solution A is placed in a volumetric flask with a capacity of 100 cm
, add 2 cm
of concentrated hydrochloric acid, made up to the mark with water and mix.
1 cmof solution B has the 0.00001 g of lead. Solution B is prepared immediately before use.
Mercury brands r0 according to GOST 4658, dehydrated.
Nitrogen gas according to GOST 92
93.
4.3. Analysis
4.3.1. For all bronzes except the siliceous
A portion of the alloy (tab.4) is placed in a beaker with a capacity of 250 cm, cover with a watch glass and gently dissolved in 20 cm
of the mixture for dissolution. With incomplete dissolution in the beaker was added dropwise bromine. Poured to a solution of 20 cm
of perchloric acid and evaporate the solution to lighten and the appearance of dense white smoke of perchloric acid (total volume, the remaining solution should not exceed 5 cm
). Cool the beaker, wash the side of the Cup a small amount of water, heated to dissolve the salts and add water up to 100−150 cm
.
For silicon bronze alloy sample (see table.4) is placed in a platinum Cup, add 20 cmof nitric acid and 5 cm
hydrofluoric acid and dissolved by heating. After dissolving, the solution was evaporated to dryness. Add 10 cm
of concentrated nitric acid and repeat the evaporation of 3−4. Add 50 cm
water and 5 cm
of nitric acid, diluted 1:1, and dissolved salts, when heated. The contents of the Cup are transferred into the beaker, diluting the solution with water to 100−150 cm
.
Table 4
| Mass fraction of lead, % | The mass of charge, g | Polarographically the volume of solution, cm |
| From 0.001 to 0.003 |
1 | 40 |
| SV. Of 0.003 «to 0.01 |
1 | 20 |
| «0,01» 0,025 |
1 | 10 |
| «Of 0.025» to 0.05 |
0,5 | 5 |
| «0,05» 0,1 |
0,5 | 2 |
| «To 0.1» to 0.6 |
0,1 | 10 |
(Changed edition, Rev. N 1).
4.3.3. To the obtained solution (see PP.4.3.1 and 4.3.2) pour 1 cmof solution of ferric chloride (at a mass fraction of iron in the bronze less than 0.5%) and ammonia to form a dark blue complex of copper and beyond that another 5 cm
of ammonia solution and maintained at 60−70 °C for 29 min. the Precipitate was filtered off on a filter of medium density. The glass and the filter cake was washed 3−4 times with hot 1% solution of ammonia. The funnel with the precipitate was placed on glass, which made the deposition, the precipitate was dissolved in 20 cm
of hot hydrochloric acid, diluted 1:1, adding a few drops of hydrogen peroxide in the presence of manganese bronze.
The filter is washed with 30 cmof hot water, the solution was diluted to a 125−150 cm
and repeat the precipitation.
After three perioadele the filter cake is dissolved in 5 cmof perchloric acid. Dilute the solution with water to 25 cm
, flow 14 cm
of concentrated phosphoric acid, transferred to a volumetric flask with a capacity of 50 cm
, adjusted solution to the mark with water and mix.
Simultaneously with the determination of lead in bronze spend control experience with all reagents according to the above methods
ke.
4.3.4. Taken from the flask aliquot part of the solution (see table.4) and transferred to a polarographic cell, previously washed with a solution of 1 mol/lphosphoric acid. The solution in the cell is degassed flowing nitrogen for 5−7 min, stop stirring and remove the cathodic polarization curve in the voltage range from minus 0.2 to minus 0.7 V. the Peak recovery of lead observed in the field minus 0,45 V. the Sensitivity of the recording instrument is chosen such that the peak of lead was at least 15 mm.
4.3.5. Lead find by the method of standard additions. Aliquot part of the solution A or b, depending on the content of lead, added to polarographically solution, stirred the solution 4 min and further analysis as lead in determining the content of lead in test solution (see p.4.3.4).
The value of a standard additive chosen such that the peak height of lead after introduction of the additive increased 1.5−2 times.
4.4. Processing of the results
4.4.1. Mass fraction of lead (a) percentage calculated by the formula
where is the peak height of lead in polarography solution in the reference experiment, mm.
the peak height of lead in polarography of test solution, mm;
— the height of the peak of the lead after the introduction of standard additives, mm;
— the volume of standard addition, cm
;
— concentration of standard solution, g/cm
;
— the weight of alloy taken for polarography,
G.
4.4.2. The absolute discrepancies in the results of parallel measurements (the rate of convergence) must not exceed the permissible values given in table.2.
(Changed edition, Rev. N 2).
4.4.2. The absolute discrepancies of the analysis results obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (a measure of reproducibility) shall not exceed the values given in table.2.
4.4.2 b. Control of accuracy of analysis results
Control of accuracy of analysis results is carried out according to State standard samples without tin bronzes, certified in the prescribed manner, comparison of the results of the analysis obtained of the polarographic and photometric methods or by a method of additives in accordance with GOST 25086.
4.4.2 a, 4.4.2 b. (Added, Rev. N 2).
4.4.3. The differences in the assessment of the quality of bronze used polarographic method.
5. THE PHOTOMETRIC METHOD FOR THE DETERMINATION OF LEAD
5.1. The essence of the method
The method is based on extraction of lead from alkaline medium by chloroform in the form of diethyldithiocarbaminate, the substitution of lead with copper, by shaking the extract with an excess of an aqueous solution of copper sulphate and measuring the optical density of the obtained chloroform solution diethyldithiocarbaminate copper.
5.2. Apparatus, reagents and solutions
Photoelectrocolorimeter or spectrophotometer.
Tartaric acid according to GOST 5817, a solution of 400 g/DM.
Hydrochloric acid according to GOST 3118, diluted 1:1.
Nitric acid according to GOST 4461 and diluted 1:1.
Sodium hydroxide according to GOST 4328, a solution of 500 g/DM.
Ammonia water according to GOST 3760 and diluted 1:50.
Diethyldithiocarbaminate sodium GOST 8864, water and chloroform solutions of 10 g/DM.
Phenolphthalein, solution at 10 g/lin ethanol.
Rectified ethyl alcohol according to GOST 18300.
Copper sulfate according to normative-technical documentation, solution 50 g/DM.
Chloroform.
Lead at GOST brand 3778 S0.
Standard solutions of lead.
Solution A, prepared as follows: 0.1 g of lead dissolved in 20 cmof nitric acid, diluted 1:1, when heated. After removal of oxides of nitrogen by boiling the solution transferred to a volumetric flask with a capacity of 1 DM
, made up to the mark with water and mix.
1 cmof the solution contains 0.0001 g of lead.
Solution B is prepared as follows: transfer 10 cmof solution A in a volumetric flask with a capacity of 100 cm
, made up to the mark with water and mix.
1 cmof solution B has the 0.00001 g of lead.
Ammonium chloride according to GOST 3773.
Sodium sulphate anhydrous according to GOST 4166.
Iron, standard sample No. 126 (low carbon steel).
The solution of nitrate of iron; prepared as follows: 1,005 g WITH N 126 dissolved in 15 cmof concentrated nitric acid followed by dilution with water to 1 DM
.
1 cmof the solution contains 0.001 g of iron.
(Revised edition, Edit
. N 1).
5.3. Analysis
5.3.1. For all bronzes except the siliceous
A sample of alloy weighing 1 g is placed in a beaker with a capacity of 250 cm, and dissolved in 20 cm
of nitric acid, diluted 1:1, and 2 cm
of hydrochloric acid. The solution is diluted with water to 150 cm
, add 5 g of ammonium chloride and 30 cm
of a solution of nitrate of iron (for alloys with a mass fraction of iron less than 0.5%), heated to 80−90 °C and ammonia is added to the transfer of all the copper in the soluble ammonia complex. Upset give koagulirovat in a warm place for 20−30 min, after which the precipitate was filtered off on a medium density filter and washed free of copper with hot solution of ammonia, diluted 1:50. The precipitate is dissolved in 10 cm
of hot nitric acid diluted 1:1, and repeat the precipitation of the hydroxide and the dissolution to the disappearance of copper ions in the filtrate (sample diethyldithiocarbaminate sodium in chloroform.
The precipitate is dissolved in 10 cmof hot nitric acid diluted 1:1 in a glass, which made the deposition, and boil to remove oxides of nitrogen. For the mass concentration of lead is less than 0.01% to the extraction using the full solution with the mass fraction of lead more than 0.01% and the solution transferred to a volumetric flask with a capacity of 250 cm
, made up to the mark with water and mix. Aliquot part of the solution is 25 cm
(with mass fraction of lead from 0.01% to 0.05%), 10 cm
(with a mass fraction of lead from 0.05% to 0.2%) or 5 cm
(when the mass fraction of lead from 0.2% to 0.5%) is transferred to a separatory funnel with a capacity of 250 cm
. The solution in the funnel is diluted with water to 100 cm
, add 15 cm
of a solution of tartaric acid, neutralized with sodium hydroxide solution to phenolphthalein before occurrence of pink coloring and on top of this add another 3−5 cm
of sodium hydroxide solution. Then add 5 cm
of an aqueous solution of sodium diethyldithiocarbaminate, 15 cm
of chloroform, and extracted the lead in the form of diethyldithiocarbaminate, shaking 5 min, the Lower chloroform layer is drained into another separatory funnel so that the funnel tap did not get the aqueous solution. To the remaining aqueous phase add 5 cm
of chloroform and shaken for 3 min Chloroform layer is attached to the main extract. Separately in a glass make 1 cm
of a solution of tartaric acid, poured thereto 10 cm
of water, basified with sodium hydroxide solution until the alkaline reaction to phenolphthalein and beyond that another add 2−3 drops of sodium hydroxide solution. This solution is poured into the separating funnel containing the combined extracts and shaken for 3 min Chloroform layer is drained into a third separating funnel, add 20 cm
of a solution of copper sulphate and shake for 5 min. Painted the chloroform layer was transferred into a measuring flask with a capacity of 25 cm
, which has added 0.2 g of sodium sulfate. The chloroform solution in the volumetric flask, add chloroform to the mark, and measure optical density of the solution on the spectrophotometer in a cuvette length of 1 cm at a wavelength of 430 nm or photoelectrocolorimeter in a ditch with a length of 1 or 2 cm with a blue filter. The comparison solution is a Koh solution
— controlling experience.
5.3.2. For silicon bronze
The sample of bronze with a weight of 1 g was placed in a platinum Cup and dissolved in 20 cmof nitric acid, diluted 1:1, and 5 cm
hydrofluoric acid when heated. After dissolving, the solution was evaporated to dryness. Add 10 cm
of concentrated nitric acid and repeat the evaporation of 3−4. Add 50 cm
water and 5 cm
of nitric acid, diluted 1:1, and dissolved salts when heated. The contents of the Cup was transferred to a glass, diluting with water up to 150 cm
, and further analysis are as indicated in claim
5.3.3. Construction of calibration curve
In a separating funnel with a capacity of 250 cmmake 0; 1,0; 2,0; 3,0; 5,0; 7,0 and 10.0 cm
standard solution B, dilute with water to 100 cm
, is added to 15 cm
of a solution of tartaric acid and further analysis are as indicated in claim
5.4. Processing of the results
5.4.1. Mass fraction of lead (a) percentage calculated by the formula
where the amount of lead was found in the calibration schedule g;
— the weight of the portion,
5.4.2. The absolute discrepancies in the results of parallel measurements (the rate of convergence) must not exceed the permissible values given in table.2.
(Changed edition, Rev. N 2).
5.4.3. The absolute discrepancies of the analysis results obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (a measure of reproducibility) shall not exceed the values given in table.2.
5.4.4. Control of accuracy of analysis results
Control of accuracy of analysis results is carried out according to claim 4.4.2 b.
5.4.3,
6. ATOMIC ABSORPTION METHOD for the DETERMINATION of LEAD (WITH a MASS FRACTION of LEAD from 0.002% to 0.2%)
6.1. The essence of the method
The method is based on measurement of light absorption by atoms of lead, formed by the introduction of the analyzed solution in the flame acetylene-air after pre-selection of lead by coprecipitation with ferric hydroxide.
6.2. Apparatus, reagents and solutions
Atomic absorption spectrometer with a radiation source for lead.
Nitric acid according to GOST 4461, diluted 1:1.
Hydrochloric acid according to GOST 3118 and diluted 1:1, 1:3 and a solution of 2 mol/DM.
Hydrofluoric acid according to GOST 10484.
The acid chloride.
Bromatologia acid according to GOST 2062.
Bromine according to GOST 4109.
Mix to dissolve, freshly made: nine volumes bromatological acid is mixed with one volume of bromine.
Ammonia water according to GOST 3760 and diluted 1:19.
Hydrogen peroxide according to GOST 10929.
Iron chloride, solution, 15 g/lin hydrochloric acid, diluted 1:3.
Aluminium metallic, with a mass fraction of lead is less than 0.001%.
Aluminium chloride solution 50 g/l; prepared as follows: 5 g of aluminium is dissolved in 150 cm
of hydrochloric acid diluted 1:1 with the addition of a few drops of hydrogen peroxide. The solution was evaporated until beginning crystallization of aluminum chloride, cooled, transferred to a volumetric flask with a capacity of 100 cm
and top up with water to the mark.
Lead according to GOST 3778 with a mass fraction of lead not less than 99.9%.
Standard solutions of lead.
Solution A, prepared as follows: 0.5 g of lead is dissolved by heating in 20 cmof nitric acid, diluted 1:1, the solution was cooled, transferred to a measuring flask with volume capacity of 1000 cm
and top up with water to the mark.
1 cmof the solution contains 0.0005 g of lead.
Solution B is prepared as follows: 20 cmsolution And placed in a volumetric flask with a capacity of 100 cm
, add 10 cm
solution of 2 mol/DM
of hydrochloric acid and add water to the mark.
1 cmof a solution contains 0.0001 g
lead.
6.3. Analysis
6.3.1. For bronzes with a mass fraction of tin, silicon and aluminum is less than 0.05%
The weight of bronze weighing 2 g were placed in a glass with a capacity of 250 cmand dissolved by heating in 20 cm
of nitric acid, diluted 1:1. Nitrogen oxides are removed by boiling and the solution diluted with water to a volume of 150 cm
. Add 5 cm
of a solution of ferric chloride (bronze containing iron as an alloying component, should not be added to a solution of ferric chloride), the solution is heated to a temperature of 80−90 °C and ammonia is added to complete the transition of copper and Nickel in ammoniacal systems. The precipitate of hydroxide is allowed to stand for 10 min at 60 °C, filtered on a medium density filter and washed with hot ammonia solution, diluted 1:19 for the removal of copper and Nickel, and then three times with hot water.
The deployed filter washed with hot water into a glass, which conducted the deposition, the filter is washed with 10 cmof hot hydrochloric acid solution, diluted 1:1 and then with water. The washed filter is discarded and the solution was evaporated to a volume of 5 cm
. The solution was cooled, added to 10 cm
of water, transferred to a volumetric flask with a capacity of 25 cm
and top up with water to the mark.
Measure the atomic absorption of lead in the flame of acetylene-air at a wavelength is 283.3 nm parallel to the calibration solutions
I.
6.3.2. For bronzes, with a mass fraction of tin in excess of 0.05%
The weight of bronze weighing 2 g were placed in a glass with a capacity of 250 cm, adding 25 cm
of the mixture to dissolve and gently heated until complete dissolution. Then add 10 cm
of perchloric acid and evaporated to a volume of 4 cm
. The residue was cooled, added to 30 cm
of water and heated to dissolve the salts. The solution is diluted with water to a volume of 150 cm
, add 5 cm
of a solution of ferric chloride, heated to a temperature of 80−90 °C, ammonia is added to complete the transition of copper ammonia complex and further analysis is carried out as specified in clause 6.3.1
.
6.3.3. For bronzes with a mass fraction of silicon in excess of 0.05%
The weight of bronze weighing 2 g was placed in a platinum Cup and dissolved by heating in 20 cmof nitric acid, diluted 1:1, and 2 cm
hydrofluoric acid. Then add 10 cm
of perchloric acid and heated until the appearance of dense white fumes. The residue was cooled, added to 30 cm
of water and heated to dissolve the salts. The solution was transferred to a beaker with a capacity of 250 cm
, is diluted with water to a volume of 150 cm
, add 5 cm
of a solution of ferric chloride, heated to a temperature of 80−90 °C, ammonia is added to complete the transition of copper ammonia complex and further analysis is carried out as specified in clause 6.3.1
.
6.3.4. For bronzes containing aluminum as a component
The weight of bronze weighing 2 g were placed in a glass with a capacity of 250 cmand dissolved by heating in 20 cm
of nitric acid, diluted 1:1, with the addition of a few drops of hydrochloric acid. Nitrogen oxides are removed by boiling and the solution diluted with water to a volume of 150 cm
. The solution is heated to a temperature of 80−90 °C, ammonia is added to complete the transition of copper ammonia complex and further analysis is carried out as specified in clause
6.3.5. Construction of calibration curve
6.3.5.1. For bronzes that do not contain aluminium as a component
In six of the seven volumetric flasks with a capacity of 100 cmis placed 1,0; 2,5; 5,0; 10,0; 15,0 and 20.0 cm
standard solution B lead. To each flask add 10 cm
solution of 2 mol/DM
of hydrochloric acid and add water to the mark.
Measure the atomic absorption of lead as specified in claim
6.3.5.2. For bronzes containing aluminum as a component
In seven volumetric flasks with a capacity of 50 cmis placed depending on the aluminum content in the sample from 2 to 10 cm
of a solution of aluminum chloride and in six of them add 0,5; 1,25; 2,5; 5,0; 7,5; 10,0 cm
standard solution B lead, 5 cm
solution 2 mol/DM
of hydrochloric acid and add water to the mark.
Measure the atomic absorption of lead as specified in claim
6.4. Processing of the results
6.4.1. Mass fraction of lead (a) percentage calculated by the formula
where is the concentration of lead was found in the calibration schedule, g/cm
;
— the volume of the final sample solution, cm
;
— the weight of the portion,
6.4.2. The absolute discrepancies in the results of parallel measurements (the rate of convergence) must not exceed the permissible values given in table.2.
(Changed edition, Rev. N 2).
6.4.3. The absolute discrepancies of the analysis results obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (a measure of reproducibility) shall not exceed the values given in table.2.
6.4.4. Control of accuracy of analysis results
Control of accuracy of analysis results is carried out according to claim 4.4.2 b.
6.4.3,
7. ATOMIC ABSORPTION METHOD for the DETERMINATION of LEAD (WITH a MASS FRACTION of LEAD from 0.02% to 12%)
7.1. The essence of the method
The method is based on measuring the absorption of light by atoms of lead, formed by the introduction of the analyzed solution in the flame acetylene-air.
7.2. Apparatus, reagents and solutions
Atomic absorption spectrometer with a radiation source for lead.
Nitric acid according to GOST 4461 and diluted 1:1.
Hydrochloric acid according to GOST 3118, solutions 2 and 1 mol/DM.
A mixture of acids, is prepared as follows: the amount of nitric acid mixed with three volumes of hydrochloric acid.
Hydrofluoric acid according to GOST 10484.
Perchloric acid, h. e. a.
Lead according to GOST 3778 with a mass fraction of lead not less than 99.9%.
Standard solutions of lead
Solution A, prepared as follows: 0.5 g of lead is dissolved by heating in 20 cmof nitric acid, diluted 1:1, the solution was cooled, transferred to a measuring flask with volume capacity of 1000 cm
and top up with water to the mark.
1 cmof the solution contains 0.0005 g of lead.
Solution B is prepared as follows: 20 cmsolution And transferred to a volumetric flask with a capacity of 100 cm
, add 10 cm
solution of 2 mol/DM
of hydrochloric acid and add water to the mark.
1 cmof a solution contains 0.0001 g pig
CA.
7.3. Analysis
7.3.1. For bronzes with a mass fraction of tin and silicon up to 0.05%
A portion of the bronze mass, given in table.7, is placed in a beaker with a capacity of 250 cmand dissolved by heating in 10 cm
of nitric acid, diluted 1:1. The solution was cooled, transferred to a volumetric flask with a capacity of 100 cm
and top up with water to the mark.
Table 7
| Mass fraction of lead, % | The mass of charge, g | The volume aliquote part of the solution, cm |
The volume of 2 mol/DM |
The volume of sample solution after dilution, see |
| From 0.02 to 1 |
1 | - | - | 100 |
| SV. 1 «6 |
1 | 10 | 10 | 100 |
| «6» 12 |
0,5 | 10 | 25 | 250 |
When the mass fraction of lead more than 1% 10 cmof the solution transferred to an appropriate volumetric flask (see table 7), a solution of 2 mol/DM
of hydrochloric acid and add water to the mark.
Measure the atomic absorption of lead in the flame of acetylene-air at a wavelength is 283.3 nm parallel to the calibration solutions.
7.3.2. For bronzes with a mass fraction of tin in excess of 0.05%
A portion of the bronze mass, given in table.7, is placed in a beaker with a capacity of 250 cmand dissolved by heating in 10 cm
of a mixture of acids. The solution was cooled, transferred to a volumetric flask with a capacity of 100 cm
, rinse walls of beaker 1 mol/DM
solution of hydrochloric acid and topped up to the mark with the same acid. When the mass fraction of lead more than 1% 10 cm
of the solution transferred to an appropriate volumetric flask (see table 7) and then filled to the mark with a solution of 1 mol/DM
of hydrochloric acid.
Measure the atomic absorption of lead as specified in claim
7.3.3. For bronzes with a mass fraction of silicon in excess of 0.05%
A portion of the bronze mass, given in table.7, is placed in a platinum Cup and dissolved by heating in 10 cmof nitric acid, diluted 1:1, and 2 cm
hydrofluoric acid. Then add 10 cm
of perchloric acid and heated until the appearance of dense white fumes. The residue is dissolved under heating in water.
The solution was cooled, transferred to a volumetric flask with a capacity of 100 cmand top up with water to the mark. When the mass fraction of lead more than 1% 10 cm
of the solution transferred to an appropriate volumetric flask (see table 7), a solution of 2 mol/DM
of hydrochloric acid and add water to the mark.
Measure the atomic absorption of lead as specified in claim
7.3.4. Construction of calibration curve
In eleven of the twelve volumetric flasks with a capacity of 100 cmis placed 1,0; 2,5; 5,0 and 10,0 cm
standard solution B, and 2,0; 3,0; 4,0; 6,0; 8,0; 10,0 and 12.0 cm
standard solution And lead. To all flasks add 10 cm
solution of 2 mol/DM
of hydrochloric acid and add water to the mark.
Measure the atomic absorption of lead as specified in claim
7.4. Processing of the results
7.4.1. Mass fraction of lead (a) percentage calculated by the formula
where is the concentration of lead was found in the calibration schedule, g/cm
;
— the volume of the final sample solution, cm
;
— the weight of the portion contained in the final volume of the sample solution,
7.4.2. The absolute discrepancies in the results of parallel measurements (the rate of convergence) must not exceed the permissible values given in table.2.
(Changed edition, Rev. N 2).
7.4.3. The absolute discrepancies of the analysis results obtained in two different laboratories or two of the results of analysis obtained in the same laboratory but under different conditions (a measure of reproducibility) shall not exceed the values given in table.2.
7.4.4. Control of accuracy of analysis results
Control of accuracy of analysis results is carried out according to State standard samples without tin bronzes, certified in the prescribed manner, a comparison of the results obtained by atomic absorption and photometric, polarographic, gravimetric or titrimetric methods or by a method of additives in accordance with GOST 25086.
7.4.3,
