1、s 1 EUROPEAN STANDARD EN 10 181 the Secretariat of which is allocated to the Dansk Standardiseringsrad (DS). It has been submitted to the CEN Formal Vote following the decision of the Coordinating Commission (COCOR) of the European Committee for Iron and Steel Standardization on 1987-11-24/25. It ha
2、s been adopted and ratified by CEN BT on 1988-11-05. According to the Common CEN/CENELEC Rules, following countries are bound to implement this European Standard : Austria, Belgium, Denmark, Finland, France, Germany, Greece, Ictlind, Ireland, Italy, Luxemburg, Netherlands, .Norway, Portugal, Spa:n,
3、Sweden, Switzerland and United Kingdom. Note in clauses 1 and 9 EURONORM shall read EUROPEAN STANDARD. C *.EN 10 181 Page 3 Chemical analysis of ferrous materials Determination of lead in steels Flame atomic absorption spectrometric method CONTENTS 1. SCOPE AND FIELD OF APPLICATION 7. PROCEDURE 2. R
4、EFERENCE 7.2 Bhk test 3. PRINCIPLE 7.4 Eaabtishment of ihc cllibration graph 4, REAGENTS 8. EXPRESSION OF RESULTS 7.1 Tesi portion 7.3 Detamilution 5. APPARATUS 9. TEST REPORT 6. SAMPLING ANNEX: Sunpkc terted 1. SCOPE AND FIELD OF APPLICATION This EURONORM specifies a method for the determination of
5、 lead in steels by means of flame atomic absorption spectro- metry. The method U appiicable to non-alloy and low-alloy steels with led contenu of 0.003 to 0.5% (dm) (see Annex). 2. REFERENCE EURONORM 18 - Selection and prepuation of sampla and test peces for steel and iron and stcd products General
6、guidciines for the application offlame atomic absorp- tion spccuomeuic methods ue in course of preparation. 3. PRWCIPLE Dissolution of a test ponion with hydrochloric rcid followed by oxidation with nitric acid. Spraying of the solution into an ur-acetylene flame. Determi- nation of the lead by mean
7、s o the spectromeuic musuranart of the atomic rbsoorption of the 283.3 nm line emitted by a led rdiation murce. Te inrmmcnt ir caiibrued by addition of a lead standard soiution to i similu matrix to that of the test solution. 4, REAGENTS During the analysis use only reapenu of recognized analytical
8、reagent quality and hiving a very low lead conteni, and only distilled water or water of cquivaknt purity. Carefully check the lead content of ail wenu. If possible, ux only freshly prepared distilled OT d9onized water. 4.1 Iron, of high pu*, with I lerd content 99.976 pun) in boiling hydrochloric a
9、cid p 1.19 dmi, diluted I + 7 (V/W and afterwards With watet and acetone. Dry the lead in a vacuum daiccuor. Weigh, to the riurrtt 0.001 g, ipproximately 0.5 g of the purifd Id. Transfer th8 weim mass to a 400 ml beaker and disaoive in 25 ml ni a lead radia- tion source; supplies of au and acetylene
10、 suffi- ciently pure to give a clear fuel-kan flame, free from water and oil, and free from lead For example, if the top and bottom calibration solutions represent 0.506 and 0.0516 lead in the sample. the precision called for (as two standud deviations) would be 0.01516 and 0.005% kad respectively,
11、assuming curve linehty. 5.1.2 Addithal paformuicc rcquimmts The atomic absorption spectrometer used wiU be satisfactory if after optimization according to 7.3.4 the limit of detection and characteristic concentration are in reasonable agreement with the values given by the manufacturer and it mets t
12、he following performance requirements. 5, I. I Minimum precision The standard deviation of IO measurements of the absor- bance of the most concentrated calibration solution shall not exceed 1.5% of the mean absorbance, It is also desirable that the instrument should conform to the following addition
13、ai performance requirements. (a) Characteristic concentration. - The characteristic con- centration for lead in a matrix similu to the finai test solution shall be better than 0.6 pdml. (b) Limit of detection. - The limit of detection of lead in a matrix similar to the final sample test solution sha
14、ll be better than 0.3 pdrnl. S.2 Ancillary equipment The standard deviation of IO measurements of the absorbance of the least concentrated calibration solution (excluding the zero calibration solution) shall not exceed 0.5% of the mern absorbance of the most concentrated calibration solution. A stri
15、p chart recorder andor digital readout device is recom- mended to evaluate the criteria in 5.1 and for all subsequent measurements. 6. SAMPLING Sampling shall be carried out in accordance with EURONORM 18. 7. PROCEDURE 7,1 Test portion Weigh the mass (m) indicated below to the MU 0.001 g: m = 28 i 5
16、%. If a residue hu b#n ktl in the solution, filter off a portion through a dry medium textured filter paper, discarding the fufi mnnings. 7.2 Blanktest 7.3.2 Prepuitkn Octh calibration dudons With each analytical run, carry out an andysi on a ragent blank in parallel with the test portion analysis,
17、using identical reagents, conditions, analytical procedures and dilutions throughout. 7.3 Determination water and mix. 7.3. I Preparationoftheten solution Place the test portion (7.1) in a 250 ml beaker. Add 30 ml of hydrochloric acid (4.2). Heat gently until the reaction ceases. Oxidize with 5 ml n
18、itric acid (4.3). Boil the solution for 5 minutes to remove oxides of nivogen. Cool, transfer the solution to a 100 ml volumetric flask, dilute to the mark with water and mix. Ph IO g of iron (4.1) in an 800 ml beaker and add 100 ml of hY- acid (4.2). Heit (entiy until the reaction ceases. OXidizc W
19、ith 20 ml of nitric rad (4.3). Boil the solution for 5 minuks to remove oxides of nitrogen. TrMder to a 250 ml volumetric flask, dilute to the mark with Transfer L series of 25.0 ml rliquots to 50 ml volumetric fuk8. Add, by means of a burette or pipette, respectively O: 1.0; 2.0; 3.0; 4.0; 5.0; 6,O
20、; 8.0 and 10.0 ml of the lead reference solution (4.4), dilute to the mark with water and mix. NOTE - 1 ml of led reference solution (4.4) is quivalent to approximately 0.0516 (dm) in the sample, 7.3.3 Adjustment of atomic absorption qefomet (5.1) Type of lamp: Wavelength: 283.3 nm. Flame: Air-acety
21、lene clear fuel-lean Lamp current - Slit width: Follow manufacturers NOTE - The manufacturers recommendations should be closely followed and particular attention is drawn to the following safety points: (a) the explosive nature of acetylene, rnd regulations con- cerning its use; (b) the need to shie
22、ld the eyes of the operator from U.V. radiation by means of tinted glass; (c) the need to keep the burner head clear of deposits. A badly clogged burner may cause a flash back. (d) make sure that the liquid trap is filled with water. Lerd radiation source. flame adjusted for maximum lead response. r
23、ecommendations. 7.3.4 Optimkation of the atomic rbsorption spectromrrCr Follow the manufacturers instructions for preparing the in- strument for use. When the current to the lamp, the wavelength and the flow of gas have been adjusted and the burner lit, spray water until the indication has stabilize
24、d. Sa the absorbance vdue to zero. Choose a damping setting or integration time to give a signal steady enough to fulfil the precision requirements (5. I. i), Adjust the flame to be clear fud-lean and the burner height to about I cm below the light path. Spraying. alternately, the high and zero cali
25、bration solutions, adjust the gas flow and burner position (horizontally, vertically and rotationally) until the dilfetence in absorbance between the calibration solutions is at a maximum. Evaluate the criteria of 5. I. I to ensure that the instrument is suitable for the determination. settings 2N 1
26、0 181 Page 5 7.3.5 Atomic absorption meisurmmts Set the scale expansion so that the top calibration solution gives nearly full scale deflection. Aspirate the calibration solutions in ascending order repetitively until each gives the acceptable precision (see 5,1.1), thus showing that the instru- men
27、t has achieved stability. Select two calibration solutions, one having an absorbance just lower than the test solution and one just higher. Aspirate these first in ascending order. then in descending order, with the test solution as the middle solution in each case measuring the absorbance in relati
28、on to water. Aspirate the complete range of calibration solutions again, It is recogmzed that these procedures cannot be followed with automatic instruments which accept two calibration solutions only. In this cue it is suggested that the two sandwiching solutions should not be uscd for the primary
29、calibration but should be 8MiySd dtanitdy Ath the tCSt solution. Obtain the na mern absorbance of each calibration solution by subtracting the mean rbtorbanct of the zero calibration solution. Obtain the mean absorbance of the test solution and the mean absorbance of the ragent blink solution. Conve
30、rt the mean absorbances of the test solution and of the reagent Mink solution to micrograms of lead per millilitre by means of the calibration graph (7.4). 7.4 Establishment of the calibration graph It u necessary to draw up a new calibration graph for each series of detcnninitions, and for the rang
31、e of lead contents Prepare a calibration graph by plotting the net mean absor. bance values of the calibration solutions against micrograms of lead per millilive, calculrted according to 4.4. Refer the net rbmrbuiccs of the two adjacent cdibration solutions to the graph. if these two calibration rea
32、dings do not deviate from the graph by more than the permitted precision criteria then the test solution tudings are acceptable. expected. - 8. EXPRESSION OF RESULTS The percentage by mass of lad (Pb) is given by the expres- 6 is the concentration of lead in the test solution. expressed in sion POlm
33、l. (b-C).100 100 b-c m lm Pb%(m/m)= i ,-=- c is the concentration of Ierd in the reagent blank solution. expressed in pg/ml. Where: m is the mass of the test portion, in g. 9. TEST REPORT The tes1 report shall contain the following particulars: (d) any omrations not specified in this EURONORM or any
34、 -. (a) the method of analysis used by reference to this EURO- NORM: opiional operations which could have had an influence on the result; (b the results obtained. as well as the form in which they are (e) all indications necessary for the identification of the expressed: siunde: (cl any particular d
35、etails which may have been noted during the determinauon; (0 the laboratory and the date of analysis. CEN ENxLO*LBL 89 W 3404589 000021b 5 I CRM EN 10 181 Page 6 Alloy iyp Lead i6 ANNEX BCS 27 I BCS 330 BCS 214 BCS 456 BCS 320 BCS 329 BCS 212/1 NBS 13h EURONORM 039-2 Mild steel Mild steel Mild steel
36、 MM steel MM iteet Mild steel Led4 stl Ledbd rtccl Leaded rtl(i.5% Mn; 0.236 S) 0.0025 0.003 0.008 O.Ol0 0.015 0.050 0.22 0.228 0.308 - The method has also been applied for the uiilysis of the BCS 336: Cr-Ni stainless steel 0.0007% Pb following highly-aUoyed CRMs, with acceptaMe results: NBS Ii: Ci-Ni-Mo suinkss steel 0.001% Pb
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