BS EN ISO 4946:2016 pdf download
BS EN ISO 4946:2016 pdf download.Steel and cast iron ——Determination of copper—2,2″-Biquinoline spectrophotometric method.
7.3.3 Preparation of the compensating solution
Transfer an aliquot portion of the test solution (LII) similar to the aliquot portion for the development of the colour (7.32) to a 50 ml one-mark volumetric flask. lithe aliquot portion is 5 ml, add 5 ml of perchloric acid (4.5)
Add, in the following order, shaking after each addition:
— 5 ml of ascorbic acid solution (41);
— 25 ml ofdimethyliormamlde solution (4.6).
Dilute to the mark with water and mix. Cool for 5 mm in a water-bath at about 20°C.
Finally, readjust the volume and mix again.
7.3.4 Spectrophotometric measurement
Carry out the spectrophotometric measurement of the test solution (7.11) at a wavelength of about 545 nm, in a cell of 2 cm optical path length, after adjusting the spectrophotometer (cJause5) to zero absorbance in relation to the compensating solution (7.13).
For copper contents below 0,06 % (mass traction), 4 cm cells may be used if the sensitivity of the spectrophotometer Is not sufficient with 2 cm cells.
7.4 Establishment of the calibration graph
7.4.1 Preparation of the calibration solutions
Into each of a series of 100 ml beakers, add 0,5 g i 0.01 g of high purity iron (Li) and 10 ml of hydrochloric acid (42). Cover with a watch.glass and heat gently until dissolved, then oxidize by adding nitrIc acid (4.3) drop by drop. Add the following volumes of the standard copper solution (ill) to the beakers, respectively: 0 ml, 2 ml, S ml. 10 ml, 20 ml, 30 ml, 40 ml and 50 ml.
Add 10 ml olperchloric acid (4.4) and evaporate to fumes. Continue fuming for 3 mm.
Cool, dissolve the salts with 20 ml of water transfer the solutions quantitatively to 100 ml one•mark volumetric flasks, dilute to the mark with water and mix.
From each volumetric flask, take 10.0 ml of the solution and transfer respectively into a series of 50 nil one-mark volumetric flasks. The zero term represents the compensating solution.
For the colour development. proceed as dIrected in 7.12. beginning at Add, in the following ordcr….
The copper concentrations in the 50 ml calibration solutions are respectively 0 pg. 0,2 pg. 0,5 pg. 1 pg. 2 pg, 3 pg. 4 pg and 5 pg of copper per millilitre.
7.4.2 Spectrophotometrlc measurement
Carry out the spectrophotometric measurement of absorbance of each calibration solution (7.4.1) at a wavelength of about 545 nm, in a cell of 2 cm optical path length, using the zero term calibration solution as the compensating solution as described in 73.4.
7.4.3 Calibration graph
Establish the calibration graph by plotting the net absorbance values against the copper concentrations, expressed in micrograms per millilitre, in the calibration solutions.
9.2 Repeatability
The difference between two single and independent results found on identical test material by one analyst using the same apparatus within a short time interval in the normal and correct operation of the test method will exceed the repeatability, r, only in one case in 20 cases.
9.3 Reproducibility
The difference between two single and Independent results found by two operators working in different laboratories on identical test material in the normal and correct operation of the test method will exceed the reproducibility, R. only in one case In 20 cases.
10 Test report
The test report shall include the following information:
a) all information necessary for the identification of the sample, the laboratoryand the date of analysis or of the test report;
b) method used with reference to this International Standard, i.e. ISO 4’J46;
c) results and unit in which they are expressed;
d) any unusual features notcil during the determination;
e) any operation not specified in this International Standard or any optional operation which might have Influenced the results.
