BS EN 14938-2-2010 pdf download.Copper and copper alloys Determination of bismuth content
Part 2: Flame atomic absorption spectrometric method (FAAS).
4.4 Bismuth stock solution, 1,0 gil Bi
Weigh (0,25 ± 0,001) g of bismuth (Si > 99,999 9 %) and transfer it into a 250 ml beaker. Add 50 ml of nitric acid
(4.2) and cover with a watch glass. Heat gently until the bismuth is dissolved and then bring to the boiling point until
the nitrous fumes have been expelled. Cool to room temperature and transfer the solution quantitatively into a
250 ml one-mark volumetric flask, dilute to the mark with water and mix well.
1 ml of this solution contains 1,0 mg of Bi.
4.5 Bismuth standard solution, 0,1 gIl Bi
Transfer 25,0 ml of the bismuth stock solution (4.4) Into a 250 ml one-mark volumetric flask. Dilute to the mark with water and mix well.
Prepare this solution immediately prior to use.
1 ml of this solution contains 0,1 mg of Si.
BS EN 14938-2:2010
EN 14938-2:2010 (E)
4.6 Copper base solution, 20 gIl Cu
Into a 600 ml tall beaker weigh 10,0 g of bismuth-free copper (Si ≤ 0,005 %). Add 50 ml of distilled water and, in small portions. 50 ml of nitric acid (4.2). Cover and heat gently until the copper is completely dissolved, then continue heating to the boiling point. Cool to room temperature, Wash the beaker cover and the sides of the beaker with water. Transfer the solution quantitatively into a 500 ml one-mark volumetric flask, dilute to the mark with water and mix well.
5 Apparatus
5.1 Atomic absorption spectrometer. fitted with an air/acetylene burner.
5.2 Bismuth hollow-cathode or electrodeless discharge lamp.
6 Sampling
Sampling shall be carried out In accordance with ISO 1811-1 or ISO 1811-2, as appropriate.
Test samples shall be in the form of fine drillings, chips or millings with a maximum thickness of 0,5 mm.
7 Procedure
7.1 Preparation of the test portion solution
7.1.1 Test portion
Weigh (1 ± 0.001) g of the test sample.
7.1.2 Test portion solution
Transfer the test portion (7.1.1) into a 250 ml beaker. Add 10 ml of distilled water, 0.5 ml of nitric acid (4.2). 0,5 ml of hydrogen peroxide (4.3) and 20 ml of hydrochloric acid (4.1). Cover with a watch glass and heat gently until the test portion is completely dissolved, then continue heating to the boiling point. Cool to room temperature. Wash the beaker cover and the sides of the beaker with water.
Transfer the dissolved test portion into a 100 ml one-mark volumetric flask. Dilute to the mark with water and mix well.
7.2 Blank test
Carry Out a blank test simultaneously with the determination, fo’lowing the same procedure and using the same
quantities of all reagents as used for the determination, but omitting the test portion.
7.3 Check test
Make a preliminary check of the apparatus by preparing a solution of a reference material or a synthetic sample containing a known amount of bismuth and of composition similar to the material to be analysed. Carry out the procedure specified in 7.5.
7.4 Establishment of the calibration curve
7.4.1 Preparation of the calibration solutions
7.4.1.1 General
In all cases, copper and chlonde concentrations in the calibration solutions shall be similar to those of the test portion solutions.
The presence of copper in the calibration solutions compensates for chemical interaction effects of copper in the test solution. Normally no similar additions are required to compensate for the effect of alloying elements. If an alloying element is present in the material to be analysed in mass fraction > 10 %, an appropriate mass of this element shall be added to the calibration solutions. The volumes of copper base solution added (4.6) have been calculated to compensate for chemical interaction effects of copper in test solutions of copper or high-copper alloys. Overcompensation may occur if the same volumes are added when the test samples are copper-based alloys where the percentage of copper is lower. In these cases the volumes of copper base solution shall be decreased to match the copper content of the test sample in solution.
The bismuth concentration of the calibration solutions shall be adjusted to suit the sensitivity of the apparatus used, so that the curve of absorbance as a function of concentration Is a straight line.
NOTE The amount of HNO3 in the sample solutions is different from that in the calibration solutions. This does not effect the measurement.
7.4.1.2 Bismuth mass fractions between 0,01 % and 0,05 %
Into each of a series of five 100 ml one-mark volumetric flasks, introduce 20.0 ml of hydrochloric acid (4.1) and the volumes of the bismuth standard solution (4.5) and of the copper base solution (4.6) shown in Table 1. Dilute to the mark with water and mix well.BS EN 14938-2-2010 pdf download.