BS EN 14538-2006 pdf download.Energy Institute – Library and Information Service.
NOTE In order to minimize pollution of the solutions, it is recommended to prepare all the determination solutions in polyethylene bottles. Do not touch surfaces that could come in contact with working solutions New glassware should be filled with sodium-free water and to be left for two days before use to remove soluble sodium. This is especially important when this procedure is used for the determination of sodium and/or potassium.
5.3 ICP OES spectrometer
5.3.1 General
ICP OES spectrometers (simultaneous or sequence devices) equipped for the analysis of organic liquids are suitable. Both setup and operation of the ICP OES spectrometer shall be done in accordance with operating instructions of the manufacturer.
NOTE I Depending on the type and construction of the ICP OES spectrometer (radial, axial, detectors sensitivity, etc.) it may sometimes be necessary to select wavelengths different from those listed here. In such cases, a separate optimization of the instrument parameters and possibly also of the optimal dilution (see 9.1) is strongly recommended.
NOTE 2 The calibration solution with an element content of 1 mg/kg (7.4) can be used to check the correct instrument performance.
5.3.2 Recommended wavelengths for Calcium and Magnesium
The following wavelengths are recommended for the analysis, because they have been found to exhibit minimal interference in daily practice:
Calcium 422,673 nm;
Magnesium 279,553 nm.
Depending on the ICP OES spectrometers optical configuration also other specific wavelengths can be selected, like 317,933 nm, 393.366 nm or 396,847 nm for Calcium and 285,213 nm for Magnesium, if these lines are free from interferences (see also Note 1 under 5.3.1).
5.3.3 Recommended wavelengths for Sodium and Potassium
The following wavelengths are recommended for the analysis, because they have been found to exhibit minimal interference in daily practice (see also Note I under 5.3.1).
Sodium 588,995 nm or 589,592 nm;
Potassium 769.897 nm or 766,490 nm.
6 Sampling
The masses given in 7.3, 7.4, 7.5 and 7.6 correspond to a nominal element content of 500 mg/kg per element in the standard solutions (4.3) and (4.4). Calculate the exact concentrations for the calibration solutions, taking into account the exact weights, All prepared solutions shall be homogenized by vigorous shaking.
NOTE 1 As a strong general recommendation, the solutions used for calibration should be freshly prepared. If that Is not possible, the samples should be stabilized using a suitably small amount of a stabilizing agent like 2-Ethyihexanoic acid, which has been shown to be free of the elements under investigation. Expenence from daily practice has shown that such stabilized samples can be used for about 14 days. However, there is also sufficient evidence that calibration standard (7.3) In particular Is not sufficiently stable, so that It Is strongly recommended to prepare fresh solutions for each new calibration,
NOTE 2 The dilution factors for the blank solution, the calibration solutions and sample solution should be selected such that the viscosities are as close to one another as possible. This can often be achieved by using a somewhat higher dilution factor.
7.2 Blank solution
Approximately 30 g paraffin oil (4.1) is weighed, with a precision of 001 g, into a 250 ml PE bottle (5.2), filled
up with kerosene (4.2) to a total sample mass of approximately 100 g, with a precision of 0,01 g.
7.3 Calibration solution with a nominal element content of 0,5 mglkg
For each element, approximately 0,1 g standard solution (4.3) is weighed, with a precision of 0,000 1 g, into a
250 ml PE bottle (5.2). Then approximately 30 g paraffin oil is added, with a precision of 0,01 g. Subsequently,
kerosene (4.2) is added to make up to a total sample weight of approximately 100 g. with a precision of 0,01 9.
Special attention shall be executed in using this calibration solution, as it is not as stable as the other ones.
7.4 Calibration solution with a nominal element content of I mg/kg
For each element, approximately 0,2 g standard solution (4.3) is weighed, with a precision of 0,000 1 g, into a
250 ml PE bottle (5.2). Then approximately 30 g paraffin oil is added, with a precision of 0,01 g. Subsequently,
kerosene (4.2) is added to make up to a total sample weight of approximately 100 9, with a precision of 0,01 9.
7.5 CalIbration solution with a nominal element content of 5 mg/kg
For each element, approximately 1 g standard solution (4.3)is weighed, with a precision of 0,000 1 g, into a 250 ml PE bottle (5.2). Then approximately 30 g paraffin oil is added, with a precision of 0,01 g. Subsequently, kerosene (4.2) is added to make up to a total sample weight of approximately 100 g. with a precision of 0,01 g.
7.6 Calibration solution with a nominal element content of 10 mg/kg
For each element, approximately 2 g standard solution (4.3) is weighed, with a precision of 0,000 1 g into a 250 ml PE bottle (5.2).BS EN 14538-2006 pdf download.