ISO 15096-2020 pdf download.Jewellery and precious metals一 Determination of high purity silver一 Difference method using ICP-OES.
8 Procedure
8.1 General
WARNING — Suitable health and safety procedures ihould be followed.
All vecris and reagent bottles shall be teflon (e.g. PFA. FEP) or plastic.
82 Sample solution
For e.ih sample to be .inalysrd. two sample solutions shall be prepared as follows and analysed.
The sample should be etched, washed and dried before use to remove any surface contamination.
Weigh (500 * 10) mg of the sample portion to Ihe nearest 0.1 mg. transfer into a SO ml beaker, and add 7.5 ml of Il and 7.S ml of llNO, (.Z). Heat gendy umil complete disaoluslon olihe sample and continue to heal to expel the nitrogen oxides. Add ID ml of water. Alter cooling to room temperature, transfer the solution from the SO ml beaker to the centrifuge tube, Centrifuge the mixture at 3000 nOun for S mm and transfer the liquid phase into a 50 ml volumetric 1l.isk. AddS ml of water to the residue, centrifuge the mixture again a 3000 r/mnin br 5 main more, and add the newly formed liquid phase to the 50 ml volumetric flask. This operation is repeated two extra time’s. Make up the volume of the volumetric flask water to 50 ml. and mix thoroughly.
Alternatively, after coding to room temperature. filter the solution through a microfiltration system (6.5). add the filtrate to a SO ml volumetric’ flask and make up the volume of the 50101km with wtr to SO ml. and mix thom-oughly. Analyse this solution without delay using the cald,ratlon solutions specified in 11.3.
Add 2 ml of freshly prepared aqua regia (5.3) to the residue alter centritLlgation or mkrofiltratlon (if mlcrohltratlon Is used, the filter shall be dissolved, too). Heat until complete dissolution and continue to heat to expel the nitrogen oxIes, Cool to room temperature, transfer to a 5 ml volumetric flask, rinse with walet and make up with water to 5 ml. Analyse this solution using the aqua regia calIbration solut ions specified in L4.
8.3 Silver matrix calibration solutions (10 g/l)
Weigh three portions of (500 ± 10) mug of the salver (5,9). and dissolve, cool and transfer into 50 ml volumetric flasks each tine as specified in 112
8.3.1 Bbnk solution I
Mike up with water to SO ml. and mix thoroughly.
8.32 Calibration solution 1.
Add 5 ml of stock solution A (5.4) and 5 ml of stock solution B (5.5), make up with water to SO ml. and mix thornughly This solution is unstable over time and should be prepared just before use, or its stability val iclated.
8.3,3 CalIbration solution 2.
Add S ml of stock solution C (5.6) and S ml of stock solution I) (5.7), make up with water to 50 ml. and mix thoroughly. This solution is unstable over time and should be’ prepared just before use, or its stability validated.
The volumes of stock solutions shall be lowered to match the concentration of impurlws In the sample. It is possible to use a multIple.point caNration by adding calibration solutions with other concentrations.ISO 15096 pdf download.