ICP Solution to Facilitate Rapid Analysis of Impurities in Solid Metallic Samples
Thermo Fisher Scientific Inc. has developed a unique solution to provide fast and efficient impurity analysis of solid metals, including steels, platinum group metals, gold and other conductive materials.
Combining the Thermo Scientific iCAP 6500 Duo ICP emission spectrometer with a Separate Sampling and Excitation Accessory (SSEA), the solution enables close monitoring of all stages of the silver refinery process. The iCAP 6000 Series enables the sensitive, multi-element determination of impurities at ppb and sub-ppb levels in liquid phase matrices and by adding the SSEA accessory, solid phase metallic matrices can also be analyzed with only minimal sample preparation.
The analysis of silver for purity and characterization of impurities is an important example of the application of the combined power offered by the iCAP 6000 Series and SSEA accessory. The capabilities of this unique system are detailed in an application note entitled “Rapid Analysis of Impurities in Silver using a Separate Sampling and Excitation Accessory (SSEA) and Thermo Scientific iCAP 6500 Duo” which is available to download free-of-charge via www.thermo.com/icap
Silver refinery plants receive low assay silver from suppliers and have to analyze the silver, gold and platinum group metals (PGM) content as well as toxic and harmful elements which may interfere with the refinery process. Impurities present in silver require the reprocessing of contaminated products resulting in metal and cost losses. As a consequence, the maximum total concentration of impurities allowed in saleable silver bullion is less than 100ppm with the required detection limits for each impurity less than 1ppm in solid. Extensive purification and sensitive analyses are required in order to ensure optimum product quality. ICP emission spectrometry has been traditionally used for the analysis of silver but this method is associated with extensive sample preparation. By utilizing an SSEA, sample preparation is greatly reduced, allowing for rapid silver analysis in minutes compared with traditional ICP spectrometry which takes hours with sample digestion.
The Kolyma State Refinery, based in the Magadan region of Russia, uses the iCAP 6500 Duo with SSEA for routine analysis of an extended range of silver products, including low assay silver and high purity silver. Using the iCAP 6500 Duo SSEA system, silver values are determined by concentration ratios to give a final silver concentration. Following 10 replicate analyses of a high-purity silver sample, the standard deviation of the impurity results is multiplied by three to produce 3σ detection limits. The results further support the capabilities of the method for high sensitivity, multi-element determination of impurities at ppm and sub-ppm levels in solid silver matrices as well as the ability to determine the silver content itself. Excellent repeatability is also demonstrated.
The iCAP 6500 Duo features superior sensitivity in axial view as well as unique electronic control and triggering capabilities, thus being the only available ICP able to couple with and fully support an SSEA. Using a bloom-resistant CID camera, the iCAP 6500 can analyze for trace elements in the presence of high intensity emissions whilst allowing for full wavelength coverage and maximum resolution, thereby reducing interferences.