Applications for trace elemental analysis are quite common, ranging from toxic metal analysis in water, lead analysis in toys, to trace metals analysis for semiconductor, with detection level requirements ranging from parts per million (ppm) to sub parts per trillion (ppt). The trace contamination of certain elements can lead to severe health problems or cause defect in products.
One of the biggest challenges in trace elemental analysis is overcoming interferences during analysis. Since elemental analysis is often used to determine trace element concentrations, sensitive and precise measurements are critical. To ensure optimum analytical performance, it is necessary to identify and correct any potential interferences.
Experts in our recent webinar, now available on-demand and titled Demystifying Interference Removal, (link to registration page; you will need to fill out a short form to play the webinar), analyze the sources of the interference for ICP-OES, ICP-MS, and high-resolution ICP-MS (HR-ICP-MS) analysis and present solutions on removing interference.
Three types of interferences are often encountered during elemental analysis: physical, chemical and spectral. Physical interferences can often be corrected for with careful instrument optimization, intelligent sample preparation and proper use of internal standards. Chemical interferences such as ionization effects, molecular species formation and plasma loading must be carefully evaluated and removed.
Spectral interferences must also be corrected for; however, these interferences can be more challenging to properly quantify and remove. Different removal mechanisms can are typically employed for different types of instruments. For instance, ICP-OES typically utilizes off-peak background correction and inter-elemental correction methods for spectral interference removal. For ICP-MS, collision cell technology (CCT) can be used to remove polyatomic and precursor interferences. Our ICP-MS instrument (Thermo Scientific iCAP Q ICP-MS) contains an innovative QCell which removes interferences using kinetic energy discrimination (KED) and an automatic low mass cut-off filter.
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By the way, if you are interested in trace elemental analysis for water, especially chromium speciation coupled with ion chromatography technology, do check out our recently launched water analysis community website for applications, technical notes, posters and past elemental analysis webinars as well.
- Do check out more water analysis chromatography applications on this blog.
- Our Chromatography Solution Online Center features many useful and complimentary chromatography tools which can help speed up your analysis. The site is updated on a monthly basis; therefore, do check out the Archives section to see what was previously featured.
If you have questions on the contaminant list or on water analysis, do enter them in the Comments box below; I look forward to hearing from you.
Wei Liu is a senior market development manager with a focus on trace elemental analysis applications in environmental and industrial markets in the Chromatography and Mass Spectrometry Division at Thermo Fisher Scientific Inc. As a former scientist who worked in the field of industrial enzymes and drug discovery, and following his MBA from the Haas School of Business, UC Berkeley, Wei has worked in a wide range of roles including marketing consultant, product manager, and market research manager. Wei completed his Ph.D. in Molecular Microbiology at the University of Illinois at Chicago, and post doctoral training at Stanford University; he has 13 international scientific publications and 4 patents to his credit.