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Quality Issues
There are several quality issues that are important with respect to multi-element chemical standards:
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Many of the topics above have been discussed in other publications on our site. Please use the links provided throughout this
article to gain a better understanding of the issues discussed below.
Accuracy
The accuracy of a certified reference material (CRM) standard is dependent upon:
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or multi-element blend).
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uncertainty calculations will be discussed in part 3 of this series).
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Elements at ppb Concentration Levels* for detailed information on physical stability.
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in place helps to prevent laboratory blunders. See ISO Guide 34, 17025, and 9001 Explained* to learn more about out
which International Organization of Standardization (ISO) standards are most important for trace analyses.
Purity
Purity becomes an issue when using starting materials of single element blends to prepare multi-element blends. The degree of
importance increases as the relative order of magnitude of the components increases. Known purity and hopefully very clean
materials are critical in the execution of ICP-OES spectral interference studies. These studies typically involve the aspiration of
a 1000 μg/mL solution of a single element while collecting the spectral regions of analytes that may be interfered with.
Inorganic Ventures’ laboratory has purchased many materials claiming a purity of 5 to 6-9’s. However, it’s never a bad idea to
confirm a manufacturer’s claims. For more information regarding purity considerations, please consult the following online
articles:
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Chemical Compatibility
It’s important for the multi-element blends to be compatible with the containers in which they are prepared and stored. It’s
equally important that they are compatible with the introduction system of the instrument(s) used to analyze the blend and
with the other analytes within the blend. Some points to consider:
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or chromate, ppt of the alkaline and rare earths with F- in HF matrices, ppt of fluorinated elements like Sn(F)x-y in the
presence of elements that would complex with the fluoride and therefore ‘pull it away’ from the metal stabilized as the fluoride
complex, etc.
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