More specifically, I would like to know if Si ICP standard solution can be mixed with other ICP standard solutions of different elements (Na, K, ...) to prepare multi-element standard solution for ICP test.
Dear Sir. Concerning your issue about the standard procedure to prepare multi-element standard solution containing Si for ICP-OES test. There are several potential ways in making multi-element working standard solutions by using standards from single-element primary standards, multi-element primary standards, custom-style primary standards, and/or a combination of single-element and multielement primary standards. The criteria are easy, error-proof and economic. In making 32-element working standards from single-element primary standards, an analyst needs to transfer different amounts of standards from approximately 40 bottles of standard solutions (some primary standards at 1,000 ppm and some at 10,000 ppm) to 4–6 volumetric flasks. This process is very time consuming and is prone to mistakes. In addition, it is difficult to control and/or trace the quality of 40 bottles of primary standards. The primary standards are expensive and yet only a tiny portion of these standards may be used. Often, a good portion of the standards still remains long after their expiration dates. Multi-element primary standards are available commercially. However, these solutions usually do not have the desired element combinations and/or the desired concentration ranges for a specific analysis. For example, digested plant solutions contain high concentrations of P, K, Ca, Mg and S (> 100 ppm), but low concentrations of B, Cu and Zn (< 1 ppm). The influence of Ca, K, Mg, and Na as concomitants on silicon analytical signals was evaluated. These elements were chosen based on their potential high concentrations in the samples analyzed. The interference experiments were carried out by monitoring Si signal intensity in a binary solution containing the analyte at 0.5 mg L−1 and the concomitant at 1, 10 or 50 mg L−1 in 1% HNO3 v v−1 . A multi-element solution containing all concomitants at 10 mg L−1 was also analyzed. Interferences were considered significant for signal enhancements or suppressions equal or larger than 10% I think the following below links may help you in your analysis:
https://uwlab.soils.wisc.edu/wp-content/uploads/sites/17/2015/08/ICPOES.pdf
https://geoinfo.nmt.edu/staff/mclemore/projects/environment/documents/SOP_30v8_ICP_OES_final.pdf
https://ac.els-cdn.com/S0026265X1200207X/1-s2.0-S0026265X1200207X-main.pdf?_tid=2bfbc0ea-e680-11e7-8af7-00000aab0f6b&acdnat=1513882563_a1bd2e5c747b912ab0fef4aa762fd7d2
Thanks
At a more basic level, let's consider why Si is so difficult.
1. Si needs fluoride as a complexing agent to remain in solution. BUT for some elements, eg, Ca and Mg, fluorides are insoluble.
2. Si leaches from borosilicate glassware. Standards must be prepared in plastic, not glass.
3. Si is a common contaminant. Purified water may still have Si at 100ppb or more. Airborne dust particles are largely SiO2. Anything stored in glass will have Si, including mineral acids.
Best to keep silicon separate, or combined only with elements of similar solubility such as Zr.
Thank you Professor Isam Eldin Hussein Elgailani for your perfect answer.
I have learnt a lot.
All the best,
In your situation you need to dissolve SiO2 in HF to prepare single element solution. The temperature should be less 70 C to avoid SiF4 loss - or you need a sealed digestion system.
After that you can mix it with other elements. Only plastic glassware should be used all the time because of HF traces.
If Si content is low then you will not care about Ca, Al&K - in other way you should think about insoluble CaF2 and KAlF6 (in this case you can use H3BO3 to mask fluoride ions).
You shouldn't add any additional fluorides to complex Si during diluting - SiF6 ions are stable enough and will not hydrolize.
Dear colleague,
I agree with Professor Isam Eldin Hussein Elgailani and stephen chace.
solutions of silicon should not be contained some of elements because the presence of fluoride ion.
The Best,
- Badges
- Science topic
- Similar topics
- Phytochemistry
- Extracts