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Measurement and Results - Trace HF and Si analyses by ICP-OES

 
I am currently running a method that tests for silicon and use an Inorganic Ventures multi-element standard to produce a calibration curve on an ICP-OES instrument. My problem is that I cannot produce a calibration curve for silicon. With each replicate, the silicon intensities gradually increase. My question is regarding the HF that is in the standard. On the bottle, it says there is a trace amount of HF in the standard. We use a standard spray chamber that is not resistant to HF. I am wondering if that would be enough HF to eat away at the glass spray chamber, resulting in the gradual increase in intensity.
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admin Total posts: 529

Even trace amounts of HF (~0.1% HF v/v) are enough to generate the results you are observing. We would recommend adding triethanolamine (TEA) to your Si calibration solutions to raise the pH to 5 or higher. At those pH values, HF will not be present, and you should not observe Si leaching from your glass sample introduction system. Below concentrations of ~10 ppm Si is soluble and stable in water, so the increase in pH should not affect the stability of your Si calibration solutions if they are prepared at approximately that concentration or lower.

Posted: 09/05/18 20:10:58

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