Chemical Forums
Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: Dolphinsiu on October 19, 2007, 09:24:42 AM
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We use flameless atomic absorption to trace the aluminium content in this drink.
I get stuck when I meet the following questions:
1.Which is the more accurate method of obtaining a calibration curve, using peak height or peak area? Explain
My attempted answers:
Peak area due to self absorption at high concentration detemines the constant peak height.
2. Find out what kind of chemical interaction would occur inside an aluminium soft-drink can, and the method used to prevent chemical interaction between beverages and aluminium.
My attempted answers:
2Al + 6H+ --> 2Al3+ + 3H2
To pump more hydrogen gas inside the can.
3. Why nitric acid has to be added to the soft-drink samples?
My attempted answer:
2H+ + CO32- --> CO2 + H2O
To shift the above eqm to the right and increase CO2 evolution.
4. Why should we de-gas or remove the carbon dioxide before measuring the content of trace aluminium in beverages?
My attempted answer:
To prevent gas bubbles that cause error in abosrbance.
5. Why was a flow of argon gas maintained around the atomizer in the analysis?
I cannot the answer this question!
I hope you can help me answer a few questions in above! Thank you!