[AcesHigh]

I'm planning a high-school chemistry experiment.

I want to investigate the concentration of iron (III) in common food sources.

The best way to do this is to use spectroscopy I've found, and luckily my school's chemistry lab have one of these machines! (:

<b>I was wondering which types of foods i could investigate by spectroscopy? Is it just liquids like fruit juices or can solid foods like nuts, raisins or meat be investigated to?</b>

Also, does anyone know what wavelenght the iron when reacting to SCN is absorbed at?

I guess the compound i'd be investigating would be Fe(SCN)3, but do this substance occur naturally in foods, or would i have to add SCN- in order to capture the Fe+ in order to count the concentration?

[resc]

Check out http://www.owlnet.rice.edu/~chem384/binstuf/UV_Vis_Iron_2002.pdf and original J chem Ed article.


Also, if you are going to go with your original suggestion, one thing to note with the Fe(SCN)3 complex is that it is in equilibrium with the consituent ions, so you need to work out the equilibrium constant, and then use UV/vis spectroscopy. This is a messy experiment, I have found the complex to photodegrade somewhat.

[AcesHigh]

Thank you so much for the great link and suggestions!

But could you help me by explaining how I can find the equilibria between the iron complex and the consisten ions? And also, how could you tell that the iron complex photodegrades? Is it then necessary to perform the preparations in a environment with low frequency lights to obtain more accurate results?

//Regards

[resc]

Hi

If you follow the work that was in the links, there is no need to worry about the equilibrium, as your calibration curve should implicitly sort that out.

Re photodegradation, I've noticed in working with this compound that the compound is slightly photolabile, but in the context of a 3 - 4 hour experiment (eg in school, college etc) it should be negligible.

Glad you found the links useful

Thank you so much for the great link and suggestions!

But could you help me by explaining how I can find the equilibria between the iron complex and the consisten ions? And also, how could you tell that the iron complex photodegrades? Is it then necessary to perform the preparations in a environment with low frequency lights to obtain more accurate results?

//Regards