Hi, does anyone know the best way to do the determination of iron in cat food, or knows where to find info about it. I'm thinking about turning it to ashes and then form a complex with SCN- and later calculate the concentration with a calibration curve.

Question

mathmate · Answer

What you suggested is one valid way to find the iron content in food. However, if you are concerned with nutrition, it is important to note that iron absorption rate depends on the source (animal 20-35%, & plant 2-20%), plus other conditions to enhance or inhibit absorption. So an overall content may not exactly serve your purpose. See for example: https://www.myfooddiary.com/blog/eating-to-increase-iron-absorption

tatianagomezb · Answer

thanks for answering, my intention is to write an essay easy to replicate, and accurate enough within the lab context.

aaronq · Answer

The best way is to do elemental analysis is to use atomic emission spectroscopy (AES), the common (modern) instrument is ICP-AES and let's you do this easily. But yeah, definitely putting into an oven (to turn to ashes) would be a preparatory step. And, of course, you should always use the standard addition method.

tatianagomezb · Answer

The requirement is to use whatever method we have already studied. I'm afraid we haven't done any aes just yet. We did see Uv vis spectrometry. Could I check the maximum wavelength of absorption of the complex with the standard solution? And then continue with the rest.

aaronq · Answer

Oh okay, then uv-vis spectrophometry would be an acceptable method. Also, unless the Kf is very high for the complex, you'll have to include some stoichiometry to account for the iron that didn't form a complex with the thiocyanate ion but was present in the solution.

tatianagomezb · Answer

And how would I ensure that happens. I mean. I know that the Kf is not to high, it's in the order of two. How would I make sure that I can complex most of the iron iii present with the SCN-

aaronq · Answer

Just take the necessary steps to remove the iron bound to proteins, etc. Charring should be sufficient to do this.

tatianagomezb · Answer

Great. I think we got it. Thanks so much for all your help.