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/sci/ - Science & Math

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2262741 No.2262741 [Reply] [Original]

Urgent help would be appreciated

I want to test how much of a metal has been absorbed into a food. I would use a sample of food for control and a sample exposed to a metal.
Would a spectrophotometer be the correct machine to test this?

>> No.2262761

works if the metal absorbs in the spectrophotometer's range.

>> No.2262766

If it's a ferrous metal and a dry food, you can just crush it up and use a rare earth magnet.
Also, you could just weigh it or check the density. No need to get all fancy.

>> No.2262776

>>2262761
Is there a simple way to determine that? I just did a quick google search, found a $700 dollar book explaining it...

>> No.2262788

>>2262766
Maybe I'm overthinking.
But I'd still like to have the option of using it. I think with the other options, it wouldn't be as precise.

>> No.2262808

ICP-AE (inductively coupled plasma atomic emission spectrometry) testing will do the trick easily and can detect parts per trillion. what metals you looking to test op?

>> No.2262822

>>2262788
I tend towards keeping things simple. If you let the metal absorb and then separate it from the food (such as soaking the food in something that would basically eat it and not the metal) you'd be left with all the metal absorbed. I guess it just depends on how accurate you want your measurement to be.

>> No.2262869

>>2262808
That's interesting, but I only have access to a basic spectrophotometer.

Metals used in commercial canning would be tested. Tin, etc.

>>2262822
That's also a pretty good idea, I'll definitely keep that in mind. Thanks!

>> No.2262871

I think a chemical test would be better personally.
Mush the food up in a suitable solvent (probably water or something that will disolve fat), if the metal absorbed is iron, add a source of hydroxide ions to excess then do an acid-base titration to work out the amount of Iron hydroxide present.

>> No.2262899

>>2262869
this is the icp poster...

u mean u only have IR and UV at ur disposal to investigate this?

>> No.2262933
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2262933

>>2262899
This thing.

>>2262871
That's definitely an option. Bot to throw a wrench in this but: What if I want to test if the pH of the food will affect the absorption at all? Then it won't work out will it?

>> No.2262944

>>2262933
op i have just completed a phd in chemistry regarding heavy metal adsorption by insoluble hydrous oxides so i am pretty clued up and thats why i mentioned the icp machine, do u have a yahoo account or email? i will try help u as much as possible if u like

>> No.2262953

>>2262933
oh and by the way using a IR/UV will only tell if certain functional groups are present and not concentrations or metals really

>> No.2262981

>>2262953
Thanks for your offer, but I'm not sure if I really need to waste your time.
I'd measure out a control first, then I'd measure out the food absorbed by metal.

I'm starting to think that it won't work like a mass spectrometer would.

>> No.2263003

>>2262981
it is no problem, your decision. But no IR/UV will not detect metals. Secondly these tests only allow u to see if something is there ie could tell u if a carboxylic group was present due to its resonance, however you could not work out the concentration of the sample. hope it helps

>> No.2263019

>>2263003
Damn! I think I'll go the simpler route and work with chemicals. Thanks for your help.

>> No.2263024

>>2263019
Good Luck!

>> No.2263032

Going to expensive instrumentation when a simple solution is staring you in the face.

Titrate samples from before and after treatment with metal with EDTA. Assumes solubility in water which isn't a bad assumption for foodstuffs.

>> No.2263066

>>2263032
Yeah. I realize that. Wasted my time.
Alright, I'm going for a titration.

>> No.2263139

>>2263032
but depending on the lewis acidity of the metal i.e cd wont adsorb to edta as well as something like cr III, on top of that edta is not very soluble in water no?