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Author: Subject: Simple math computation check
JustMe
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[*] posted on 7-5-2008 at 18:38
Simple math computation check


Okay guys, let's not make fun of the geezer. Back in the 1970's when I was a chem major I breezed through molar calculations, dimensional analysis, etc. But when you don't do algebra or every day math you get waaaay out of practice, and I'm not employed in the sciences. Actually, as a typographer/production artist I'm more familiar with base 12 arithmetic (!) which throws off the newbies to this field (I work in Picas and Points, everyone else in - gasp - inches).

Anyway, for personal reasons I want to work out the dose of something I'm going to be taking... my physician is alternative oriented and so I'm going to be trying Lugol's solution. What I want to know is exactly (well, approximately) how much Iodine (and Potassium Iodide) I will be INGESTING. I know that the point HERE is for us to show that we've made the effort, so here is what I hope won't be embarrasing calculations.

The solution is 5% Lugols which means 85% water, 10% Potassium Iodide and 5% Iodine (as listed on the bottle). The oral dose is 1 drop (twice a week).

I remember from my basic chemistry that 1 drop is approximately 1/20 of a mL. So here goes... (approximately)

1 mL has 0.85 gm water (at 1 gm/mL), 0.10 gm KI (at 10%) and 0.05 gm I2 (at 5%)

1/20 mL = 0.05 mL, therefore 0.05 (1 drop) x 0.05 gm (Iodine) = .0025 gm or 2.5 mg of Iodine.

Similarly 0.05 (1 drop) x 0.1 gm (KI) = 0.005 gm or 5 mg of KI.

So one dose of Lugols contains 2.5 mg of Iodine and 5 mg of Potassium Iodide... and given that some cultures consume up to 14 mg of Iodine daily (Japanese) and that the RDA for Potassium is 2,000 mg, I can rest assured to be taking a safe dose.

Did I remember how to do this correctly? Sheesh, don't let your brain rot through lack of usage, guys, LOL.
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pantone159
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[*] posted on 7-5-2008 at 19:48


Those calculations seem right to me.

BTW - I wouldn't be concerned about the toxicity of such small doses. On backpacking trips, I have many times treated water with I2 to disinfect it before drinking. A rough calculation shows that about 16 mg of I2 per liter is used, and you drink more than 1 liter per day. This is more than you are considering.

Now, some people may be allergic to I2, which changes things, but otherwise such small doses are not dangerous.
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woelen
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[*] posted on 7-5-2008 at 22:37


Yes, also to me the calculations seem OK. The only thing is that the density of the solution most likely is somewhat higher than 1 g/ml, I think a better approximation will be somewhere around 1.1 g/ml, so add 10% to your results.



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JustMe
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[*] posted on 8-5-2008 at 05:55


Thanks! Hooray, my brain still works (LOL).
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bio2
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[*] posted on 8-5-2008 at 13:41


Perform a density test or guess as woelen suggested.

1.05 to1.1 seems about right.

Oral solutions are usually expressed as grams per 100ml.
Are you sure this is not on the label?
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JustMe
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[*] posted on 8-5-2008 at 16:38


Quote:

85% water, 10% Potassium Iodide and 5% Iodine (as listed on the bottle)


But hey, all I wanted was an approximation (an order of magnitude kind of thing)... a 10% error isn't much of a concern. I'm aware that this is a chemistry board and all, I just wanted to see if I was in the ballpark with my calculations, and who better to ask?

But since I don't know the actual density, I only have the label to go by. On the other hand, this doesn't mean I don't appreciate the refinements that are being suggested, it shows you guys are on the ball! So thanks again.

Oh, things like a density test and all are out of the question. This is purely for medicinal purposes and crazy expensive for the ingredients - thanks to meth cooks - one can only buy 1 fluid ounce, none to waste.

[Edited on by JustMe]
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