how do I dilute a 0.75% iodine product to get a 12.5ppm no-rinse sanitizer?

[Elysium]

After reading some about no-rinse iodine sanitizer I have decided to try it. On Saturday I'll make a 12.5 ppm,no rinse iodine sanitizier from a surgical scrub iodine base liquid (data sheet) that contains 0.75% iodine.
How shall I dilute it to get a more or less 12.5ppm sanitizer?
By the way....the contact time is 10 minutes in case of this kinda of dilution, isnt it?
And since it is no rinse......do I just put things in the liquid and get them out when I need them, shaking the excess sanitizer off....and that's all? I was told that the surface is sanitized as long as it is wet from the solution.

 

[Astralus]

so PPM is a measure of diluted parts per million, assuming pure iodine is 1 million ppm, .75% iodine would be about 7,500 parts per million.

7500/1000000 = 0.0075 (or 0.75%)

to get down to 12.5ppm you would calculate 7,500 / 12.5 and it will give you the ratio of water to dilute the solution with.

7,500 /12.5 = 600

so for every ML of solution, use 600ml water. I recommend checking to make sure this solution does evaporate like idophor, as it has a sublimating agent that helps the iodine evaporate and become free iodine. The other solution is to rinse in a sterilized bucket of bottled or RO water.

to be safe, use a larger 1:600 ratio like 5ml (1 teaspoon) in 3 litres of water. It will give you a little overhead for making mistakes with minute measurements.

This will also dye any plastic a brownish orange colour, so be careful when using it as well.

hope that helps!

 

[Astralus]

so PPM is a measure of diluted parts per million, assuming pure iodine is 1 million ppm, .75% iodine would be about 7,500 parts per million.

7500/1000000 = 0.0075 (or 0.75%)

to get down to 12.5ppm you would calculate 7,500 / 12.5 and it will give you the ratio of water to dilute the solution with.

7,500 /12.5 = 600

so for every ML of solution, use 600ml water. I recommend checking to make sure this solution does evaporate like idophor, as it has a sublimating agent that helps the iodine evaporate and become free iodine. The other solution is to rinse in a sterilized bucket of bottled or RO water.

to be safe, use a larger 1:600 ratio like 5ml (1 teaspoon) in 3 litres of water. It will give you a little overhead for making mistakes with minute measurements.

This will also dye any plastic a brownish orange colour, so be careful when using it as well.

hope that helps!

I forgot to mention, 5ppm-10ppm is the concentration of iodine in table salt. so a tiny bit probably won't hurt you (take this with a grain of salt; pun intended, I am not a doctor or scientist, just did some research online for you) . shaking off the excess should help as well, let it air out for a min or two before adding your materials, and 10 minutes is the recommended contact time.

 

[Hexadecimus]

Actually no, you can't calculate PPM using mL volume or mass (weight). You need to:
1. Find out what specific iodine compound you're using
2. Calculate the moles present in your iodine solution or powder based its molecular weight
3. Based on that %, calculate how much solution to add to reach your intended ppm

Why? Water is about 18 grams per mole (number of molecules). Pure iodine I2 is 253.8 grams for the same given # of molecules.

If you go by weight, you're off by a factor of 14 right off the bat. If your solution isn't .75% pure elemental I2 and contains other compounds that dissociate to give free iodine (say potassium iodide) then you're off the mark even more.

If you just Google for calculating ppm or moles based on molecular weight, you'll find some good stuff on basic chemistry that will tell you what you need to know. Just don't proceed based on volume or weight.

 

[Elysium]

Actually no, you can't calculate PPM using mL volume or mass (weight). You need to:
1. Find out what specific iodine compound you're using
2. Calculate the moles present in your iodine solution or powder based its molecular weight
3. Based on that %, calculate how much solution to add to reach your intended ppm

Why? Water is about 18 grams per mole (number of molecules). Pure iodine I2 is 253.8 grams for the same given # of molecules.

If you go by weight, you're off by a factor of 14 right off the bat. If your solution isn't .75% pure elemental I2 and contains other compounds that dissociate to give free iodine (say potassium iodide) then you're off the mark even more.

If you just Google for calculating ppm or moles based on molecular weight, you'll find some good stuff on basic chemistry that will tell you what you need to know. Just don't proceed based on volume or weight.

Thanks a lot for the info....but I am either a bit thick for this, or it is just too late and I am tired. I give this a go tomorrow and try to understand it.

I ended up using a 10% Povidone-iodine product, using 1.25 ml/liter. Meaning I put 20 ml in 16 liter of water.