ppm to milligrams of...

Iodine in a kelp powder. Can you guys help me verify I'm doing this correctly?

If the kelp powder analysis says that the iodine content is 4,687 parts per million.

Am I correct in calculating that in 1 gram of this kelp powder that there are 4.687 milligrams of iodine?

Thanks...just need to be sure.

Jeff

[Mrs X]

Originally Posted by jnhermann

Iodine in a kelp powder. Can you guys help me verify I'm doing this correctly?

If the kelp powder analysis says that the iodine content is 4,687 parts per million.

Am I correct in calculating that in 1 gram of this kelp powder that there are 4.687 milligrams of iodine?

Thanks...just need to be sure.

Jeff

"parts per million" means exactly that. 1 gram = 1,000,000µg.

4,687µg = 4.687mg.

So yes, you have it exactly right.

i calculated the iodine content of Caulerpa racemosa seaweed using titration methods with sodium thiosulfate.. but protocol says that the data must be converted to parts per million (ppm). i have searched almost everywhere on how to convert but i really cant find any formula,

got any ideas? ^^

[Mrs X]

Originally Posted by Unregistered

i calculated the iodine content of Caulerpa racemosa seaweed using titration methods with sodium thiosulfate.. but protocol says that the data must be converted to parts per million (ppm). i have searched almost everywhere on how to convert but i really cant find any formula,

got any ideas? ^^

Can you give the titration method and what numbers you got? - Also need dry weight of your sample.

hello, how do you convert the ppm i got from iodine analysis (using iodide titration method) to grams? i used 50 g of the sample. the sample was the seaweed Caulerpa racemosa.

Gee thanks for any answers, I need it tonight,

[Mrs X]

Originally Posted by Unregistered

hello, how do you convert the ppm i got from iodine analysis (using iodide titration method) to grams? i used 50 g of the sample. the sample was the seaweed Caulerpa racemosa.

Gee thanks for any answers, I need it tonight,

What did you dilute your 50g to, and what was the result of your titration? Do you know how to work out the concentration of iodine in your solution from the titration results?

i diluted it with water. then i added a number of reagents, such as bromine water, h2so4, sodium sulfite, then i titrated it with sodium thiosulfate (0.005N)

[JohnS]

Originally Posted by Unregistered

i diluted it with water. then i added a number of reagents, such as bromine water, h2so4, sodium sulfite, then i titrated it with sodium thiosulfate (0.005N)

I'm not a chemist (Mrs X is) but are we overthinking this?

From the volume and normality of thiosulfate, ou can work out the total amount in moles of iodine, then convert to grams. It is totally due to the original 50 g sample. Work out grams of iodine from the titration data, divide by 50 g and multiply by 1 million to convert the fraction to parts per million.

[Mrs X]

I wouldn't think the whole 50 g was used in the titration though. Normally you'd dilute to a known amount (eg 100mL), then take 3 separate aliquots (20mL each?) and titrate each of them for an average.

OP if you are still around, and you did just use the whole 50g in one titration, your equivalents of thiosulphate used = the equivalents of iodine in your kelp.