14 replies to this topic

[chandch]

Hi all
  I am trying to calculate 1 ppm, 100 pmm for cis-3- hexenyl acetate solution (98%). FW is 142.2 and density is 0.897. Can anybody help me how to calculate ppm.

Thank you

Edited by chandch, 11 December 2012 - 10:52 AM.

[pito]

chandch, on 11 December 2012 - 10:33 AM, said:

Hi all
  I am trying to calculate 1 ppm, 100 pmm for hexenyl acetate solution (98%). Can anybody help me how to calculate ppm.

Thank you

Do you know what ppm means?

and you mean 100ppm right, not 100pmm?

[chandch]

Hi
It's parts per million. Could you please help me how I calculate ppm's

[pito]

chandch, on 11 December 2012 - 10:37 AM, said:

Hi
It's parts per million. Could you please help me how I calculate ppm's

well, if you know what it means,then why cant you calculate it?

100 ppm means 100 parts per million , so 100parts of your subtance in a total of 1 million parts, meaning:
100 parts your substance + 999 900 parts solution.

I am assuming its a powder form?
Meaning it is mass in liquid.

If we use water (then 1kg=+-1l)
We can say (in general):

ppm = 1g/m³ = 1mg/L

If you thus make 1 liter you need 1mg of 100% cis-3- hexenyl acetate solution, but yours is 98%, so you would need a bit more (1,02mg).

[chandch]

Hi. It's in liquid form. The FW is 142.2 and relative density is 0.897 g/cm3 which is 897 kg/m3. So do I need to take 10 µl cis-3-hexenyl acetate and 990 µl solvent to make 100 ppm

Thank you

Edited by chandch, 11 December 2012 - 11:21 AM.

[bob1]

chandch, on 11 December 2012 - 11:20 AM, said:

So do I need to take 10 µl cis-3-hexenyl acetate and 990 µl solvent to make 100 ppm

No - that's 1 part per 100 (10 in 1000)... you need to add some zeros on the end of the solvent.

[pito]

chandch, on 11 December 2012 - 11:20 AM, said:

Hi. It's in liquid form. The FW is 142.2 and relative density is 0.897 g/cm3 which is 897 kg/m3. So do I need to take 10 µl cis-3-hexenyl acetate and 990 µl solvent to make 100 ppm

Thank you

oh my bad, did not see that.


0.897 g/cm3
and
1 mL = 1 cm3

so 0,897grams per ml.
And you need 1,02mgrams..
So how many ml do you need?

Edited by pito, 11 December 2012 - 12:34 PM.

[chandch]

Is it 1.13 ml? But How can I calculate 10 and 100 ppm from my original liquid,. Could you please explain.

Thank you

Edited by chandch, 11 December 2012 - 11:50 AM.

[pito]

chandch, on 11 December 2012 - 11:49 AM, said:

Is it 1.13 ml? But How can I calculate 10 and 100 ppm from my original liquid,. Could you please explain.

Thank you

?
Well I just explained how to calculate the 100ppm
see:
If we use water (then 1kg=+-1l)
We can say (in general):

ppm = 1g/m³ = 1mg/L

If you thus make 1 liter you need 1mg of 100% cis-3- hexenyl acetate solution, but yours is 98%, so you would need a bit more (1,02mg).

and the previous post.

So if you know how to make 100ppm, you should be able to make 10ppm too..

[chandch]

For example, so my liquid is 0.897 g/cm3 is 0.897 g/ml. So I need 100 ppm. If I take 1.02 ml and put in 998.98 ml solvent which is 100 ppm. Am I right? or If I take 0.51 ml and 499.49 ml solvent, so it is 100 ppm. am I right?

[pito]

chandch, on 11 December 2012 - 12:12 PM, said:

For example, so my liquid is 0.897 g/cm3 is 0.897 g/ml. So I need 100 ppm. If I take 1.02 ml and put in 998.98 ml solvent which is 100 ppm. Am I right? or If I take 0.51 ml and 499.49 ml solvent, so it is 100 ppm. am I right?

If you take 1,02ml, you have= 1,02ml x 0,897 g/ml = 0,914 grams (its a bit less then 1, you need to recalculate it.. (I rounded the numbers))
I just noticed a mistake, you need 1 mgrams not 1gram!

So 1 gram is 1000 ppm more then 1mg.

So if you take 1 gram (1,02ml) and add this in 998,98ml , totaling 1 gram in 1000ml or 1gram in 1 liter, you have 1000ppm = 1000g/m³ = 1000mg/L (remember that: ppm = 1g/m³ = 1mg/L)

So to have 1000pm, you dont need 1 gram, but 0,1 gram.


I hope there are not mistakes this time.

But its pretty simple in the end:

1 ppm means 1 part per million, and you know that 1 ppm = 1g/m³ = 1mg/L (or 1ppm = 1mg/kg = 1μg/g)
So you should be able to figure it out yourself now.

[chandch]

Thank you.

[pito]

chandch, on 12 December 2012 - 12:31 AM, said:

Thank you.

Just make sure you understand the logic behind it.
There is no point in memorising formulas.

An re-calculate it, its possible I might an error somewhere.

[prabhubct]

1mg/10⁶ mg (PPM)


Does density of solutions needs consideration? some solutions have less volume/kg other higher.

Edited by prabhubct, 12 December 2012 - 11:09 AM.

[pito]

prabhubct, on 12 December 2012 - 11:08 AM, said:

1mg/10⁶ mg (PPM)


Does density of solutions needs consideration? some solutions have less volume/kg other higher.

Yes it matters.

If you work with a solution and not a powder for example, it matters.

Its the "substance/powder" that matters, not the fluid in wich it is dissolved.