Parts Per Million Conversions

PPM conversion values and serial dilutions 

 How to dilute and calculate ppm concentrations and percentage amounts.
How to convert ppm to Molarity and Molarity to ppm

 

 

PPM = parts per million

PPM is a term used in chemistry to denote a very, very low concentration of a solution. One gram in 1000 ml is 1000 ppm and one thousandth of a gram (0.001g) in 1000 ml is one ppm.

One thousanth of a gram is one milligram and 1000 ml is one liter, so that 1 ppm = 1 mg per liter = mg/Liter.
PPM is derived from the fact that the density of water is taken as 1kg/L = 1,000,000 mg/L, and 1mg/L is 1mg/1,000,000mg or one part in one million.

OBSERVE THE FOLLOWING UNITS

1 ppm = 1mg/l = 1ug /ml = 1000ug/L
ppm = ug/g =ug/ml = ng/mg = pg/ug = 10 ^-6
ppm = mg/litres of water

1 gram pure element disolved in 1000ml = 1000 ppm

PPB = Parts per billion = ug/L = ng/g = ng/ml = pg/mg = 10 ^-9

Making up 1000 ppm solutions

1. From the pure metal : weigh out accurately 1.000g of metal, dissolve in 1 : 1 conc. nitric or hydrochloric acid, and make up to the mark in 1 liter volume deionised water.

2. From a salt of the metal :
e.g. Make a 1000 ppm standard of Na using the salt NaCl.

FW of salt = 58.44g.
At. wt. of Na = 23
1g Na in relation to FW of salt = 58.44 / 23 = 2.542g.
Hence, weigh out 2.542g NaCl and dissolve in 1 liter volume to make a 1000 ppm Na standard.

3. From an acidic radical of the salt :
e.g. Make a 1000 ppm phosphate standard using the salt KH₂PO₄

FW of salt = 136.09
FW of radical PO₄ = 95
1g PO₄ in relation to FW of salt = 136.09 / 95 = 1.432g.
Hence, weigh out 1.432g KH₂PO₄ and dissolve in 1 liter volume to make a 1000 ppm PO₄ standard.
Click this link for Atomic absorption standards

Dilution Formula : C1V1 = C2V2

This equation applies to all dilution problems. C1 (initial conc) x V1 (initial volume) = C2 (final conc) x V2 (final volume)
Example : What volume of 6.00 ppm solution must be used to give 4.00 liters of a 0.100 ppm solution?
C1 = 6.00 ppm
V1 = unknown
C2 = 0.100 ppm
V2 = 4 liters = 4000 mls
V1 = (C2 x V2) / C1
     = (0.100 X 4000) / 6.00
     = 400 / 6.00 = 66.7 mls.
This means that 66.7 mls of the 6.00ppm solution diluted to a final volume of 4 liters will give a concentration of 0.100 ppm.


The Formula below can be used to calculate the the V1 component only.
req is the value you want.
req ppm x req vol
-------------------------- = no of mls for req vol
         stock

Example : Make up 50 mls vol of 25 ppm from 100 ppm standard.

25 x 50 / 100 = 12.5 mls. i.e. 12.5 mls of 100 ppm in 50 ml volume will give a 25 ppm solution

Serial dilutions

Making up 10^-1 M to 10^-5 M solutions from a 1M stock solution.

Pipette 10 ml of the 1M stock into a 100 ml volumetric flask and make up to the mark to give a 10^-1 M soln.
Now, pipette 10 ml of this 10^-1 M soln. into another 100 ml flask and make up to the mark to give a 10^-2 M soln.
Pipette again, 10 ml of this 10^-2 M soln. into yet another 100 ml flask and make up to mark to give a 10^-3 M soln.
Pipette a 10 ml of this 10^-3 M soln. into another 100 ml flask and make up to mark to give a 10^-4 M soln.
And from this 10^-4 M soln. pipette 10 ml into a 100 ml flask and make up to mark to give a final 10^-5 M solution.

Molarity to ppm

Convert molar concentration to grams per liter (Molarity x Atomic mass of solute), then convert to milligrams per liter (ppm) by multiplying by 1000.

e.g. What is the ppm concentration of calcium ion in 0.01M CaCO₃?

Molarity(M) x Atomic mass(At Wt) = grams per liter(g/l)
Atomic Mass (Wt.) of Ca = 40

0.01M x 40 =0.40 g/l
0.40g/l x 1000 = 400 mg/l = 400ppm

Note:
The FW of an ion species is equal to its concentration in ppm at 10^-3M. Fluoride has a FW of 19, hence a 10^-3M concentration is equal to 19ppm, 1M is equal to 19,000 ppm and 1ppm is equal to 5.2 x 10^-5M.
Go here for ISE molarity/ppm conversions shown in Table III.

PPM to Molarity

Convert ppm to gram based or milligram based concentration.

ppm = 1 mg solute per liter solution or
ppm = 0.001 gram per liter solution

e.g. What is the Molarity of 400ppm Ca ions in an aqueous CaCO3 solution?

Using the 0.001g/l concentration: 400ppm x 0.001g/l = 0.4g/l.
or, Divide 400 mg by 1000 to get g/l = 0.4 g/l
Now divide by the At. Mass of Ca to get Molarity.
0.4g/l divided by 40g/mol =0.01M

Using the mg/l concentration, the 40g Ca must be converted to milligrams by multiplying by 1000 to give 40,000mg.
Hence Molarity = 400ppm divided by 40,000mg/mol = 0.01M

Ppm (parts per million) to % (parts per hundred)

Divide the ppm amount by 1,000,000 and multiply by 100 to get %. e.g. :

1 ppm = 1/1,000,000 = 0.000001 = 0.0001%
10 ppm = 10/1,000,000 = 0.00001 = 0.001%
100 ppm = 100/1,000,000 = 0.0001 = 0.01%
200 ppn = 200/1,000,000 = 0.0002 = 0.02%
5000 ppm = 5000/1,000,000 = 0.005 = 0.5%
10,000 ppm = 10000/1,000,000 = 0.01 = 1.0%
20,000 ppm = 20000/1,000,000 = 0.02 = 2.0%

(Parts per hundred) % to ppm

Divide the % value by 100 and multiply by 1,000,000 to get ppm. e.g. :

1% =0.01 x 1,000,000 = 10,000 ppm
0.5% =0.0.005 x 1,000,000 = 5,000 ppm
0.1% =0.001 x 1,000,000 = 1,000 ppm
0.01% = 0.0001 x 1,000,000 = 100 ppm

 

المصدر

المصدر.