Dear Amit,

     100% of anything (e.g., a rock, soil, a litre, or even cubic km, of seawater) is, by definition, all of it. If one divided it into a million equal parts each of those parts is, again, by definition a millionth, or a part per million of the whole. Furthermore, the sum of all of the parts per million (a million of them) would of course add up to the whole, or 100%. Therefore, 

100% = 1,000,000 ppm                  (1)

dividing both sides of equation (1) by 100 gives::

1%    = 10,000 ppm                       (2)

(i.e., 10000 ppm per percent)

This is the basis of the 10000 factor presented by those responding to your question.

Consequently, say one had 1200 ppm Ba (by weight) to convert it to weight percent one would simply divide 1200 ppm by 10000 ppm/% which gives 0.12 wt%.

In regards to the elemental analysis of soils, rocks and the like it is standard practice to report major elements (Si, Al, Fe, Mg, Ca, K, Na) and minor elements (e.g., Mn, Ti, P...though there can be some overlap) in weight percent, and often as weight percent oxide (e.g., SiO2, Al2O3, CaO, etc.). Trace elements (using your example Ba, Cr, Ni, Sc, Sr, V, Y, Zr) are variously defined as elements with concentrations < ~1000 ppm, and are generally reported in ppm (ug/g or mg/kg, depending upon whether one is strictly using SI units or not). The rationale for using ppm (mg/kg) to report trace elements vs. their wt % relates to the 'waste' of reporting 'zeros' and potential to misreading or introduce errors in transcribing data. For example, if one was comparing the Eu content of two rocks or soils, one with a concentration of 2 ppm and the other at 1 ppm, these equate to 0.0002 and 0.0001 wt %, respectively. The zeros are for some confusing, it is easier to evaluate trace elements in terms of their concentrations in ppm vs. wt %

Hope this helps clarify things for you.

(N.B., Dividing a gram into a million equal parts results in a million micrograms, i.e., a ug is a millionth of a g; similarly a millionth of a kg is a mg, hence, by weight, a

 ppm = ug/g = mg/kg

by volume, a

 ppm = ug/mL = mg/L

Just multiply the ppm values with 10000. You will get a percent values.

Weight percentage is parts per hundred so a factor 10000 larger than parts per million.

Percent to ppm :

1% = 1/100

1ppm = 1/1000000

So, one percent is equal to 10000 parts-per million:

1% = 10000ppm       So   x(ppm) = 10000 · x(%)

Best regards

M. Ouhsaine 

metals in soils are reported in PPM. which means mg/kg, while % means 10*mg/g, thus 1%=10000ppm

to get % weight, just 10000 multiple with ppm value

I can imagine that the explanations above are somewhat confusing. The factor 10'000 to convert wt% to ppm is correct, but how to do it (dividing are multiplying), depends on what you want to convert to what.

Let's give an example:

assume that a soil contains 10 ppm of an element, the concentration of that element expressed in wt.% is 10/10'000 = 0.001 wt%. to convert ppm in wt%, one should DIVIDE the ppm value by a factor 10'000.

When a soil contains 3 wt% of an element, the concentration in ppm is 3x10'000 = 30'000 ppm. To convert wt% in ppm, one should MULTIPLY the wt% value by a factor 10'000.

In some cases ,1ppm is not equal to 1mg/Kg (it depends in the specific gravity of water or density because it varies with Temperature). Anyway, if you want to convert ppm to %, simply you can multiply the result value of ppm by 10,000.

I do not agree with the comment of Zinabu Aassefa Alemu. When you want to convert ppm to % you should DEVIDE the result value of ppm by 10'000!!

1 ppm = 0.0001 %

1% = 10'000 ppm

I agree with Luc Robert Van Loon comments regarding this question.

Multiplay with 10000

Dear Amit,

     100% of anything (e.g., a rock, soil, a litre, or even cubic km, of seawater) is, by definition, all of it. If one divided it into a million equal parts each of those parts is, again, by definition a millionth, or a part per million of the whole. Furthermore, the sum of all of the parts per million (a million of them) would of course add up to the whole, or 100%. Therefore, 

100% = 1,000,000 ppm                  (1)

dividing both sides of equation (1) by 100 gives::

1%    = 10,000 ppm                       (2)

(i.e., 10000 ppm per percent)

This is the basis of the 10000 factor presented by those responding to your question.

Consequently, say one had 1200 ppm Ba (by weight) to convert it to weight percent one would simply divide 1200 ppm by 10000 ppm/% which gives 0.12 wt%.

In regards to the elemental analysis of soils, rocks and the like it is standard practice to report major elements (Si, Al, Fe, Mg, Ca, K, Na) and minor elements (e.g., Mn, Ti, P...though there can be some overlap) in weight percent, and often as weight percent oxide (e.g., SiO2, Al2O3, CaO, etc.). Trace elements (using your example Ba, Cr, Ni, Sc, Sr, V, Y, Zr) are variously defined as elements with concentrations < ~1000 ppm, and are generally reported in ppm (ug/g or mg/kg, depending upon whether one is strictly using SI units or not). The rationale for using ppm (mg/kg) to report trace elements vs. their wt % relates to the 'waste' of reporting 'zeros' and potential to misreading or introduce errors in transcribing data. For example, if one was comparing the Eu content of two rocks or soils, one with a concentration of 2 ppm and the other at 1 ppm, these equate to 0.0002 and 0.0001 wt %, respectively. The zeros are for some confusing, it is easier to evaluate trace elements in terms of their concentrations in ppm vs. wt %

Hope this helps clarify things for you.

(N.B., Dividing a gram into a million equal parts results in a million micrograms, i.e., a ug is a millionth of a g; similarly a millionth of a kg is a mg, hence, by weight, a

 ppm = ug/g = mg/kg

by volume, a

 ppm = ug/mL = mg/L

M. Duke once again clearly explained the case. I think that the discussion can be stopped at this stage.

Summarised:

To convert concentration in ppm towards wt %, divide the ppm by 10'000.

To convert wt % in ppm, multiply the wt % by 10'000

ppm is one part per one million, 10(-6), the % is one part per one hundred, 10(-2). To transfer one to another, it is necessary to divide or multiply on 10(4).

In solids the old ppm unit is equal to %weight in micrograms.  Not in gases.

This is the reason of the elimination of ppm from standard units.

https://www.researchgate.net/post/How_to_convert_ppm_to_weight_part_per_hundred_in_case_of_Major_element

Please,  deter ppm from literature. It is against the approved metrology.

All the answers are noted. I agree with the most. Can anybody explain this contradiction?

FYI, this is the book called, "Encyclopedia of Toxicology - Page 882

For which chemical was this example in the Encyclopedia of Toxicology?

Hello Luc!

It's for Hexachloroethane C2Cl6. Can you please explain how this came? Thanks

The conversion from ppm to mg/m3 is:

(ppm) × (molecular weight of the compound)/(24.45).

Thus for hexachloroethane: 1 ppm= 9.7 mg/m3.

I think it is a typing error. It should be : 1 ppm (10 mg/m3)

I think there's one missing in all the above comments.....xrf provides values of metal oxides and icp provides values of total metals....that is a appreciable difference hence the above logic of multiplying by 10000 will not work. 

Xrf has pure rock standards hence the metal is compared with 100% pure std. and the calculated value in % is given. whereas, ICP has liquid stds. which is total dissolved form of that particular metal. 

i am also tryin to find out the same query as you Mr. Amit!!!

The rule is the same for any element or fraction or polymer ( it  must be stated)

( ex; 1/2 Ca 2+,   Al2Cl6 ( dimer of AlCl3) ecc..

The XTF has a software that can give you the units in ppm or % depend of the concentration, this a matter to explore the XRF software and depend on the manufacturer, I use a Bruker and I can easily change to ppm, or % or oxides or  P2)5, K2O.

In the case of solids and liquids    ppm  =  mg/l

Not in gases. In them  it must be spicified if refers to   ml/ml   or mg/ml.

This is the reason for which  ppm has been eliminated from the approved units

.

How to convert ppm to percent

1% = 1/100

1ppm = 1/1000000

So

1ppm = 0.0001%

So to convert from ppm to percent, divide the ppm by 10000:

x(%) = x(ppm) / 10000

Example: find how many percent are in 300ppm.

x(%) = 300ppm / 10000 = 0.03%

@ Dr Amit Kumar

2%(w/w) is equavalent to what in ppm

Hi Osama,

1 % equal to 10000 ppm

2% is equivalent to 20000 ppm

how much is 0.0005 parts then ?

Please, remember that ppm has been eliminated from the International system

It may promote confusions in the case of gases.

Use always , for example: mg/l or ml/l

Nair N.A parts per what (if you insist on using that outdated system) per million, per billion, per trillion??

1% = 10,000 ppm

I would like to react to Leena P Vachasiddha a P Vachasiddha' s statement (August 2017): For conversion of XRF major elements, given as oxides, it is important not to confuse the wt-% of oxides with the wt-% of elements. Thus, it is necessary to convert the wt-% from element to oxide or the other way. Several websites provide conversion factors for this issue: e.g. the James Cook University (Australia) https://www.jcu.edu.au/advanced-analytical-centre/services-and-resources/resources-and-extras/element-to-stoichiometric-oxide-conversion-factors or others, which are easy to find, just google-searching e.g. "oxide element xrf conversion".

The calculations behind this are quite simple (stoichiometry):

e.g. the following case: calculation of the wt-% of Al (Element) from XRF-measurements, given in wt-% of Al2O3 (Oxide).

• 1st: calculate the molecular weight of the relevant oxide (e.g. Al2O3: M(Al)=26,982g/mol, M(O)=15,999g/mol, thus: M(Al2O3)=2*26,982g/mol+3*15,999g/mol=101,961g/mol.)
• 2nd: calculate the conversion factor, based on the ratio of the molecular weight of the element and the oxie (e.g. conversion factor=(M(Al)*2)/M(Al2O3)=(26,982g/mol *2) / 101,961g/mol=0,529. In this case it is important, that for each Al2O3 2 Al have to be considered in the conversion factor. For cases like e.g. SiO2 to 1Si this can be ignored.)
• 3rd: Multiply the wt-% of the Oxid with the conversion factor to calculate the wt-% of the Element (e.g. 14,73 wt-% Al2O3 * 0,529 = 7,797 wt-% of Al)

If you've identified any mistake, please contact me or comment. Best regards

Katja Schulz