Bhumireddy Sudarshan Reddy

Can anyone suggest a simple calculation procedure to prepare any solution in terms of ppm ?

I am very confident and experienced enough in preparing the solutions up to ppm level when it is a SOLID, but I am confused in the case of LIQUIDS, say for example Hexadecane (hydrocarbon) has 0.77g/cm3 Density, I have to prepare 1 ppm of the same.  In terms of calculations and unit conversions can any one provide  a simple procedure. Though, there are several online calculators are available I would like to know..!

Thanks.

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After when you prepared 1000 ppm solution. you can prepare further low concentration from 1000ppm using the formula.

Required concentration in ppm from stock solution 1000ppm = C1V1 =C2V2

C Represent Concentration and V represent Volume

Popular Answers (1)

Algae International Berhad

g/m3 = 1 mg/L =1 ppm

1 g/cm3 = 1,000,000 g/m3

0.77g/cm3 = 770,000 g/m3

770,000 g/m3 = 770,000 ppm

To prepare 1ppm of hexadecane in 1000 ml of water,

M1V1 = M2V2

(770000 ppm)V1 = (1ppm) 1000ml

V1 = 0.0013ml or 1.3 µl

If u don't have the micro-pipette, u can prepare 1000ppm of hexadecane first then can dilute to 100, 10 and finally 1 ppm.

  • 10.2 Units of Measure

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All Answers (27)

Divide the mass you need to add to the vial by the density to get the volume you need, then measure it out with a micropipette if you have access to one. It helps to pre-weigh the volumetric flask you are using as well so you can get the accurate mass added. If you don't have access to micropipettes, I'd add dropwise using a Pasteur pipette to get as close as you can - again if you are using a pre-weighed volumetric flask, you can still get the accurate mass added. This only works if you don't need exactly 1 ppm of course; if 1.2 ppm will do for instance. If you do, then I think you'll need to buy a micropipette.

Algae International Berhad

g/m3 = 1 mg/L =1 ppm

1 g/cm3 = 1,000,000 g/m3

0.77g/cm3 = 770,000 g/m3

770,000 g/m3 = 770,000 ppm

To prepare 1ppm of hexadecane in 1000 ml of water,

M1V1 = M2V2

(770000 ppm)V1 = (1ppm) 1000ml

V1 = 0.0013ml or 1.3 µl

If u don't have the micro-pipette, u can prepare 1000ppm of hexadecane first then can dilute to 100, 10 and finally 1 ppm.

  • 10.2 Units of Measure

    10 06.pdf

     54.36 KB

Hi!

Although it is commonly used, ppm should only refer to dimensionless units (ug/g, uL/L), that means that g/m3 should NOT be called ppm. But it is usually done (http://en.wikipedia.org/wiki/Parts-per_notation#Improper_applications)

In the case of liquids, the thing is simpler than with solids, 1 ppm = 1uL/L That means, one microlitre of hexadecane in one litre of total solvent + sample.

Usually, it's very hard and will lead to a lot of error doing it straight away. You should better prepare something like 1000ppm and then dilute to 1ppm in several steps.

If you would like to do it in weight, then you should weight 1ug and put it in 1g of total solvent + sample.

The result of doing it in volume and in weight is NOT the same, you should specify which option you have chosen. Even if you choose the improper g/m3, you should specify it for any other person to understand it. If you can choose, using SI units is always much better.

Good luck!

Institute of Cancer Research

Alejandro is right. Do serial dilution.  1ppm =  1mg per L

1) Prepare 10,000 ppm Stock Solution

=  10,000mg per liter = 10g per liter =  1g per 100mL

e.g.  weigh 1 gram of solute and add solvent up to the 100mL mark in a volumetric flask

As hexadecane is volatile, it might be better to weigh 1g as you might have considerable loses due to evaporation.

2) Perform 1 to 100 serial dilution (e.g. 1mL to 100mL)

e.g.  10,000 ppm  to 100 ppm,  then 100 ppm to 1ppm

You can adjust the total volumes accordingly.

Heavy water plant, Tuticorin

Whatever be the density of the solution, weigh 0.1g of the substance in beaker and transfer the content to 100mL standard measring flask using your medium or solvent. Make up to the mark.  It will result 1000 ppm of the solution.

From this stock you can dilute to desired ppm of the solution.

For example, if you want 100ml 1ppm solution, take 0.1mL  from stock(1000 ppm) and make up to 100ml in standard measuring flask using desired solvent.

Let me try to draw these threads together:

As Alejandro Carrasco correctly points out, ppm should be dimensionless. However, you do need to decide whether you want your ppm to be volume:volume (sometimes referred to as ppmv) or mass:mass.

Volume is straightforward as described by various previous respondents. For mass you need to either weigh the liquid (funny how often people forget that you can weigh liquid) or take account of its density when calculating the volume to dispense. In either case you need to make sure you are trying to weigh/dispense quantities that are sufficiently large for the accuracy you need and make up stock solutions as required.

When pipetting volatile liquids (e.g. hexane) it is wise to change the pipette tip after each operation. This is because most pipettors work by air displacement. The presence of residual volatiles in the tip produce inconsistent results if they are used for more than one operation. As an exercise, try pipetting, say, 1 ml of hexane and observing the level of the liquid in the tip on two successive operations. Alternatively use a positive displacement pipettor (i.e. one with a plunger), though these tend to be expensive.

Respected Sir(s)/Madam(s),

Thank you so much, i have been unlighted  with all your explanations.

Thank you one and all once again.

National Centre for Antarctic and Ocean Research

1 mg/Liter = 1 ppm

But You can prepared stock solution 1gram/1 Liter=1000 ppm.

From this you can prepare desirable concentration using V1N1=V2N2.

V1= Desired Volume

N1= Desired Concentration

V2= ?

N1= Stock Concentration

Hence, use V2= V1N1/N2

Hope you understand

SRISTI Society for Research and Initiatives for Sustainable Technologies and Institutions

1mg per litre that called as 1 ppm

Kohat University of Science and Technology

How I will prepare the 500 ppm solution of Ag+, using AgNO3.

Will I follow the same thing mg/L ?

Institute of Cancer Research

The mass required for Ag must be corrected by multiplying (MM of AgNO3 /MM of Ag+) as you are weighing AgNO3 instead of Ag+

e.g.

for 1L solution = 500mg Ag = 0.5 g Ag+ x ( 169.87 / 107.868 )= 0.787 g AgNO3

I hope that helps.

Salaamoallykum. If samples have no molecular formulas use one mg per liter is called one ppm. if you have molecular formulas like NaCl. use and formula ppm = molecular weight divided by atomic weight of that you want to prepare for solution.

Thans

Universidade NOVA de Lisboa

Please note that ppm concentration stands for mg solute / kg solution.

Only for sufficiently dilute aqueous solutions, the solution density can be taken as that of water. For this kind of concentration calculation it is commonly assumed that the density of water is 1 g/cm3.

I remark that concentrations are typically given in a solute to solution basis; not in a solute to solvent basis. A rare exception to this trend is molality (mol solute / kg solvent).

Shivaji University, Kolhapur

Simple calculation procedure to prepare any solution in terms of ppm involves weighing 1 mg and dissolving in 1000ml of the solvent i.e. 1ppm solution.. Once you prepare stock solution the other solutions can be prepared. use formula,

M1V1=M2V2

Salaamoallykum. If no formula just use 1mg per litre is equal to one ppm. If formula is there use molecular weight divided by atomic weight for you want to prepare . Like sodium chloride. Molecular weight is 58.5 divide by 23 atomic weight of sodium you have 2.54g. When you dissolve in liter of distilled water you will get 1000 ppm of sodium solution. Same for others

Jagannath University - Bangladesh

1ppm =  1mg per L

weigh 1 gram of solute and add solvent up to the 100mL mark in a volumetric flask

Jomo Kenyatta University of Agriculture and Technology

Suppose RMM of salt/RMM of Target elements) is x, then weigh x and devolve one litre and will 1000ppm. From prepare sub solutions

1ppm = 1mg/L

10ppm = 1mg/100 ml

100 ppm = 1 mg/10 ml

and vise versa

1.......Use the standard dilution formula in general chemistry, i.e., Volume(1) x Concentration(1) = Volume(2) x Concentration(2). Make sure all your units are the same. Thus, you can either change 1000 ppm to ppb (1000 ppm x 1000 ppb/1ppm) = 1000000 ppb or you can change the ppb needed to ppm. So, you have a stock solution of 1000000 ppb (concentration 1), and you want to know what volume(1) to dilute to make a stock solution of whatever volume you want (for example 100 mL). Thus, if you want 5 ppb, the formula is ? mL(1) x 1000000 ppb(1) = 100 mL(2) x 5 ppb(2). Solve for ? and you have the volume you should add to a 100 mL volumetric flask. Bring it up to volume and you're good to go. Note that this formula is universal but from a practical aspect you would only be pipetting 0.0005 mL of your stock to get your 5 ppb. Thus, using a 1000 ppm stock to start is not practical. I suggest that you make a 1 ppm stock and start from there. Take 0.1 mL of your 1000 ppm stock and dilute it to 100 mL (use a volumetric flask for accuracy and convenience). Then, re-run the calculation using the dilution formula. To avoid waste, and depending on the volumes you need, you can proportionally cut the volume of all your stocks.

Masinde Muliro University of Science and Technology

Anand Agricultural University

1 ppm= 1 mg/L

10 ppm = 1 mg100 ml

100 ppm = 1 mg/10 ml

So one can calculate accordingly

1000ppm=1g/1L

Then dilute by formulla

M1V1=M2V2

1 mg/L = 1 ug/mL = 1 ppm

M1V1=M2V2

or you can use serial dilution

There are two methods for preparation of ppm solution.

1- If you do not have molecular formulas. just take solid samples one gram of unknown sample in one liter of deionized water. you will get 1000 ppm of that unknown solution.

2-If you have samples with molecular weight. Example. Sodium chloride you want to prepare sodium 1000 ppm. use the formula. as

Ppm sodium or mg/L = Molecular weight NaCl = 23+35.45= 58.45

= Molecular weight /Atomic weight of Sodium

1000ppm of Na = 58.45/23

= 2.54g of NaCl in 1000 ml Deionized water

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