Dear Researchers!

You should be careful while preparing solutions. In fact if you weight a given mass and dissolve it into the desired volume, the final volume will be either greater or lesser than expected and consequently the final concentration will not be exact.

So, you should weight the solute (let say 10 mg in this case), dissolve it in a small quantity of appropriate solvent (using a beaker preferably) then transfer the solution into a 10 mL volumetric flask and complete the volume mark.

Regards!

NOBOSSE

The attached link and PPT can help you.

http://www.mgel.msstate.edu/pdf/solutions.pdf

Dry your plant extract into a powder. Then weigh 1 mg extract powder and add into 1 ml water.

Freeze dry the plant extract into powder and redissolve 1 mg of the powder in 1 mL water or solvent.

To minimize error weigh 10 mg of plant extract and dissolve it in 10 ml of solvent to prepare 1 mg/ml concentration

Dear Researcher, first find solubility of the particular extract. If it is ethanol extract it will not get dissolved in water. You can use DMSO alternatively. Solubility is extracts is main thing, if it forms suspension then it may not serve your purpose. If the extract is prepared free from solvent, you can consider it as 100%. Dissolve as per the concentration requirement you need. 

Dear Researchers!

You should be careful while preparing solutions. In fact if you weight a given mass and dissolve it into the desired volume, the final volume will be either greater or lesser than expected and consequently the final concentration will not be exact.

So, you should weight the solute (let say 10 mg in this case), dissolve it in a small quantity of appropriate solvent (using a beaker preferably) then transfer the solution into a 10 mL volumetric flask and complete the volume mark.

Regards!

NOBOSSE

I agree with above. Thanks.

In my  opinion , one of the best methods of  getting to the solution of the Objectives of  Miss Fatima is  to purify the Extract concentrate  by the  Cellulose or Silica  Flash Column  Chromatography,   collect the Fractions , do the UV scans / measurements of the  Compounds of your interest in these  fractions , separate them ,  evaporate them separately  to a small volume concentrate  , do the UV again of these two compound classes of interest  to quantitate them precisely & then  weigh  them as desired . this way  you will get the known pure forms of these compounds  for your research purpose.  Dr Abid Aziz Ajaz.

Dear Researchers!

If you want to obtain 1 mg / ml stock solution of a plant extract You must do so as advised by Pierre Nobosse and Sonal S Patel. But, as said Sunil Kumar KN, you must take into account the solubility of the extract. Taking into account that you are interested in total phenolics and Flavonoids, can be assumed that it is an ethanol or ethanol-water extract. I recommend checking the solubility of the extract in the alcohol varying concentrations (30, 50, 70, 96). To dissolve in the water, I too would try DMSO.

If you want to obtain a stock solution, which contains 1 mg / 1 ml certain substances, it is necessary to pre-determine their concentration in the extract as advised Abid Aziz Ajaz. Good luck!

Answer given to you is good....but you have to decided how u have to made it.

If u already started your experiments then u have to decide. If NOT then during the starting experiments try to made extraction in high amount, i.e. use high amount of powdered sample and also more solvent. Also go through the following publication. If any problem facing ask me any time.

Best Wishes for ur research...

If the extract is in solution, evaporated completely solvent from the extract using a rotary evaporator or led the solution stand in the open air until total evaporation of solvent. Then weight 1 mg, 2 mg, 5 mg or 10 mg of the solid extract and dissolve it in the same volume (in mL) of adequate solvent for example dissolve 1 mg of solid extract in 1 mL of adequate solvent, etc...

1- First, a Beaker or a crucible should be brought, weighed (Assume that the weight is 100 g)

2- Transfer the extract to the Beaker

3- The solvent used in the extraction process shall be disposed of by evaporation of until the dry matter is obtained as far as possible

4- The beaker is weighed after full evaporation of the solvent (Assume that the weight is 110 gm)

5- The weight of the extract (the weight of the beaker with the extract - the weight of the empty beaker) = 110-100 = 10 g

6- The extract is dissolved in the appropriate solvent Ethyl alcohol is often used and an emulsifier may be added (the amount of the solvent is calculated to obtain the desired concentration(

To prepare different concentrations:

1- The extract is dissolved in the minimum amount of suitable solvent and then a quantitative transfer is done to a volumetric flask with a final size of 100 ml (the appropriate size for the quantity of the extract).

The concentration of the extract is calculated as follows

10gm/100ml = 10×103mg/100ml= 100 mg/ml

Different concentrations could be prepared from that stock solution

To prepare 1 mg / ml with a final volume of 100 ml

V1×C1 (before dilution) = V2×C2 (after dilution)( the concentration which we would to prepare )

? ×100 = 1×100

V1= 1×100/100= 1 ml

Take 1 ml of stock solution (Conc 100mg/ ml) and supplement with appropriate solvent to 100 ml in volumetric flask.

Consider which can dissolve the extract first (i.e. the solubility). Then freeze-dry or air dry it. After dry, 1mg/mL means weighing out 1mg of the extract and mixing it with 1mL of the solvent but to consider accuracy, you need to either weighing 100mg of the extract and mix with a small quantity of the solvent in a 100mL beaker and make up to the 100ml mark.

Best wishes!