# How to prepare 100mg/ml stock solution [closed]

I want to prepare 10mL of 100mg/ml stock solution from plant extract using water. However, the plant extract I’m using have solubility problem, it can’t fully dissolved in water. So I need DMSO to dissolve it. The final concentration of DMSO has to be 1% in 100mg/ml of the plant extract.

Is this the correct way to do it ?

• Add 1000mg of plant extract powder into 10mL of DMSO (100%) as stock solution
• Take 0.1mL from stock solution and add into 9.9mL of water to get 1% DMSO + water of 100mg/ml plant extract (My working solution)

After that, I want to further get 50mg/ml and 25mg/ml from my working solution using dilution method. My question is,can I assume the concentration from 0.1mL stock solution be 100mg/ml ? And after dilution, the dmso percentage would remained the same or nah ? I got confused with this and if I’m wrong, please help correct me. Thanks in advance 😩

New contributor
Hikari95 is a new contributor to this site. Take care in asking for clarification, commenting, and answering. Check out our Code of Conduct.
• 100 mg of what? Dry extract? You said it has solubility problem.// If you have 100 mg/mL in DMSO and dissolve 0.1 mL to 10 mL, then you have 1 mg/mL. Jun 23 at 5:41
• Yes yes, dry extract. So the concentration of plant extract would be 1mg/ml ? @@ How do I prepare 100mg/ml then ? Sorry, I’m not good at this 😣 Jun 23 at 5:44
• You cannot eat the cake and have the cake. What you dilute 100 times, you must accept it gets 100 times lower concentration. As simple as law of mass conservation. Like if you give in total 100 dollars to 1 person versus to 100 persons. They would have 100 or just 1 dollars. Jun 23 at 6:02
• Note that dissolving 1000mg in 10 mL DMSO does not give 100 mg/mL. 10 mL would have to be the total volume. Jun 23 at 6:08
• Well, I am not going to teach you percentage, assuming you attended elementary school. :-) Jun 23 at 6:24