Compound solubility is listed on product web pages, product information sheets or product safety and data sheets. Check the product information sheet for specific instructions for preparing stock solutions. Stock solutions are generally prepared at 10X-1000X the final required working concentration, typically in the range of 1-100 mg/mL. For dyes and indicators, we generally prepare a concentrated stock solution at 5-10 mM in the recommended solvent. The dye can then be diluted to the final desired concentration in the buffer or medium used for the application.
Solubility definitions
| Description | Solubility |
|---|---|
| Very Soluble | > 1000 mg/mL |
| Freely Soluble | 100-1000 mg/mL |
| Soluble | 33-100 mg/mL |
| Sparingly Soluble | 10-33 mg/mL |
| Slightly Soluble | 1-10 mg/mL |
| Very Slightly Soluble | 0.1-1 mg/mL |
| Practically Insoluble | < 0.1 mg/mL |
To dissolve lyophilized compounds, simply add the appropriate volume of the recommended solvent to the vial to make the desired concentration stock solution, and swirl or gently vortex to mix. Make sure the solvent comes in contact with the inside walls of the vial to fully recover the product.
Difficult to dissolve compounds can be heated to 50°C or higher (note: we do not recommend heating coelenterazine solutions), and vortexed or sonicated until completely dissolved. Some chemical compounds are just kinetically slow to dissolve. This can be especially true when the compounds are highly pure and in crystalline form. An alternative and gentler way to dissolve these compounds can be to simply rock the compound/solvent mixture in the dark overnight.
When preparing stock solutions in organic solvents such as DMF, DMSO, or alcohol for use in living cells or organisms, make a concentrated stock so that the final concentration of solvent in the working solution will not be toxic. A general guideline for immortalized cell lines is to keep the final solvent concentration below 1%; certain cell lines, primary cells or experimental organisms may be more sensitive to solvent toxicity. Similarly, for enzymatic reactions, the final concentration of solvent should be kept below 1% to avoid inhibiting enzyme activity.
Compounds dissolved in aqueous solution can be sterilized by filtration if necessary. Generally, concentrated stock solutions of compounds in organic solvents do not require sterilization, but culture medium can be sterilized by filtration after addition of the compound.
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