The vial I received appears empty.
If the products you ordered are in small quantities, and some are lyophilized to thin films on the walls of the vials, it is possible that the vials appear empty on visual inspection. Add an appropriate solvent (as indicated on the datasheet) and vortex or sonicate to ensure the compound is fully dissolved.
Waxy solids or Hygroscopic compounds
Some compounds may appear waxy or as sticky solids. Since they are difficult to 'weigh out' accurately, it is recommended that such products be dissolved directly in an appropriate solvent.
Some hygroscopic compounds will absorb water from the atmosphere and may look wet or like droplets of liquid. Such compounds need be stored in a desiccator to protect them from being exposed to the moisture in the air.
How should I dissolve the compound I purchased from you?
The information about optional solvents for our products can be found in our product datasheet. For many compounds, they are not directly soluble in water, PBS or saline, but they can be dissolved in alcohol or DMSO to make a stock solution. These stock solutions are often stable for storage and can be diluted to the desired concentration with aqueous media for use in vitro and in vivo assays. In most cases, solubility in organic solvent will be high enough to warrant dilutions of 1/500 to 1/1000 with aqueous buffer according to your experimental objective. Small amounts of residual organic solvent (for example 0.1% DMSO) do not affect most of the biological assays, however we recommend solvent controls be run alongside all experiments.
How could my peptide be dissolved?
Please reconstitute peptides with sterile water. For acidic peptides or basic peptides, small amounts of ammonium hydroxide or 10% acetic acid should facilitate dissolution. For hydrophobic or neutral peptides, a minimal amount of DMSO or DMF should first be used to solubilize the peptide. Then, add water to buffer the solution. If necessary the mixture can be sonicated briefly.
The datasheet says the compound will dissolve at a certain concentration, but I still see solid material. What should I do?
Warming the solution up to 37°C for brief periods combined with either vortexing or sonication for several minutes is often sufficient to dissolve the compound. If the solid does not dissolve after these steps, please contact our technical support for further assistance.
Compound dissolved well in DMSO stock solution, but diluting it with aqueous media, a precipitate formed.
It is common for compounds to precipitate when a DMSO stock solution is diluted with aqueous media. Most of these precipitates will re-dissolve with a few minutes of vortexing, sonication, or heating the solution in a 37°C water bath with sonication. Please ensure that the precipitate has completely re-dissolved before using the solution.
Storage and Stability
My order arrived after business hours, and was left at room temperature. However, the label on the product says it should be stored at -20°C. Is the product still good acceptable to use?
The storage temperatures that we indicate on our vial labels are the optimal conditions for long term storage. Many compounds are quite stable at warmer temperatures for short periods of time.
I received the compound and used it for the first time, how should I store leftover material?
For the majority of compounds, they could be dissolved in DMSO or other organic solvent. Their stock solution can be stored at -20°C for up to 3 months and aliquoted for sampling convenience. Several freeze/thaw cycles should not damage the activity of our small molecule products. However, in many instances the aqueous solutions of some compounds need to be made fresh and cannot be stored. For these compounds, their solution should be prepared just before use and stored no longer than 24 hours.
Your products are not sterile. Can they be used directly in my cell assay?
Our products are not sterile and we cannot guarantee that they will not contaminate your cells. However there are several precautions you can take to prevent contaminating your cell assays.
First, the culture media must contain the penicillin-streptomycin antibiotic. This will prevent the majority of contaminations. Additionally, dissolve the compounds in the pure ethanol or DMSO. These solvents are not conducive to bacterial or fungal growth, and using them will prevent contaminants in your stock solution.
Finally, if possible, your entire experiment procedure should be done under sterile conditions.