I want to use 3-indoleacetic acid for animal cell culture. As per the specification sheet (Sigma product I3750), I made a 1M stock solution in both 100% ethanol and DMSO. IAA acid dissolves well in both of these. For cell culture, I need the final concentration of IAA to be around 50mM. Also, to avoid toxicity to the growing cells, the final concentration of ethanol and DMSO should be around 0.1% or less. Now, when I do 1:10 dilution of IAA stock solution, it flocculates/precipitates. I used different types of buffers at different pH but the IAA precipitation does not stop. Can someone help me with a suggestion to avoid this problem?
If the precipitate problem happening in dilution the use of buffer is only solution as you want to restrict the ethanol concentration below 0.1%
Maybe this may work: Add a small amount of sodium hydroxide or potassium hydroxide (about 1N) directly on the IAA until the crystals dissolve. (The carboxylic group becomes deprotonated leaving a negative charge. This facilitates solvation in water). Then you add the dilution medium. Adjust a suitable pH.
Hi Guys,
Thank you for your suggestions. As mentioned by Peter, I initially dissolved it in small volume of NaOH and further diluted to required conc using PBS. Worked well.
Kudos to you both :)
cheers
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