Hello, I've seen that this question has been already asked other times on Reddit and ResearchGate but with different details. So I'm asking it too with my specifications.
I need to prepare specific culture media (nutrient broth and low-nutrient medium) with a supplement of iron. For the kind of experiments I need to do I was tasked to use FeCl3.
It has the problem that it precipitates, essentially forming rust, so what I plan to do is:
- calculate how much grams I need to reach the molarity I have to use;
- dissolve them in 1 or 2 mL of HCl 1 M to stabilize them;
- vortex and agitate the HCl solution for a while;
- add the nutrient broth to my distilled water;
- once dissolved, add the HCl solution while mixing;
- check meanwhile the pH which according to my supervisor should not exceed 5.7 and must not exceed 7 to avoid irreversible precipitation;
- use NaOH 0.1 M if required (carefully because the shift is very quick above pH = 3);
- autoclave everything and quickly prepare my vials with my strains.
I already did a small test with just 50 mL of water and NB without autoclaving, the final solution stabilized at pH = 5.49 without the need for NaOH and didn't look particularly dotted with suspension granules.
I also did another test by adding HCl before NB, the pH was 5.52 but the solution looked more torbid. I don't know if there should or shouldn't be differences.
I was told that we should use hydrated FeCl3 to get the best results, while I'm using anhydrous FeCl3 which is in storage, and once prepared a stock solution I could autoclave it and immediately use it.
Is everything right? Should I change something before proceeding with the autoclave?
I'm dubious that it might or might not perfectly work, particularly after autoclaving.
Thanks!
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