This is regarding the Total phenolic content assay. Initially, I used distilled water to prepare the gallic acid standard curve. But because of dissolution problems in samples in Distilled water, I used methanol instead of D water(because samples must be dissolved in the same medium as the gallic acid). But then I faced a problem. After 7.5 % Na2CO3 was added, it precipitated in the wells. (This did not occur when I used water as the solvent to prepare the dilution series.) I believe this is due to a decrease in the KSP of Na2CO3 in MeOH. I thought that if I incubated the MeOH for 30 minutes at a temperature lower than its boiling point, rather than at room temperature, this might be resolved. Did anyone face this kind of problem? what are the precautions you take to stop this kind of interference?
Results were expressed percentage w/w and calculated using following formula, Total phenolic content (% w/w) = GAE×V×D×10–6×100/W, GAE - Gallic acid equivalent (μg/ml), V - Total volume of sample (ml), D - Dilution factor, W - Sample weight (g).
https://www.kibin.com/essay-examples/a-lab-exercise-to-measure-and-calculate-total-phenolic-concentration-13UowQ7a
https://doi.org/10.1021/ed100775n
https://www.jmaterenvironsci.com/Document/vol9/vol9_N5/167-JMES-3149-Bouyahya.pdf
DOI: 10.36468/pharmaceutical-sciences.683
Regards
Nimashi Herath Same problem happened to me before, and I use ethanol instead of methanol to solve this problem.
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