Hi, I have organosolv extracted Lignin that purely dissolved in DMSO due to it's insolubility in water and Ethanol. I am running FRAP assay in which i also dissolve Ascorbic acid (Standard) in DMSO but when I added FeCL3 the solution became precipitated green both standard and samples. I centrifuged the standard and sample but it effect the colour of solution, the green precipitate settled down in the bottom and now all tubes look like the same. Suggest me something where it went wrong? Here the DMSO was problem?