Hello,

im struggling to find a right method to measure IAA production of Trichoderma, especially to add the L-tryptophan to PDB, how to make the L-tryptophan solution? what concentration?. because I recently test with 0.1 g/L L-tryptophan solution but when I added reagen Salkowski there is no color changes at all.

is anyone has suggestions about this?

i need this for completing my study, thank you