[trichocereus]

Hi, I'm quantifying the amount of alkaloids present in a San Pedro cacti (Echinopsis pachanoi (formerly Trichocereus pachanoi)). I am not trying to look at just one alkaloid but mescaline (illegal to extract on it it's own) is the primary one. I decided to do Thin Layer Chromatography as an attempt to quantify them. I've seen other studies say they used Mescaline Sulphate as their standard, something I obviously again can't get my hands on because it's illegal. What should I do? I don't know another way to quantify the alkaloids present and I can't get my hands on the standard; what else can I do? Can I use something else as the standard?