Based on what I know about separating organic compounds and also quantifying them, perhaps the safest bet would be to use any chromatographic estimations, such as the Liquid Chromatography-Organic carbon Detection (LC-OCD). Spectrophotometric methods might as well be available. While checking the RG for more options I happened to stumble upon the page by Dr. Richard Lamar and he has succinctly described the methods you are seeking out. He even mentioned about using specialised resins for the separation. You can definitely consult him.