I have been trying to find out how this method works, but the papers I find are related to the application of this technique and not to the basic principle of it. Any helpful link will also help me so much. Thank you!
may I suggest one of my favorite textbooks on ion chromatography to answer this question? Authored by Hamish Small, the book is called "Ion Chromatography".
Another excellent source coming with a ton of application information is the "Handbook of Ion Chromatography" authored by Joachim Weiss.
Maybe the library of your research institute has a copy of either or both?