Glass vials for HPLC (TECHLAB, FLK 103.040) with lids (TECHLAB, FLK 101.227), septa (TECHLAB, FLK 102.797), and micro‐inserts (TECHLAB, FLK 101.263) HPLC system: Dionex P680‐HPLC system with ASI‐100 Automated Sample Injector (Dionex), RF 2000 fluorescence detector (Dionex), column system consisting of CC8/4 ND 100‐5 C18ec and CC 250/4