*3.3. Preparation of Standard Solutions*

GAP stock solutions from previous synthesis were prepared in UPW and snSW and stored in Eppendorf tubes at −20 ◦C. Two calibration curves (with three replicates) with the di fferent water types were prepared within the range of 10–500 μM for stability and leaching assays and injected three times into the IP-RP-HPLC system with the UV detector settled at 243 nm. The standard solutions prepared in snSW were diluted with 60 mM of TBA-Br in a proportion of 1:3 prior to injection. A calibration graphic was constructed by plotting the mean peak area versus concentration.
