Fig. 2. (a) Time-dependent release profiles of 1 and 2 in PBS and/or pH 4 buffer solution as determined by ICP-MS. (b) Total-ion chromatograms of UPLC-QTOF-MS of cell lysates of untreated HCT116 cells and HCT116 cells treated with 1 and 3 (2 μM), respectively, for 24 h. Selected-ion chromatograms at m/z = (c) 853 and (d) 867, corresponding to the m/z of [Au(TPP–COOH)]⁺ and [Au(TPP–COOCH₃)]⁺, respectively. (e) MS recorded at t = 6.44 min of the UPLC-QTOF-MS chromatogram of cell lysates of HCT116 cells treated with 1 (2 μM) for 24 h. Inset: simulated isotopic pattern of [Au(TPP–COOH)]⁺.