One of the advantageous features of the stop-and-go method is that the users can analyze the data many hours later or even the next day because once the assay stalls, the signals remain the same afterward. This is not the case when the NaOH concentration is above the NH4OAc concentration, because in the presence of palladium, the solutions turned blue (Figure ). The UV-vis spectrum of the solution in well E5 (200 nM PdCl2, 1.6 M NaOH, 360 mM NH4OAc) suggested that the blue color may be due to the formation of resazurin by the palladium-O2 catalysis. Therefore, although these reaction conditions showed expected signal immediately after the assay was complete, we recommend that users do not add more NaOH than NH4OAc. The order of addition. For convenience, the deallylation should start as soon as the last solution is added to wells.