In this work, we utilize a sawhorse waveform and optimize its parameters to gain significant selectivity of Trp detection over that for Tyr. In fact, we demonstrate that our optimized conditions permit high selectivity for Trp detection over that for Tyr while maintaining high sensitivity for Trp. We also demonstrate the utility of our method in a real sample by measuring exogenous and endogenous Trp dynamics in cultured PC-12 cells and pinealocytes.