Catechol browning was further characterized using physiologically-relevant buffers and aminecontaining molecules under mildly alkaline conditions. Reactions consisted of 15.6 mM catechol incubated with 50 mM Pi buffer (pH 7.8), 50 mM Tris buffer (pH 7.8), 15 mM Gly, 20 mg/mL BSA, 20 mg/mL skim milk, or combinations thereof, for 96 h at 37 °C (Fig. ). All conditions exhibited browning, but with widely-varying intensities. Between the two buffers alone, the amine-containing Tris caused more pronounced browning than Pi (Figs. ). Other aminecontaining additives (Gly, BSA, skim milk) significantly enhanced browning, generally with further amplification in Pi-buffered reactions as compared to unbuffered conditions. Gly and BSA visibly enhanced browning (Figs. ), with spectral scans revealing strong shoulders or even small peaks near 330-340 nm (Figs. ). In reactions with skim milk, catechol browning was visually evident after 96 h -with a darker colour in reactions Pi-buffered reactions than in unbuffered reactions (Fig. ). However, in spectral scans, unbuffered reactions displayed higher absorbance values after 96 h -as compared to Pi-buffered reactions -likely due to milk turbidity artifacts (Fig. ); turbidity clarification during browning likely accounted for reduced absorbance under buffered conditions.