Autoradiographs representing co-chromatography of 32P-labeled DNA products resulting from Cu2+ (30 μM)-mediated activation of dopamine (30 μM), H2O2 (30 μM) and their mixture. Similar amounts of radioactivity were of the DNA products, individually and in combination, were applied onto PEI-cellulose thin layers and resolved using two different solvent systems: system 1) D1 = 35 mM sodium phosphate, pH 6 onto a 6 cm Whatman no. 17 paper wick; D2 = 80 mM sodium phosphate, pH 6/10% acetonitrile (v/v) and system 2) D1 = 35 mM sodium phosphate, pH 6 onto a 6 cm Whatman no. 17 paper wick; D2 = 0.9:1 (v/v) isopropyl alcohol:4M ammonium hydroxide.