Samples were placed onto glass slides and treated for the indicated amount
of time. Black: 50 mm KPi buffer (100 mL) was treated with plasma. Immediately
after treatment, the samples (20 mL) were mixed with 180 mL A. dest.
and H2O2 concentrations determined using the Spectroquant Hydrogen Peroxide
kit (Merck) and photometrical measurements at 455 nm. Red: direct
conversion of guaiacol (5 mm) with plasma was achieved by treating KPi
buffer (100 mL) containing 0.1 UmL@1 HRP. Production of tetraguaiacol was
followed at l=470 nm. The data shown represent means of three independent
experiments.