Concentration measurements of ozone in the 1200-300ppbv range: an intercomparison between the BNM ultraviolet standard and infrared methods

Spectrophotometric determination of ozone in solutions: Molar absorption coefficient in the visible region

A new approach for the determination of ozone concentration in solutions in organic liquids based on spectrophotometric absorbance measurements in the visible region was proposed and substantiated. The molar absorption coefficient of ozone in the absorption maximum at ~600nm is 8.0mol^-1 L cm^-1 for hydrocarbons (hexane, heptane, isooctane), CHCl₃ and CCl₄, and 5.3mol^-1 L cm^-1 for methanol and 4.5mol^-1 L cm^-1 for water (±10%). The coefficient monotonically decreases with increasing dielectric constant of the liquid. The low molar absorption coefficient allows the use of spectrophotometric measurements for determination of high ozone concentrations ranging from approximately 1·10^-2mol L^-1 up to 1.0mol L^-1.