Photochemical determination of the solubility of oxygen in various media.
A photochemical method for determining the oxygen concentration in air-saturated non-aqueous solvents has been developed. Solutions containing a sensitizer (Rose Bengal or Methylene Blue) and 1,3-diphenylisobenzofuran (DPIBF) as an oxygen acceptor are irradiated at 546 or 633 nm and the absorbance at 404 nm is monitored. The dissolved oxygen content is found from the change in absorbance and the known 1:1 stoichiometry of addition of singlet oxygen to DPIBF. The solubilities found, accurate to +/- 6%, for oxygen in air-equilibrated solvents, are (mM): acetone, 2.37; acetonitrile, 2.42; dimethylsulfoxide, 0.33; ethanol, 1.94; N-methylformamide, 1.31. Measurements on mixed acetone-N-methylformamide solvents showed that the solubility of oxygen does not vary with solvent composition in a predictable manner.
Franco
C
C
Department of Chemistry and Biochemistry, California State University, Fullerton, CA 92634, U.S.A.
Olmsted
J
J