Biochemistry of fluoroacetate poisoning. The isolation and some properties of the fluorotricarboxylic acid inhibitor of citrate metabolism - Note upon the infra-red examination of 'active’ inhibitor fractions

The infra-red spectra of several samples of ‘active’ citrates have been obtained, using a Perkin Elmer Model 21 double-beam spectrophotometer. The samples have been examined in several forms, of which a Nujol mull of the barium salt has proved the most satisfactory. Comparison of the spectra of ‘active’ and ‘inactive' samples has shown, in two cases, the presence of a weak additional band in the ‘active’ sample in the vicinity of 9⋅75 μ . This band has been assigned to the C-F stretching vibration in barium fluorocitrate. Although this assignment cannot be unequivocable until a sample of pure barium fluorocitrate has been examined for comparison, there appears little doubt that it is, in fact, accurate. This region (9⋅0 to 10⋅0 μ ) has been assigned to the C-F vibration by several workers as a result of the examination of a number of compounds (Colthup 1950; Thompson 1948; and Williams 1948). Examination of fluoroacetic acid, ethyl fluorolactate and barium fluoroacetate and barium fluorolactate shows bands which can be assigned to the C-F vibration at 9⋅33, 9⋅39, 9⋅74 and 9⋅55 μ respectively.