Intensification of Absorption Spectra

Journal/Book: (Reprinted from Nature Vol. 198 No. 4881 p. 690 only May 18 1963). 1963;

Abstract: W. B. ELLIOTT Department of Biochemistry School of Medicine State University of New York at Buffalo Buffalo New York. G. F. DOEBBLER Research Laboratory Linde Co. Division of Union Carbide Corporation Tonawanda New York. Keilin and Hartree1 have described the sharpening and intensification of absorption spectra of hæm compounds which occurred on making the observation at liquid air temperatures. They observed that the intensification was due to light scattering by the ice crystals and could be duplicated by placing the cytochrome in a kaolin suspension. They also described a procedure for freezing the cytochrome in a glycerol-water mixture to a glass followed by devitrification by warming slightly and then refreezing the translucent material to give ten-fold intensification. Usually a five-fold intensification of absorption occurs an quick freezing a cytochrome in aqueous solution. A technique has been developed that permits approximately forty-fold intensification without additives. Small ice pellets were prepared from aqueous solution of reduced cytochromes by forcing the solution from a syringe through a fine needle (22 gauge) into a container of liquid nitrogen. Care was taken to keep the syringe in motion so that the droplets did not coalesce as they froze. The pellets formed ranged from 2 mm to a small fraction of a millimetre. . . .

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