The Ultraviolet Absorption Spectrum of Cerebrospinal Fluid: Ascorbic Versus Nucleic Acid

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Abstract
The ultraviolet (UV) absorption of the cerebrospinal fluid (CSF) was analyzed. There was a characteristic absorption spectrum with band peak at 265 m[mu] both in normal and abnormal fluids. This band in all cases was caused by ascorbic acid and not by nucleic acid. The evidence for positively identifying the 265 myu. band in CSF with ascorbic acid has been derived from an extensive investigation of a number of independent variables which affected structure, and consequently the absorption spectrum, in characteristic fashion. The unique changes of the spectrum of ascorbic acid when the pH is shifted and when different solvents are used allow effective criteria for its identification. Another test for ascorbic acid deals with its instability and the ready aerobic decomposition of ascorbic acid by catalytic oxidation which may be produced in many ways; the 265 m[mu] band responded to all decomposition tests. The properties of ascorbic acid not only help in its identification'' but also make it possible to evaluate it quantitatively in CSF. The values of ascorbic acid in CSF in a group of 80 normal and abnormal patients ranged from 0.3-4.8 mg. %.