THE FLUORIMETRIC MICRODETERMINATION OF GLYOXYLIC ACID IN BLOOD, URINE AND BACTERIAL EXTRACTS

1. A spectrophotofluorimetric method for the determination of glyoxylic acid in biological materials is described. 2. The method is based on the reaction between glyoxylic acid and resorcinol in acid solution, a fluorescent complex being obtained on the subsequent addition of alkali. 3. The reaction was found to be sensitive and highly specific, the minimum detectable amount of glyoxylic acid being 1.35x10(-8) mole. 4. The urinary excretion of glyoxylic acid by ten normal adults ranged from 1.4 to 4.7mg./24hr. Small but measurable amounts of glyoxylic acid were found in cell-free extracts of Pseudomonas oxalaticus OX1 grown on oxalic acid as a source of carbon. No glyoxylic acid was detected in human serum.

FLUORESCENCE POLARIZATION: MEASUREMENT WITH ULTRAVIOLET-POLARIZING FILTERS IN A SPECTROPHOTOFLUOROMETER

Ultraviolet-polarizing filters with large apertures facilitate the use of spectrophotofluorometers for measuring fluorescence polarization. Such filters (i) allow the use of polarized exciting light even in the ultraviolet region, (ii) make it possible to correct for grating anomalies which influence the observed polarization, and (iii) because of good transmission properties allow the entrance of sufficient light so that small slits and dilute solutions can be used. Under optimum conditions, polarization can be measured with a precision of +/-0.002. Results obtained are in excellent agreement with values cited elsewhere and indicate that standard spectrophotofluorometers can easily be adapted for accurate measurement of polarization.