Analysis of urine for its ultraviolet-absorbing constituents by high-pressure anion-exchange chromatography.

An automatic, high-resolution analytic system for the quantitative determination of the ultraviolet-absorbing molecular constituents of urine and other body fluids is being developed. This system is comprised of a heated, high-pressure anion-exchange column for the separation step and a continuous-flow ultraviolet spectrophotometer for the detection step. Separation is achieved by elution with an acetate buffer of gradually increasing concentration. The total analysis time is 40 hr. Chromatograms showing the absorbance of the column effluent as a function of time are recorded by a strip-chart recorder and by a data acquisition system containing a digital voltmeter and paper tape punch. The output from the latter is then used as the input to a digital computer for analysis of the chromatogram. More than 140 chromatographic peaks have been resolved from a 2-mI. urine sample. Normal urine samples yield similar chromatograms. A variation in the diurnal cycle has been noted.