Photodiode array ultraviolet spectrophotometric profiling of carboxylic acids in physiological fluids.

In this paper the use of a computer-controlled photodiode array spectrophotometric detector for the high-performance liquid chromatographic (HPLC) profiling of carboxylic acids in physiological fluids is reported. The ultraviolet spectrum of the flowing eluent is obtained at 6-sec intervals and is displayed as the absorbance at 190 nm. A three-dimensional (time versus wavelength versus absorbance) presentation of the HPLC profile facilitates peak identification through ultraviolet spectrum matching and relative retention time comparison with carboxylic acid standards. Several examples of HPLC urinary carboxylic acid profiles from infants with various inborn errors of metabolism are shown.