Specific and rapid assay of urinary oxalic acid using high-performance liquid chromatography.
A high-performance liquid chromatographic (HPLC) method was developed to determine the levels of oxalic acid in the urine. This acid was extracted from urine with tri-n-butyl phosphate and converted into the fluorescent derivative by esterification with 9-anthryldiazomethane (ADAM). The reaction mixture containing the oxalic acid derivative can be directly chromatographed on HPLC using octadecylsilane reverse-phase column monitoring with a fluorophotometric detector. A linear relationship was observed in the range from 1 to 100 micrograms/ml of standard oxalic acid dissolved in saline. Disease-free Japanese adults excrete 23.8 +/- 9.0 mg (mean +/- SD) of oxalic acid per day. This method should prove valuable for routine measurements of urinary oxalic acid as it is accurate, simple, and specific.
D000873:Anthracenes; D002851:Chromatography, High Pressure Liquid; D003124:Colorimetry; D005456:Fluorescent Dyes; D006801:Humans; D007564:Japan; D010755:Organophosphates; D010070:Oxalates / Q000302:isolation & purification / Q000652:urine*; D012016:Reference Values
D000873:Anthracenes; D005456:Fluorescent Dyes; D010755:Organophosphates; D010070:Oxalates; C027347:9-diazomethylanthracene; C009524:tributyl phosphate