Extraction-spectrophotometric determination of oxalate in urine and blood serum

Abstract

An extraction-spectrophotometric method is described for the determination of oxalate, based on the formation of a mixed ligand vanadium(V)-mandelohydroxamic acid-oxalate complex. The complex was extracted into a solution of trioctylmethylammonium chloride (Adogen 446) in toluene and the absorbance measured at 535 nm. The experimental variables and interferences in this determination were studied. The detection limit is 0.5 µg ml^–1 and the range of application is between 2 and 8 µg ml^–1. The method was applied to the determination of oxalate in urine and blood serum.