A gas-liquid chromatographic method for the determination of d-glucaric acid in urine

A gas—liquid chromatographic method has been developed for the determination of D-glucaric acid in human and animal urine.The method involved a three stage procedure for the formation of a derivative of D-glucaric acid suitable for gas—liquid chromatography. The urine acidified to 0.1 M HCl was refluxed for 2 h to form an equilibrium mixture of D-glucaric acid and its lactones. The products were then converted to methyl esters with methyl alcohol and acetyl chloride and subsequently reacted with trimethylchlorosilane (TMCS) to form silylated ethers. The gas—liquid chromatographic determination of this derivative of D-glucaro-1:4-lactone gave a measure of the D-glucaric acid content in the urine.The method was found to be specific and unaffected by other likely interfering substances in the urine and capable of estimating 0.1 μg of D-glucaric acid.