Diagnosis of ethylene glycol (antifreeze) intoxication in dogs by determination of glycolic acid in serum and urine with high pressure liquid chromatography and gas chromatography-mass spectrometry.

Abstract

A relatively fast and sensitive high pressure liquid chromatographic (HPLC) and gas chromatographic-mass spectrometric (GC/MS) method was developed for determination of glycolic acid, one of the major metabolites of ethylene glycol, in extracts of canine urine and serum. The procedure involves extraction of glycolic acid with methyl ethyl ketone and derivatization with O-p-nitrobenzyl-N,N'-diisopropylisourea (PNBDI) in ethyl acetate solution. Recovery was greater than 94% from spiked samples. Ethylene glycol and commercial antifreeze were administered to experimental dogs at different dosage levels to reproduce the naturally occurring toxicosis associated with the consumption of commercial antifreeze. Glycolic acid was determined in either the urine or serum or both from these dogs by HPLC and GC/MS. 1,3-Butanediol, a competitive inhibitor of ethylene glycol biotransformation, was administered to one dog concurrently with antifreeze. In that experiment, it was effective in decreasing glycolic acid formation and prevented acute metabolic acidosis, kidney damage, and death.