Separation of oxalate, formate and glycolate in human body fluid samples by capillary electrophoresis with contactless conductometric detection

A new method for rapid determination of toxic metabolites after methanol and ethylene glycol intoxication – oxalate, formate and glycolate in various body fluid samples (blood serum, saliva, urine, exhaled breath condensate) by capillary electrophoresis with contactless conductometric detection was developed. A selective separation of the three target analytes from other constituents present in the analyzed biological matrices was achieved in less than 6 min in a fused silica capillary of 25 μm I.D. using an electrolyte comprising 50 mM l-histidine and 50 mM 2-(N-morpholino)ethanesulfonic acid at pH 6.1. The only sample preparation was dilution with deionized water. The limits of detection were 0.4, 0.6 and 1.3 μM and limits of quantitation 1.3, 1.9 and 4.2 μM for oxalate, formate and glycolate, respectively. The method provides a simple and rapid diagnostic test in suspected intoxication and is able to distinguish the ingested liquid, based on its metabolite trace. The method presents a fast screening tool that can be applicable in clinical practice.