Profiling clinically important metabolites in human urine by capillary electrophoresis and electrochemical detection

Clinically important metabolic markers, including alditols, carbohydrates, and amino acids, were profiled directly in urine by capillary electrophoresis with electrochemical (EC) detection via oxidation at a copper electrode. CE in strongly basic buffers was found to provide an effective means with which to achieve the separation of these compounds with the buffer pH being the most important factor governing the separation. EC detection at a copper electrode provided a convenient means for detecting all of these species with sensitivity usually down to the femtomole level. Most important, both the CE separation and EC detection were performed directly on the urine samples without extensive sample cleanup and with no analyte derivatization required. Specific compounds that were able to be identified and quantitated included glucose, galactose, creatinine, and uric acid. All were found to be present at normal levels in urine samples from healthy subjects.