| Summary: | 碩士 === 國立中興大學 === 獸醫學系暨研究所 === 94 === A simple and rapid high performance liquid chromatography method with electrochemical detection using disposable copper-nanoparticle-plated electrodes for simultaneous determination of major urolithic organic acids and creatinine is developed. Normal and urolithic human and canine urine samples were collected for direct analysis of creatinine, cystine, uric acid, oxalic acid, and citric acid without sample cleanup and derivatization process. Urinary organic acids were separated in 11 minutes with an anion exchange column using 0.1 M phosphate buffer at pH 7.5 as mobile phase. Optimal amperometric detection was achieved at low potentialwith detection limits in the nM levels and linear dynamic ranges spanning 2 to 3 orders of magnitude. The variations were between 2.5% and 6.2% in phosphate buffer and between 4.0% and 7.7% in urine, respectively. The recovery in urine ranged from 99.5% for creatinine to 86.6% for oxalic acid. Important differences in urolithic organic acid levels and profiles were unveiled among normal and urolithic urines and the urolith. The simplicity and reproducibility of this method has made a routine urine analysis possible and can be of great clinical and diagnostic importance to the study of urolithiasis and abnormal states related to excess secretion of organic acids in human and animals.
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