title: Multiple screening of urolithic organic acids with copper nanoparticle-plated electrode: potential assessment of urolithic risks.
abstract: There is yet to be a reliable prediction of urolithiasis. To facilitate early diagnosis, a simple and rapid high performance liquid chromatography method with electrochemical detection using disposable copper-nanoparticle-plated electrodes (Cu(n)-SPE) was developed for multiple detection of creatinine and 4 urolithic organic acids. A total of 206 normal and urolithic human and canine urines and urolith samples were collected for direct analysis of creatinine, cystine, uric acid, oxalic acid, and citric acid without sample cleanup and derivatization processes. Urinary organic acids were separated in 11 min and were devoid of ascorbic acid interference. The detection limits (S/N>3) were at the nanomolar level with linear dynamic ranges spanning 2-3 orders of magnitude. Recoveries in urine ranged from 99.5% for creatinine to 86.5% for citric acid. The analytical variations (RSD) were less than 6.2% in phosphate buffer and 7.7% in urine. Important differences in organic acid levels/profiles between animal species and among normal and urolithic urines/urolith were unveiled and corresponded well (70-90%) with the urolithic risk in a retrospective assessment. The simplicity and reproducibility of this method using disposable Cu(n)-SPE has made routine urine analysis possible and can be of great clinical and diagnostic potential in the screening of urolithiasis and abnormal states related to excess secretion of organic acids and amino acids in humans and animals.
authors.affiliation: Veterinary Medical Teaching Hospital and Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung 402, Taiwan.
authors.forename: Chung-Wei
authors.initials: CW
authors.lastname: Yang
authors.forename: Jyh-Myng
authors.initials: JM
authors.lastname: Zen
authors.forename: Yu-Lin
authors.initials: YL
authors.lastname: Kao
authors.forename: Cheng-Teng
authors.initials: CT
authors.lastname: Hsu
authors.forename: Tung-Ching
authors.initials: TC
authors.lastname: Chung
authors.forename: Chao-Chin
authors.initials: CC
authors.lastname: Chang
authors.forename: Chi-Chung
authors.initials: CC
authors.lastname: Chou
mesh_terms: D000143:Acids / Q000652:urine*; D000818:Animals; D019343:Citric Acid / Q000652:urine; D003300:Copper / Q000737:chemistry*; D003404:Creatinine / Q000652:urine; D003553:Cystine / Q000032:analysis; D004285:Dogs; D004566:Electrodes; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry*; D019815:Oxalic Acid / Q000652:urine; D014527:Uric Acid / Q000652:urine; D016482:Urinalysis / Q000379:methods*; D052878:Urolithiasis / Q000175:diagnosis
chemical_list: D000143:Acids; D014527:Uric Acid; D019343:Citric Acid; D003553:Cystine; D003300:Copper; D019815:Oxalic Acid; D003404:Creatinine