Automatic Determination of Uric Acid in Urine in a FIA System with a Tubular Amperometric Detector

Abstract

This paper describes the use of a FIA system for the automatic determination of uric acid in urine, using a tubular amperometric detector. In this system, glassy carbon electrodes of tubular configuration were activated by successive cyclical scans from -0.30 to 2.00 V versus Ag/AgCl reference electrode in 0.50 mol.L -1 sulphuric acid solution. Samples were diluted in supporting electrolyte before analysis and no other pre-treatment was employed. Such dilution enabled the matrix effects to be reduced and therefore improving the sensitivity provided by the activation step that allows the uric acid (UA) to be detected at lower concentration levels after dilution. Uric acid determination was performed in a single channel FIA manifold, which provided reproducibility of sample transport to the detector and enabled a sampling rate of 120 samples per hour to be achieved. The tubular configuration of the cell offered robustness to the system since it was rigidly fixed to the manifold, allowing the manifold to be generalised for routine analysis application. The results obtained with the FIA system for UA determination in urine were compared with those from the enzymatic method used in clinical analysis laboratories. No statistical difference between methods was found at the 95% confidence level. Relative deviations between both methods were within ± 4% and the proposed system showed good repeatability (about 3%, n = 10).

A glassy carbon electrode modified with graphene and poly(acridine red) for sensing uric acid

“…Compared with the GR or polyAR film modified electrode, the GR-polyAR/GCE could remarkably improve the electrochemical response to UA. In contrast to previous sensors [4][5][6][7][8][9][10][16][17][18][19][20][21][22], the significant improvements of the electrochemical sensor exhibited excellent performances, such as simple preparation, fast response, high sensitivity, and good stability. To the best of our knowledge, the present strategy for the preparation of GRpolyAR/GCE for the electrochemical activity toward UA has not been studied so far.…”

“…The detection of UA is a subject of great importance because abnormal levels of UA have been linked with gout, hyperuricemia, leukemia, pneumonia and LeschNyhan syndrome [1][2][3]. In the past years, various detection methods have been used to determine UA, such as reversed phase liquid chromatography [4], fluorescence [5], and flow systems with amperometric detection employing multicommutation [6] or a single line manifold [7], and so on. Moreover, electrochemical methods, because of their specificity, fast and ease of monitoring for the determination of UA, have been reported as the feasible methods [8][9][10][11][12].…”

Pentacyanoammineferrate-Based Non-Enzymatic Electrochemical Biosensing Platform for Selective Uric Acid Measurement

“…The previous literature has reported that the range of UA concentration is between 1.49 to 4.46 mM in urine for a healthy human [ 3 ]. In the past years, various determination techniques have been used to measure UA concentration, such as reversed phase liquid chromatography [ 4 , 5 , 6 , 7 ], colorimetric and ratiometric fluorescence [ 8 ], and flow injection analysis (FIA) [ 9 ]. However, these techniques have drawbacks, as their processes are complex and time-consuming, and it is hard to miniaturize the system.…”

Electrochemical Detection of Uric Acid on Exfoliated Nanosheets of Graphitic-Like Carbon Nitride (g-C3N4) Based Sensor

“…Various standard analytical methods have been developed to determine UA such as high performance liquid chromatography (HPLC), a potentiometric enzyme electrode, flow-injection analysis, amperometry etc. [11][12][13][14][15][16] These methods have some drawbacks such as high cost, tedious sample preparation, slow measurement, unsuitability for use outside of a laboratory setting, and requirement to be performed by skilled technicians. Among these options, electrochemical sensors (ECS) are attractive for detection of bio-molecules which exhibit electrochemical activity.…”