scholarly journals Conductimetric Biosensor for the Detection of Uric Acid by Immobilization Uricase on Nata de Coco Membrane—Pt Electrode

2011 ◽  
Vol 6 ◽  
pp. ACI.S7346 ◽  
Author(s):  
Ani Mulyasuryani ◽  
Arie Srihardiastutie

A conductimetric enzyme biosensor for uric acid detection has been developed. The uricase, as enzyme, is isolated from Candida utilis and immobilized on a nata de coco membrane-Pt electrode. The biosensor demonstrates a linear response to urate over the concentration range 1-6 ppm and has good selectivity properties. The response is affected by the membrane thickness and pH change in the range 7.5-9.5. The response time is three minutes in aqueous solutions and in human serum samples. Application of the biosensor to the determination of uric acid in human serum gave results that compared favourably with those obtained by medical laboratory. The operational stability of the biosensor was not less than three days and the relative error is smaller than 10%.

2015 ◽  
Vol 93 (11) ◽  
pp. 1239-1244 ◽  
Author(s):  
Emine Ülker ◽  
Muammer Kavanoz

A Pt electrode modified by polyaniline–poly(3-methylthiophene)–poly(3,3′-diaminobenzidine) was used for amperometric determination of epinephrine in a solution of NaHSO4/Na2SO4 (pH 2.0). For these studies, potentials between 0.40 and 0.50 V were applied, and the best response was obtained at 0.45 V. The limit of detection, limit of quantification, and the linear dynamic range were 1.23 × 10−4, 4.10 × 10−4, and 4.10 × 10−4 to 100.0 mmol L−1, respectively. These results were compared with determinations using Pt electrodes that were coated and uncoated with homopolymers. To check the accuracy of the developed method and the matrices interference, determination of epinephrine was performed in human serum samples using this modified electrode. The epinephrine concentrations were adjusted to 1.0 and 5.0 mmol L−1, and recovery values were calculated as 100.4% and 96.8%, respectively. It is significant that the determination of epinephrine was carried out at a lower potential (0.45 V) than the oxidation potential of epinephrine (0.65 V) without any matrix effect.


2016 ◽  
Vol 11 (2) ◽  
pp. 192
Author(s):  
Abdi Naufal Ramadhan ◽  
Luluil Maknun ◽  
Noerma Juli Azhari

The control of uric acid is important. A high level of uric acid can cause gout disease. Therefore a simple, fast, and accurate method for uric acid determination is required. In this research a conductometric biosensor has been developed by SPCE – Nata de coco for uric acid determination. The prepared biosensor was optimized to get a good performance of biosensor and it is applicable for human serum samples. The optimized variables were enzyme concentration, membrane thickness and pH solution. The various enzyme concentration were 6 μg/mL; 12 μg/mL; 18μg/mL; 24 μg/mL. The various membrane thickness were 5 μm; 10 μm; 15 μm. Meanwhile, the various pH solution were 7; 7.5; 8; 8.5; 9. The optimum enzime concentration was 18 µg/mL with the membrane thickness and pH were 5 µm and 8, respectively. The prepared biosensor can determine the uric acid concentration at range of 0 – 1.2 ppm with the sensitivity of 7.74 µS/ppm and the limit detection is 0 ppm. The biosensor was applied to uric acid detection in human serum with accuracy of 95 %.


2016 ◽  
Vol 11 (2) ◽  
pp. 192
Author(s):  
Abdi Naufal Ramadhan ◽  
Luluil Maknun ◽  
Noerma Juli Azhari

The control of uric acid is important. A high level of uric acid can cause gout disease. Therefore a simple, fast, and accurate method for uric acid determination is required. In this research a conductometric biosensor has been developed by SPCE – Nata de coco for uric acid determination. The prepared biosensor was optimized to get a good performance of biosensor and it is applicable for human serum samples. The optimized variables were enzyme concentration, membrane thickness and pH solution. The various enzyme concentration were 6 μg/mL; 12 μg/mL; 18μg/mL; 24 μg/mL. The various membrane thickness were 5 μm; 10 μm; 15 μm. Meanwhile, the various pH solution were 7; 7.5; 8; 8.5; 9. The optimum enzime concentration was 18 µg/mL with the membrane thickness and pH were 5 µm and 8, respectively. The prepared biosensor can determine the uric acid concentration at range of 0 – 1.2 ppm with the sensitivity of 7.74 µS/ppm and the limit detection is 0 ppm. The biosensor was applied to uric acid detection in human serum with accuracy of 95 %.


2019 ◽  
Vol 15 (6) ◽  
pp. 678-684
Author(s):  
Biljana Nigović ◽  
Jakov Vlak

Background: High uric acid serum level, hyperuricemia, is now associated with many diseases such as gout, chronic kidney disease, hypertension, coronary artery disease and diabetes. Febuxostat is a novel selective xanthine oxidase inhibitor approved for the treatment of hyperuricemia. Objective: The aim of this study was to develop a first analytical method for the simultaneous determination of febuxostat and uric acid. Methods: An unmodified boron-doped diamond electrode provided concurrent quantitation of drug at low levels and uric acid, which has clinical significance in the diagnosis and therapy of hyperuricemia, at relatively high concentrations. The direct square-wave voltammetric method was applied to the analysis of both analytes in human serum samples. Results: Under the optimized conditions, the linear response of peak current on febuxostat concentration was achieved in the range from 7.5 × 10-7 to 3 × 10-5 M, while uric acid showed two linear ranges of 5 × 10-6 - 5 × 10-5 M and 5 × 10-5 - 2 × 10-4 M. The method was successfully utilised for quantification of both analytes in human serum samples. Good recoveries were obtained without interference from common inorganic cations and anions as well as glucose, dopamine, ascorbic and folic acids at concentrations expected in physiological conditions. Conclusion: The great benefits of developed method are fast analysis (only 7.5 s for run), low cost and simplicity of performance.


Author(s):  
Hina Shamshad ◽  
Ali Sayqal ◽  
Jahan Zeb ◽  
Agha Zeeshan Mirza

Abstract A simple, accurate and precise RP-HPLC method was developed for the simultaneous determination of chloroquine, pyrimethamine and cetirizine hydrochloride concentrations in bulk drug and human serum. The assay was performed using a mobile phase of methanol: water (70:30) at pH of 2.8 ± 0.05 on the Purospher C-18 column with UV detection at 230 nm and rosuvastatin used as an internal standard. The retention times observed for chloroquine, pyrimethamine and cetirizine hydrochloride were 3.5, 2.5 and 5.5 minutes, respectively. The method was found to be specific for the assayed drugs showing a linear response in the concentration range of 1–100 μg mL−1 with coefficients of determination values of (r = 0.999). The method was developed and validated according to ICH guidelines. The method was used to monitor the serum samples and was found to be sensitive for therapeutic purposes, showing the potential to be a useful tool for routine analysis in laboratories.


2016 ◽  
Vol 129 ◽  
pp. 205-212 ◽  
Author(s):  
Adrian Marcelo Granero ◽  
Gastón Darío Pierini ◽  
Sebastián Noel Robledo ◽  
María Susana Di Nezio ◽  
Héctor Fernández ◽  
...  

2004 ◽  
Vol 516 (1-2) ◽  
pp. 135-140 ◽  
Author(s):  
José Luis Vı́lchez ◽  
Lilia Araujo ◽  
Avismelsi Prieto ◽  
Alberto Navalón

2003 ◽  
Vol 68 (8-9) ◽  
pp. 691-698 ◽  
Author(s):  
Milena Jelikic-Stankov ◽  
Predrag Djurdjevic ◽  
Dejan Stankov

In this work a new enzymatic method for the determination of uric acid in human serum has been developed. The method is based on the oxidative coupling reaction between the N-methyl-N-(4-aminophenyl)-3-methoxyaniline (NCP) reagent and the hydrogen ? donor reagent N-ethyl-N-(2-hydroxy-3-sulfopropyl)-3-methylaniline (TOOS), in the system involving three enzymes: uricase, peroxidase and ascorbate oxidase. Using this method uric acid could be determined in concentrations up to 1.428 mmol/L, with a relative standard deviation of up to 1.8 %. The effect of the medium pH and the NCP concentration on the linearity of the chromogen absorbance versus the uric acid concentration curve was investigated. The influence of the uricase activity on the maximum rate of uric acid oxidation was also examined. The use of the NCP reagent demonstrated a more precise and more sensitive determination of the uric acid compared to the determination with 4-aminoantipyrine (4-AA) as the coupling regent. The sensitivity of the method determined from the calibration curve was 0.71 absorbance units per mmol/L of uric acid; the limit of detection was LOD = 0.0035 mmol/L and the limit of quantification was LOQ = 0.015 mmol/L of uric acid.


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