Development of a new method based on gold nanoparticles for measuring of uric acid in urine samples

Abstract

In the current work, a fast and easy method based on gold nanoparticles for the determination of uric acid in urine samples was reported. In the first stage, gold nanoparticles were synthesized using the chemical reduction method and then applied as a sensor to measure uric acid concentration based on its strong reducing property. Aims: The objectives of this study were: 1. Synthesis of the gold nanoparticles 2. Application of the synthesized nanoparticles as a sensor for determination of uric acid 3. Validation of the proposed method in the urine samples 4. Measurement of uric acid in urine samples taken from the patients with uric acid disorders. 5. Comparison of the analytical figures of merit of the current study with some other reported methods for the uric acid determination in urine samples. Method: The reagents were added in a 2.0 mL microtube in the following order: a proper volume of standard uric acid, 10 μL of 0.1 mol.L−1 phosphate buffer pH 4.0, 20 μL of 1,000 mg.L-1 Cu (NO3)2·3H2O, 42 μL of 0.1 mol.L−1 KI and 120 μL of Au NPs. Then diluted to 0.5 mL with deionized water. After 3 min, the solution was transferred into a 1.0 cm cell to record the absorbance. Results: At the obtained conditions, a linear relationship (R =0.997) was established between uric acid concentration and response intensity (ΔI) at the concentration range of 0.5−10.0 mg.L−1. The limit of detection (LOD) for the validated method was 0.2 mg.L–1. Conclusion: In this study, a simple and reliable Au NPs based method has been offered for the determination of uric acid in urine samples. The validated method is shown to be promising for uric acid analysis with some advantages such as good repeatability and fast response time property.