Linearity range enhancement in direct detection of low concentration uric acid

An enhancement of linearity range in direct detection of low concentration uric acid in visible light spectrum is reported in this paper. Direct detection method that operates without using any enzyme or reagent is utilized for the implementation of the uric acid sensor. Based on the experimental results, the analysis reveals that the operating wavelength of 850 nm in the visible light spectrum produces the optimized performances. At this wavelength, the sensor records linearity range of 2–10 mg/dL with linearity of 0.982, sensitivity of 0.038 (mg/dL)−1, resolution of 0.2632 mg/dL, limit of detection (LOD) of 0.7915 mg/dL and stability precision higher than 99%. The linearity range in this work is found superior than that reported in the previous direct detection-based uric acid sensor. This enhancement is attributed to the relatively low molar attenuation coefficient in the visible light spectrum. Besides the enhanced linearity range, the proposed sensor has the advantage of fast response time. This results from the avoidance of any enzyme or reagent in the sensing operation.