Spectrophotometer with enhanced sensitivity for uric acid detection

• Main Authors: Che Abd. Rashid, Nurfatihah, Ngajikin, Nor Hafizah, Azmi, Asrul Izam, Arsat, Rashidah, Isaak, Suhaila, Cholan, Noran Azizan, Azmi, Nur Ellina
• Format: Article
• Published: OSA - The Optical Society 2019
• Subjects: TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://eprints.utm.my/id/eprint/89551/; http://dx.doi.org/10.3788/COL201917.081701
• Institution: Universiti Teknologi Malaysia

A spectrophotometer with an LED as the light source for uric acid detection is proposed in this work. The mechanism of uric acid detection is based on energy absorbed by sodium urate, which is a chemical product of uric acid and sodium hydroxide solution. For the performance validation, comparison between the spectrophotometer with an LED and halogen lamp is carried out. Measurement results suggest that the spectrophotometer system with LED light has better sensitivity than that with halogen light. At a 460 nm wavelength, the sensitivity for the spectrophotometer with an LED is 0.0046 dL/mg, which is 73% higher than that with halogen light that records 0.0012 dL/mg. This enhanced sensitivity is attributed to the higher luminous efficacy of the LED light beam. As a result, a larger amount of flux interacts with the sample, leading to the sensitivity enhancement. The spectrophotometer with an LED is also applied for the detection of uric acid in a real human urine sample. Based on the experimental data at a 460 nm wavelength, the method manages to achieve the sensitivity of 0.0016 dL/mg, accuracy of 96.01%, limit of detection of 4.79 mg/dL, and limit of quantification of 14.52 mg/dL. These findings show that the use of LED as the input light source is promising for the spectrophotometer.