Synthesis and Characterization of a Novel Modified Biosensor Carbon/Chitosan L-Leucine and Albumin Electrode for Bilirubin and Uric Acid Blood Detection

Bilirubin (BR) is a yellow-to-orange bile pigment produced by hemoglobin breakdown. It circulates in the blood, is absorbed by the liver, and then conjugated to form bilirubin diglucuronide. Its increased level in serum (Hyperbilirubinemia) may considered as an indication of certain diseases such as neonatal jaundice, hepatitis, and severe liver failure with cirrhosis. Thus, the monitoring of BR in plasma is clinically important. Herein, a novel carbon/chitosan paste electrode modified by L-leucine and Albumin (C/Chi-PL-BSA) is synthesized and tested for electrochemical sensitive determination of BR and Uric Acid. Significate sensitivity and important selectivity in the linear range of 1.00–150.00 μM for BR, and 10.00–600.00 μM for UA were obtained. Moreover, micromolar detection limits of 0.40 μM for BR and 1.00 μM for UA were achieved at pH13. The proposed oxidation mechanisms of BR and UA in alkaline media have been supported by DFT calculations at the B3LYP/ 6–31 G(d) level of theory. The easy preparation and high reproducibility made this electrode very appropriate in pharmaceutical preparations for the electrochemical determination of BR. Furthermore, Analyses using human serum were performed, demonstrating a high percentage of recovery.