Electrochemical detection of creatinine using Au–Ag bimetallic nanoparticles

Abstract

The adsorption of creatinine has been examined at Au–Ag bimetallic nanoparticles. In phosphate buffer without a supporting electrolyte, both metals were oxidised within a single voltammetric peak. The oxidation peak height was inversely proportional to the creatinine concentration, indicating adsorption of the species onto the particles. The adsorption followed a Langmuir isotherm with a free energy of adsorption estimated at − 14.4 kJ mol−1. The adsorption was found to be selective in the presence of interferents such as glucose, glycine, and urea. Using the decrease in peak height creatinine could be calibrated with an LOD of 0.8 mM (defined as 3.3σ/S where σ is the standard deviation of the blank and S is the calibration gradient) and a sensitivity of 137.0 µA mM−1 (r 2 = 0.998). Recoveries of creatinine in artificial urine were in the range 92.8 to 104.5%.