Electrochemical Nanobiosensing of Phenylalanine Using Phenylalanine Dehydrogenase Incorporated on Amino-Functionalized Mobile Crystalline Material-41

The immobilization and electrocatalytical activity of phenylalanine—dehydrogenase onto the n-propylamine functionalized mobile crystalline material 41 (MCM-41-
${\rm nPrNH}_{2}$
) was studied using cyclic voltametry (CV), differential pulse voltammetry (DPV), linear sweep voltametry (LSV) and square wave voltammetry (SQWV). For the first time, the electrode was evaluated as an electrochemical biosensor for electrooxidation and determination of phenylalanine in phosphate buffer solution, pH 7.00. CV study indicated that the oxidation process is irreversible and diffusion controlled. The experimental conditions influencing the determination of phenylalanine (Pha) were optimized and under optimal conditions, the oxidation peak current was proportional to Pha concentration in the range of 0.01–0.15
$\mu{\rm M}$
, while the detection limit (LOD) was 0.006
$\mu{\rm M}({\rm S}/{\rm N}={3})$
. The proposed method was successfully applied to determine Pha in human serum, yielding satisfactory results. The spiked recoveries were in the range of (95.1%–104.2%).