Self-Assembly Monolayer of 3-Aminopropylmethyldiethoxysilane on Glassy Carbon Electrode for Albumin Detection

An electrochemical biosensor is fabricated for detecting albumin by self-assembling monolayer of 3-aminopropylmethyldiethoxysilane (APMDES) on the surface of glassy carbon electrode. The compact self-assembled monolayer is obtained when the self-assembling temperature is 303 K, the self-assembling time is 4 h and the concentration of APMDES is 3%. To detect albumin by means of the nanogold-promoted precipitation of silver with the optimal signal-to-noise ratio, the parameters to influence the detection current signals and the background current signals are investigated using anodic stripping voltammetry. The obtained optimal processing conditions are as follows: the gold labeling temperature is 298 K and the time is 30 min, the silver enhancement temperature is 303 K and the time is 8 min. Under the above conditions, different concentrations of BSA are detected by anodic stripping voltammetry. The results showed that the peak currents are linear to the concentration of albumin over the wide range from 0.5 to 0.05 ng/mL, and the detection limit is 0.02 ng/mL, the regress linear equation is I (mu A) = 0.8254 + 1.4319 x C (ng/mL), R = 0.958, and the background current signals are smaller than 2.0 x 10(-7) A.