Amperometric biosensor for detection of triglyceride tributyrinbased on zero point charge of activated carbon

A simple and robust single enzyme biosensor was fabricated for triglyceride (TG) detection. Graphite rods were modified with activated carbon (AC) and used as support for lipase immobilization. Chitosan (CHIT) was eventually used to create film on the bioelectrode and retain the immobilized enzyme. To extend the linear range of TG detection, AC was functionalized with carboxyl and then amine groups (AAC) to enhance the isoelectric point of AC. The constructed graphite/AAC/lipase /CHIT bioelectrode was characterized using cyclic voltammetry and field emission scanning electron microscopy (FE-SEM). The accuracy of the developed biosensor was assessed through determination of different concentrations of tributyrin (TB) in buffer solution. Linear responses were found for TB concentration in the range of 50 to 350 mg dL-1 with a detection limit of 9.9 mg dL-1. The biosensor showed good sensitivity of 0.16 μA mg-1 dL. The detected level of TG in several human serum specimens using the constructed biosensor was in good agreement with the results of an automatic biochemical analyzer. The fabricated biosensor was not affected by a number of human serum materials and showed a strong anti-interference ability. The relative standard deviation in reproducibility and repeatability tests was 3.46% and 2.94%, respectively.