Electrochemical Biosensor Based Novel Nanomaterial For Detection Of Contaminant In Foodstuff

Food safety issues which resulted from small molecular chemical pollutants are the most concern of all in China. To ensure human health, thus, it is necessary to prevent the market circulation of contaminated food by establishing a method which is rapid, convenient and sensitive. Nanomaterials based sensors, especially nonenzymatic biosensor and immunosensor, hold great potential on electricity, photology, mechanics, and magnetism. So, recently, the biosensors based nanomaterials are very popular in the application. Nanomaterials such as metal nanoparticles, metal nanoclusters, metal oxide nanoparticles, nanoscale semiconductor, graphene, carbon-based materials and nanocomposites enable higher sensitivity by signal amplification and introduce novel transduction principle: electrochemical signal, enhanced catalytic activity to the biosensor. Being expert, sensitive and quick-responding, biosensor is widely applied in the food analysis. In this work, therefore, hydrogen peroxide(H2O2), progesterone(P4) and histamine(HA) are detected in real samples by biosensors based different nano-materials, respectively.(1) A nanoporous Mg O based nonenzymatic electrochemical sensor for rapid screening of hydrogen peroxide in milkNanoporous Mg O was synthesized at low temperature by a hydrothermal method. And then dropped onto the surface of an electrode to establish a nonenzymatic electrochemical sensor for H2O2. The results showed that the nanoporous Mg O had extraordinary advantages for H2O2 determination compared to previously reported works. The nanoporous Mg O based electrochemical sensor exhibits good sensitivities for H2O2 in the range of 0.05-0.2 mmol/L and at the range of 0.2-10.0 mmol/L, and the limit of detection is 3.3 ?mol/L. The recovery was determined to be from 94.3% to 119.0% for spiked milk samples.(2) A dual amplified electrochemical immunosensor for progesterone: thionin-graphene oxide nanocomposite as the matrix and biotin-antibody as the labelGraphene oxide was prepared by Improved Hummers' method and then combined with thionin in virtue of intermolecular forces to enhance its intrinsic property. The antibody of progesterone was labeled with activated biotin. Thus, a dual amplified electrochemical immunosensor was structured. The proposed sensor showed good linear relation from 0.02 to 20.0 ng/m L with the limit of detection is 6.3?10-3 ng/m L in the milk. The recovery was determined to be from 84.0% to 106.0% for spiked milk samples.(3) Amperometric histamine immunosensor based on direct competitive immunoassay by one-step electrodeposition of Prussian blue-chitosan-gold nanoparticles nanocomposite films and preparation of portable histamine detection instrumentThe screen-printed carbon electrode(SPCE) was used as the electrode material due to its portable, cost-effective, and good reproducibility. SPCE based sensor conforms to the requirement of integration and microminiaturization. In this work, prussian blue(PB), chitosan(CS), gold nanoparticle(Au) were cleanly and quickly fabricated onto the SPCE based on one-step electrodeposition method. The antibody of histamine was labeled with horseradish peroxidase(HRP). Thus, amperometric histamine immunosensor based on directed competitive immunoassay was structured. The proposed sensor showed good linear relation from 0.01 to 100 ?g/m L with the limit of detection is 1.25 ng/m L in the fish. The recovery was determined to be from 92.0% to 112.5% for spiked fish samples. Furtherly, we developed a portable histamine detection instrument. The small instrument could detect histamine rapidly with semi-quantitative detection.