基于石墨烯-纳米金-丝素水凝胶的高灵敏有机相酶电极检测呋喃丹

采用改进的Hummers法制备了氧化石墨烯（G01．用微波辅助丝素还原法制备了丝素还原石墨烯（SF—GR），并用红外（FT—IR）、紫外（UV—vis）和透射电镜（TEM）对SF—GR进行了表征。然后以丝素同时原位还原的石墨烯一纳米金复合水凝胶包埋酪氨酸酶fTyr）制备了新型的有机相酶电极（SF—GR—NanoAu—Tyr／GCE），在纯氯仿中对呋喃丹进行了检测。结果表明，在有机相中，丝素水凝胶能较好的保持酪氨酸酶的生物活性，GR和NanoAu促进了电子在电极界面上以及水凝胶内部的电子传递，提高了酶电极的灵敏性。在没有另外添加水或者缓冲液的情况下，酪氨酸酶的抑制率与浓度范围为1．0×10^-8～1．0×10^-12mol／L的呋喃丹呈线性关系，检测限为8．0×10^-13mol／L。该有机相酶电极制备简单，检测快速，灵敏度高，适合于有机溶剂中微量农药的定量检测。

Determination of carbofuran using a highly sensitive enzyme inhibition tyrosinase OPEE based on graphene-gold nanoparticles- silk fibroin hydrogel

Graphene oxide was prepared by the method of modified Hummers. Silk-reduced-graphene （SF-GR） was prepared using microwave-assisted silk fibroin reduction synthesis method. TEM, FT-IR and UV-vis were uti- lized to characterize SF-GR. Then, a novel highly sensitive enzymatic inhibition organic phase enzyme electrode （OPEE） was fabricated by enwrapping tyrosinase in graphene-gold nanoparticles-silk fibroin hydrogel. The SF hy- drogel provided a necessary amount of water and a biocompatible microenvironment around the enzyme molecule to stabilize its biological activity and effectively prevented its inactivation by inhibitors such as pesticides. Under op- timized conditions, the inhibition percentage of carhofuran was proportional to its concentration in the range of 1.0×10^-8to 1.0×10^-12mol/L with a detection limit of 8.0×10^-13 mol/L. Thus, the highly sensitive OPEE is a promis- ing new tool for pesticide analysis in organic solvents.