青霉素酶-氧化苏木精修饰Au/ZnO/石墨烯基青霉素电化学传感器的研制

A Low Detection Limit Penicillin Electrochemical Biosensor Based on Penicillinase-Hematein Au/ZnO/Single Graphene Nanosheets

采用均匀沉淀法合成Zn O纳米颗粒(Zn O NPs),以Zn O NPs为种子,制备水溶性Au/Zn O异质结构。将Au/Zn O异质结构附着于离子液体功能化石墨烯(GN)复合膜上,形成一种新颖的负载型石墨烯复合材料(Au/Zn O/GN)。所构建的青霉素酶-氧化苏木精修饰Au/Zn O/GN(PH-AZG)传感器在PBS水溶液(p H=7.0)中对青霉素钠检测线性范围为2.5×10^(-14)~3.3×10^(-6)mol/L,检出限达到1.5×10^(-14)mol/L(S/N≥3)。在相同条件下制备5根PH-AZG电极,其响应电流的相对标准偏差(RSD)小于3.2%。同时,在实际牛奶制品中,本方法的检测线性范围为5×10^(-14)~5×10^(-7)mol/L,加标回收率为99.7%~101.4%,RSD为2.3%~3.5%(n=5)。结果表明,本方法对实际牛奶制品中低浓度青霉素钠的检测具有可行性。

ZnO nanoparticles（ ZnO NPs） were obtained by a direct precipitation method. With the as-prepared ZnO NPs as seeds,Au / ZnO heterostructure was synthesized by seed-mediated growth method without any surfactant,and the diameters of ZnO NPs and Au NPs were about 50 nm and 10 nm,respectively.Then ionic liquids（ ILs）,trihexyltetradecylphosphonium bis（ trifluoromethylsulfonyl） imide（ [P（ C6）3C（14）][Tf2N]）,and functionalized graphene（ GN） were prepared under room temperature. The ILs as bridges could connect Au / ZnO heterostructure to form a new kind of graphene nanocomposite,Au / ZnO / GN. Then the penicillinase and hematein were immobilized on Au / ZnO / GN. And the biosensors based on penicillinasehematein-Au / ZnO / GN（ PH-AZG） were used for detecting penicillin G. In PBS buffer solution（ p H 7. 0）,PH-AZG exhibited a detection range from 2. 5 × 10^（-14）to 3. 3 × 10^（-6）mol / L with a detection limit of 1. 5 ×10^（-14）mol / L（ S / N≥ 3）. Five PH-AZG electrodes were prepared with the same conditions,and the RSDs for their current response were less than 3. 2%. Furthermore,the standard curves were linear in the range of 5 ×10^（-14）-5 ×10^（-7）mol / L for milk. The average recoveries were 99. 7%- 101. 4% with RSDs of 2. 3%- 3. 5%（ n =5）. The method is sensitive and repeatable,and can be applied to the field of residue analysis about penicillins G with low concentration levels.