辫状螺旋碳纳米纤维类酶活性研究及其对三聚氰胺的检测

Determination of Melamine Based on the Intrinsic Peroxidase-Like Activity Plait-Like Carbon Nanocoils

合成了一种具有辫状螺旋结构的碳纳米纤维（CNCs）,发现该碳纳米纤维具有高效的类似辣根过氧化物酶（HRP）的催化活性。以3,3′,5,5′-四甲基联苯胺（TMB）和H2O2为底物对其类酶活性进行探究,结果显示该纳米酶具有良好稳定性且对TMB以及H2O2具有较强亲和力,该催化反应符合Michaelis-Menten动力学理论。同时,若在体系中加入三聚氰胺,该物质会与H2O2生成一种稳定的加成化合物,从而抑制TMB-CNCs-H2O2体系的反应,并引起反应体系中的颜色发生变化。基于以上原理,建立了一种检测三聚氰胺的新方法。体系吸光度与三聚氰胺浓度在5.070μmol/L范围内具有良好的线性关系,该方法灵敏度高,检出限低至1.8μmol/L。

In this paper,we have synthesized a helical structure of plait-like carbon nanocoils（CNCs） which have a high peroxidase-like activity. According to this character,we studied the peroxidase-like activity of CNCs on the reaction between 3,3＇, 5,5＇,-tetramethyl benzidine（TMB） and H2O2. The results show that the CNCs have a good stability and strong affinity to both TMB and H2O2, and this catalysis was also found to follow Michaelis-Menten kinetics also. Consequently,the CNCs could be used to detect hydrogen peroxide. In addition,the studies have shown that mixing of melamine and hydrogen peroxide generates an addition compound, which inhibited the TMPrCNCs-H2 02 reaction system and caused a color change of the reaction system. On the basis of this reaction and the peroxidase-like activity of CNCs, we established a method for the determination of melamine. The detection limit of melamine was as low as 1.8 μmol/L, which was quite sensitive, and this approach also has a good linear relationship ranging from 5. 0 to 70 μmol/L. Therefore, CNCs have promising potentia! for application in the field of food safety testing.