Water Environment In The Electrochemical Determination Of Pentachlorophenol And Its Metabolites And Interaction With Dna Spectroscopy Studies

Chlorinated phenolic compounds are typical environmental pollutants due to their toxicity and refractory to humans and the environment. Although there are various methods to detect these compounds, there is the lack of a fast and facile one. As a result, it is necessary to establish a sensitive and inexpensive method to detect chlorinated phenolic compounds. In this work, we choose pentachlorophenol (PCP), a typical representive of chlorphenol materials, and it’s metabolites (tetrachlorobenzoquinone, tetrachlorohydroquinone, tetrachlorocatechol and tetrachloro-o-benzoquinone) in water to detect using electrochemical methods, and study on their interaction with human tumor-related gene DNA via various spectroscopic methods. The results are summarized as follow:1. Graphene oxide was reduced to graphene in use of hydrazine hydrate, and based on this we prepared the graphene-chitosan modified glassy carbon electrode (CRG-CS/GC electrode). Transmission electron microscope (TEM) and electrochemical impedance technique were performed to characterize this modified electrode. The results revealed that graphene was fixed well on the electrode surface and the conductivity of CRG-CS/GC electrode is excellent.2. The electrochemical behavior of PCP was investigated by cyclic voltammetry(CV) and differential pulse voltammetry(DPV) on CRG-CS/GC electrode. It was found that the oxidation current at CRG-CS/GC electrode was obviously larger than that at GC electrode, indicating that the CRG-CS/GC electrode had strong adsorption ability and could promote the electron transport. Then, the CRG-CS/GC electrode with the simple, sensitive and reliable properties was developed for the determination of PCP. Using this electrode, analytical performance with the linear range from1.0×10-7to1.0×10-5mol/L and a limit of detection to2.3×10mol/L was obtained. The electrochemical sensor with the CRG-CS/GC electrode was successfully employed to detect PCP in several water samples with the recoveries of97.0-103.0%.3. We also studied the electrochemical behavior of two metabolites of PCP, tetrachlorohydroquinone and tetrachlorocatechol, on CRG-CS/GC electrode. The results suggested that the two isomers both involved diffusion-controlled oxidizing reaction, and the products could infer as tetrachlorobenzoquinone and tetrachloro-o-benzoquinone. Moreover a convenient and low-cost method was established to simultaneously determine tetrachlorohydroquinone and tetrachlorocatechol with the detection limits of8.2×10-10mol/L and1.7×10-9mol/L, respectively.4. The interactions of PCP and it’s four metabolites with human p53and C-myc DNA were investigated by ultraviolet-visble spectroscopy, fluorescence spectroscopy and circular dichroism spectroscopy. The results indicated that five compounds all interacted with the two DNA in some extent, and tetrachlorocatechol and tetrachloro-o-benzoquinone had stronger affinities. The conclution could be obtained that tetrachlorocatechol and tetrachloro-o-benzoquinone might bind in the major groove of DNA and weaken the forces of base stacking of the duplex DNA.