Research On Methods For Quick Scanning Of Pentachlorophenol

With the rapid development of modern agricultural and industrial, the problem ofenvironmental pollution is growing serious. Persistent organic pollutants, which arestable and persistent in the environment, and most of them have the three-inducedeffect （teratogenic, carcinogenic, mutagenic）, pose a potential hazard to human health.Pentachlorophenol （PCP） is a kind of persistent organic pollutants. So it is desirableto develop rapid and sensitive methods for the determination of PCP. Severalapproaches had been used to detect PCP, most of these methods are based on largeequipments, such as gas chromatography and liquid chromatography. They have broadapplicability, high accuracy results, but they are expensive, time-consuming andlabor-intensive, are not suitable for the quick determination of PCP in scanningpurposes. Therefore, novel and sensitive method with low cost is of greatsignificance.This thesis proposed two novel methods to detect PCP. One is based on theelectrochemiluminescence signal of luminol-TiO₂NTs system. Another is based onlable-free colorimetric signal of Au nanoparticles. TCBQ，as a kind of metabolites ofPCP, also was detected by the colorimeric of unmodified Au NPs. These two methods,which are simple and sensitive, support a novel way to detect PCP. The specificcontents are as follows:（1） Electrochemiluminescence of luminol on Ti/TiO₂NTs electrode and itsapplication for pentachlorophenol detection: The electrochemiluminescence behaviorof luminol-TiO₂NTs system was investigated. Luminol emits stable and intensivelight on the Ti/TiO₂NTs electrode at-0.6V, and PCP is found to be able to inhibit theECL intensity. PCP is detected based on the inhibition of ECL intensity. The proposedmethod exhibits simplity, high sensitivity and wide-range linearity （0.3pM to3mM）,with a limit of detection （LOD） of0.1pM. The mechanism of theelectrochemiluminescence of luminol-TiO₂NTs system was discussed. The effect ofmedium solution and the concentration of luminol on PCP detection were investigated.Interference experiments demonstrate this method exhibit good selectivity.（2） Lable-free colorimetric detection of PCP by using unmodified goldnanoparticles as indicator. Gold nanoparticles in a certain concentration of salt （asNaCl） would aggregate, which can lead to change of the solution color. When ssDNA absorb on gold nanoparticles, it will destroy the distribution of charge in the surfaceof the gold nanoparticles, which can protect gold nanoparticles agaist salt-inducedaggregation. However, the product of Fenton reation, named hydroxyl radical （·OH）,can damage the properties of ssDNA. And PCP was found to consume the·OH, in thisway, PCP can protect the gold nanoparticles against salt-induced aggregationindirectly.This thesis proposed a new method to detect PCP by investigating the linearrelationship of the concentration of PCP and the degree of gold nanoparticlesaggregation. This method exhibits simplity, and wide-range linearity （1nM to1mM）,and high sensitivity with a limit of detection （LOD） of0.5nM.（3） Lable-free colorimetric detection of TCBQ by using unmodified goldnanoparticles as indicator. TCBQ is a metabolite of PCP, the detection of TCBQ isalways a way of detection of PCP in vivo. Therefore, a novel and sensitive method todetect TCBQ is of great significance. TCBQ can selectly react with ssDNA containingG bases lead to the change of the properties of ssDNA. Therefore, the destroyedssDNA cannot protect gold nanoparticles agaist salt-induced aggregation. This thesisproposed a new method to detect TCBQ by investigating the linear relationship of theconcentration of TCBQ and the degree of gold nanoparticles aggregation. Thismethod exhibits simplity, and wide-range linearity （0.93nM⁹.3mM）, and highsensitivity with a limit of detection （LOD） of3nM. And interference experimentsdemonstrate this method exhit good selectivity.