Detection Of Trace Polycyclic Aromatic Hydrocarbons In Environment Water Based On Surface-Enhanced Raman Spectroscopy

Polycyclic aromatic hydrocarbons(PAHs),as widely existed aromatic organic pollutants with two or more benzene rings in the environment,are carcinogenic,teratogenic and mutagenic.They are one of the earliest known chemical carcinogens.For quite some time,based on the technologies of gas chromatography,gas chromatography-mass spectrometry and high performance liquid chromatography,many highly sensitive analytical methods for PAHs have been studied and developed.These methods have the advantages of low detection limit,accurate quantification and good stability,and high performance liquid chromatography has become the national standard method for PAHs detection.However,due to the complex operation,long time-consuming and large instalments,make them unable to meet the emergency needs of on-site monitoring.Therefore,the development of a simple,rapid and highly sensitive detection technology to analyze trace PAHs quantitatively and qualitatively has great value to China,a developing country facing severe environmental pressures.In this paper,Surface-enhanced Raman Spectroscopy(SERS)was used as the detector,and combined with sample pretreatment technology,a rapid detection method for trace PAHs in environmental water was established.The main work of this paper includes the following three parts:1.Preparation of highly sensitive SERS substrates and detection of 16 PAHsSilver nanoparticles with a particle size of 50 nm were prepared by the reduction of sodium borohydride and hydroxylamine hydrochloride,which has high stability and clean surface.16 PAHs can be detected rapidly with minimum detectable concentrations ranging from 0.1 to 100 ug/L under the optimum detection conditions.2.Developing the detection method of trace PAHs in environmental waterBased on the combination of liquid-liquid extraction and SERS(LLE-SERS),three PAHs(BaP,Pyr and Ant)were detected.Compared with the method used in 1,the minimum detectable concentrations are 5,50 and 100 ng/L respectively,which has meet the detection needs.The recoveries of the environmental waters of BaiCheng beach and the Western Ocean are between 88%and 113%.Qualitative analysis of three PAHs mixtures is also studied,which confirms the feasibility of this method.3.Establishment of a ship-borne PAHs rapid detection instrumentIn order to achieve the on-site automatic detection of PAHs in environmental water,we combined flow injection analysis(FIA)technology with SERS technology,established a ship-borne PAHs rapid detection instrument.This method has the advantages of simple operation,less time-consuming and high sensitivity.The detection process can be automatically controlled by computer program.The detector is small in size and easy to carry,which has application prospects in detection of PAHs on-site.