Development And Application Simple And Environment-friendly Sample Pre-treatment Methods For Detection Of Persistent Organic Pollutants

With the improvement of people’s quality of life, environment problems havebeen attracted more and more attention. POPs pollution is a problem in the mostconcern because of POPs, its mobility, bioaccumulation, and potential threat to theenvironment and human health. It is of great significance to develop effectiveanalytical techniques to monitor POPs in the environment. But the concentrations ofPOPs in environmental samples are at trace level, and the composition ofenvironmental samples is very complicated. Modern instrumental analysis cannotachieve accurate detection at such a low concentration, and cannot eliminate theinterference in the complex samples. Usually a process of pre-treatment is necessarybefore detection to concentrate target analytes. Among the methods of pre-treatment,solid phase extraction as a popular processing technology is widely used, because of itssimple operation, good extraction efficiency. This paper aims to develop novelfunctional solid-phase extraction materials for the detection of POPs in environmentalsamples. The main contents are listed as follows:1. The natural cotton was directly used in the extraction and enrichment ofpolycyclic aromatic hydrocarbons in environmental water samples, followed byHPLC-FLD detection. Natural cotton was washed with acetonitrile under ultrasoundand directly used to extract polycyclic aromatic hydrocarbons in water samples.Compared to other pretreatment adsorbent material, this method is easy to operate,does not need complicated synthetic steps, and large amounts of organic solvents.Several conditions that may affect the extraction efficiency, such as elution conditions,sample volume, and extraction time, were optimized. The method was simple,reproducible and green. Under optimized conditions, the recoveries of PAHs in watersamples were from75.74%to109.85%, the relative standard deviation was less than10%, the detection limits were0.38-2ngL-1.2. Two groups, C18and phenyl, were modified on cellulose, and this material wasused for the extraction and enrichment of polycyclic aromatic hydrocarbons inenvironmental water samples, followed by using of HPLC-FLD detection. As Phenyland C18have different ability of adsorption of PAHs, so the amounts of the modifiedC18and phenyl groups were optimized to achieve maximum extraction efficiency ofPAHs. The results showed that the adsorbent can effectively extract and enrich trace PAHs from complex environmental water samples. The method has many advantages,such as simple, reproducible, accurate and precise. Under optimal conditions, therecovery of PAHs in water samples were95.92%~115.14%, with relative standarddeviation less than7%, and the detection limits being0.004-0.4ngL-1. The detectionlimits of present method were significantly low than the detection limits of the methodwhich was established in the previous chapter, so there are some advantages in termsof detection of low concentrations PAHs in water samples.3A readily applicable method based on extraction by aqueous surfactant solutionsand HP LC, has been developed for the determination of chlorophenols (CPs) inenvironmental soils. The extraction parameters: the kind and concentration of thesolution, the amount of surfactant and extraction time were optimized. Under theoptimized conditions, the method was applied to soil samples. With average recoverybetween of74.58-97.82%, and relative standard deviation of under10%for CPs.Results confirmed that this relatively simple procedure performed satisfactorily in thedetermination of CPs in environmental solid matrices.