Microextraction Techniques Coupled With Chromatography For Determination Of Phenolic Compounds

Phenolic compounds, including many different kinds of species, such as phenol,alkylphenol, nitrophenol. Phenolic compounds have adverse effects on both the environment and human health; more specifically, some types of phenolic compounds may cause cancer,cellular degradation, birth defects, and interruption of hormone functions. In addition, the source of phenolic compounds is widespread such as in industry, agriculture and wastewater.Hence, it is very important to develop sensitive, rapid, simple, reliable and cheap method for enrichment and determination of phenolic compounds.Determination of analytes at trace levels in complex samples（for example, biological or contaminated water or soils） are often required for the environmental assessment and monitoring. A limited number of analytical techniques are sensitive enough for the direct determination of trace analytes in samples, for this reason, a preliminary step of the analyte isolation or enrichment prior to analysis is required in many cases. In this paper, some improvement was carried out for some microextraction technology, The proposed method only need miniaturization of equipment and easy to operation.In chapter 2, A simple magnetic solid-phase extraction method for the pre-concentration and determination of o-phenylphenol and p-phenylphenol has been developed. The magnetic iron oxide nanoparticles were analyzed by X-ray diffraction（XRD）, transmission electron microscopy（TEM） and Fourier transform-infrared spectrometry（FT-IR）. The influencing factors relevant to the solid-phase extraction such as pH, amount of sorbent, extraction time,sample volume, ionic strength and elution conditions were investigated and optimized. The enrichment factors of OPP and PPP were 50 and 48.5, respectively. The results showed that the proposed method is a simple, rapid and low-cost technique for the preconcentration and determination of OPP and PPP in aqueous samples.In chapter 3, A simple and rapid method of low-density extraction solvent-based solvent terminated dispersive liquid-liquid microextraction（ST-DLLME） was developed for determination of phenol and cresol in aqueous samples followed by gas chromatography（GC）analysis. Important parameters affecting the extraction efficiency such as pH, the volume of extraction and disperser solvents, extraction time and salting-out effect were investigatedsystematically. Under the optimized conditions, the developed method showed good linearity in the concentration range of 1¹00 ug·mL^-1（R₂≧0.9998） and the limits of detection（signal to noise ratio of 3） for all analytes were in range of 0.32⁰.38 ug·mL^-1, the precisions were varied between 5.6⁹.9 %（n=7）. The proposed method has been successfully applied to the analysis of real water samples and good spiked recoveries were achieved.In chapter 4, liquid phase microextraction combined with HPLC method has been applied for extraction and determination of nitrophenol in environmental samples. Important parameters affecting the extraction efficiency such as pH, the volume of extraction, stirring time, salting out effect and ultrasonic time were investigated systematically. The enrichment factors of the method were 79 and 63, respectively.