Application Research On Environmental Pollutants With High Performance Liquid Chromatography

Environmental pollutants spread all over the various environment in human life. With the rapid development of science and technology, more and more industrial waste, pesticide residues, domestic waste and other pollutants enter into the environment through various channels, endangering the human health and the ecological environment increasingly.As the main environmental pollutants, heavy metals and pesticide residues have become the focus of current research work. Heavy metal contamination is the result of human activities that lead to an increase of heavy metals beyond the normal range in the environment. It has led to deterioration of environmental quality and therefore has been list in the priority pollutants in the environment. Because heavy metals of different forms have different chemical and biological behavior, they have different effects on environmental quality and human health. Speciation determination of trace elements can provide more specific information about real status and impact of given elements in a system, which therefore are very necessary to reveal migration and transformation behavior as well as biochemical effects of element in the field of environmental and the life science studies. Therefore, speciation of toxic species present in the sample is very much needed. Because of the bioactivities of enantiomers being so different, they are selectively degradated and interacted in the environmental medium, the more attentions given to them now. These contaminants are generally released into the environment as racemate. Therefore, the enantiomers separation is necessary, which provides the fundamental basis on environmental behavior and ecological effects of study in the level of the enantiomers of chiral pollutants.This thesis takes metal ions and phenoxy herbicide residues as the research object, using solid phase extraction and cloud point extraction analysis different environment samples. This thesis includes three parts:In chapter 1, sample pretreatment technologies and their applications to the speciation analysis and pesticide residues analysis in environmental samples were briefly introduced. In chapter 2, the simultaneous separation and determination of Cr (III) and Cr (VI) by CPE-HPLC were investigated. Simultaneous pre-concentration of Cr (III) and Cr (VI) in sediment samples was achieved by CPE with 1-(2-thiazdylazo)-2-napthol (TAN) as the chelating agent and nonionic surfactant octylphenoxypolyethoxyethanol (Triton X-114) as the extractant. Baseline separation of the TAN chelates of Cr(III) and Cr(VI) was realized on a Waters ODS column by using a mixture of methanol-water (69:31, v/v) solution and 4.5mM CTMAB buffered with 0.03 M NaAc-HAc solution (pH 5.5) as the mobile phase at a flow rate of 0.8 mL?min-1. The precision (R.S.D.) for seven replicate injections of a mixture of 100μg?L-1 of Cr (III) and Cr (VI) were 1.2 and 0.9% for the retention time, 4.7 and 2.7% for the peak area, respectively. The proposed procedure was applied to the speciation of chromium in sediment samples with satisfactory results.In chapter 3, SPE-HPLC method was developed for investigating mecoprop and dichlorprop enantiomers and chiral separation using Chiralpak IA column were achived. Cleanert PEP cartridges were used for the enrichment and cleanup of soil samples. A mobile phase of n-hexane/ isopropanol/ TFA (98:2:0.1, v/v/v) at a flow-rate of 1 ml /min was used for initial evaluation or screening of columns. Detection and quantification was performed at 220 nm. All the experiments were carried out at 25℃. The effects of mobile phase composition, column temperature and flow rate on the enantioseparation were investigated. Based on the developed method, the detection limits based on three levels of the ratio of signal to noise were 0.2μg?mL-1 for mecoprop, 0.25μg?mL-1 for dichlorprop. Recoveries for the two pairs of enantiomers were 87.6~107.4%. Enantioselective analysis method for the two herbicides in lake sediments were developed and validated.