| In recent years, the novel sample preparation method has become one of hotspots in the field of biological agents, environmental and biomedicial analysis. So far, a lot of new sample pretreatment technology containing cloud-point-extraction, liquid-phase micro-extraction, solid-phase extraction, dispersive liquid-liquid micro-extraction.In these methods referred, the cloud-point-extraction(CPE) method was usually used for the separation and enrichment of environmental and pharmaceutical samples for no organic solvent consumptions, high efficient enrichment, simple operation and no polluting. In this paper, CPE was applied to extract and preconcent of active components in traditional Chinese herbs. The method that cloud point extraction coupled with UV was established for the simultaneously determination of magnolol and honokiol; another method that cloud point extraction combined with HPLC was established for the determination of magnolol and honokiol, then various factors influencing the cloud point were investigated.In the meantime, mixed micelle-mediated extraction (MM-CPE) for the analysis of fluoroquinolones, this work involves ciprofloxacin, norfloxacin and enrofloxacin. Four chapters were carried out in this paper:Chapter one:the basic theory and the applications of CPE in the separation of active components in Chinese medicine and environment. And advantages and disadvantages of cloud point extraction has been introduced.Chapter two:A novel method of cloud point extraction-UV spectrophotometry based on using Triton X-114as an extractant, was established for simultaneously detection of two targets in traditional Chinese medicinal material:magnolol and honokiol. The effects of the pH of solution, concentrations of Tx-114, equilibrium temperature and time on the efficiency of cloud point extraction have been systematically examined. Under the optimized conditions, the detection limits were2.5μg/L,1.0μg/L for magnolol and honokiol, respectively. This process was tested in traditional Chinese medicinal material, and the recoveries were98.4%-104.3%.Chapter three:A new method combined cloud-point extraction (CPE) with HPLC was established to determine honokiol and magnolol. The experimental factors influencing CPE such as pH value, Triton X-114concentrations etc. were investigated. Under optimal states, the calibration graph was linear in the range of1.0-150.0μg/L of honokiol and magnolol in the initial solution with r=0.9968,0.9982, relative standard deviation (RSD) of retention time and peak area were less than0.56%and1.78%, and the detection limit were found to be0.28μg/L,0.43μg/L, respectively. This present method was successfully tested in spiked drug samples.Chapter four:A mixed micelle-mediated cloud point extraction(MM-CPE) process has been founded for the detection of fluoroquinolone antimicrobial agents (ciprofloxacin, norfloxacin and enrofloxacin) in environmental water using mixed micellar extractant of the anionic surfactant sodium dodecyl sulfate(SDS) combined with the nonionic suefactant Triton X-114. In the presence of NaCl electrolyte that can produce cloud point phenomenon and induce phase separation, this method is called MM-CPE. The target analytes were enriched in surfactant-rich phase after separation. The optimal conditions of the MM-CPE including hydrochloric acid, concentrations of TritonX-114and SDS, inorganic salt, time of centrifugation were researed. Under the optimal states, the analytical characteristics of this method such as limit of detection, linear range, separation and enrichmental factors were obtained. The developed procedure was applicable to determine three fluoroquinolone antimicrobial agents in environmental water. |
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