Application Of New Cloud Point Extraction In The Organic Pollutants Analysis

Cloud point extraction(CPE)is a new kind of preconcentration and separation technology.CPE,based on the solubility and cloud point phenomenon of aqueous solution of surfactants,causes the separation of surfactant-rich phase and an aqueous phase by changing the experimental parameters such as pH value of sample solution,concentration of surfactant,ionic strength,equilibrium temperature,equilibrium time,centrifugation time,which results in the separation of hydrophobe and hydrophile.As a method of separation and enrichment because of its simple operation,low toxicity to the environment,high extraction efficiency,high enrichment factor,security,economic and easy to hyphenation with other instruments,it has been widely used in sample pre-treatment.In this paper,we used the environmentally benign and novel CPE such as dual-cloud point extraction(dCPE)and mixed micelle cloud point extraction(MM-CPE),combination of spectral and chromatography methods for the determination of phenolic compounds,ciprofloxacin and benzylpenicillin in environment and food samples.The previous methods are time-consuming and used a lot of organic solvent,this method solved the mentioned problems.Four chapters were carried out in this paper:1.Reviewed the progress in the analysis of the research and application of cloud point extraction in environmental and food samples.2.The dual-cloud point extraction(d CPE)coupled with capillary electrophoresis(CE)to determine phenolic compounds in environment water has been studied.Non-ionic surfactant Triton X-114 as extraction reagent and sodium hydroxide solution as back-extraction reagent were chosen,the effect of experimental conditions were discussed to determine the optimal conditions of the experiment.Under the optimum conditions,the limits of detection for phenol,2,4,6-trichlorophenol and 2-nitrophenol were 0.10 μg/m L,0.15 μg/m L and 0.18μg/m L,respectively;the enrichment factor were 24.0,19.3 and 20.1,respectively;the relative standard deviation were 3.9%,2.6% and 3.3%,respectively.The developed method was successfully applied to the determination of phenolic compounds in environment water.3.A mixed micelle cloud point extraction coupled with fluorescence spectrophotometry for the detection of ciprofloxacin in environment water using mixed micelle extractant of the anionic surfactant sodium dodecyl sulfate(SDS)combined with the non-ionic surfactant Triton X-114,in the presence of sodium chloride electrolyte that can produce cloud point phenomenon and induce phase separation.The effect of experimental conditions were discussed to determine the optimal conditions of the experiment.At the optimum conditions,the resultant of ciprofloxacin repeatability expressed as the detection limit,the relative standard deviation were 0.05ng/mL and 2.2%,respectively.The recoveries of ciprofloxacin in environment water samples ranged from 96.2% to 99.1%.The presented novel method has been successfully applied to the determination of ciprofloxacin in tap water and lake water with satisfactory results.4.A novel method of mixed micelle cloud point extraction coupled with ultraviolet spectrophotometry for the detection of benzylpenicillin in milk using mixed micelle extractant of the cationic surfactant cethyl trimethylammonium bromide(CTAB)combined with the non-ionic surfactant Triton X-114.The effects of experimental conditions such as p H,concentration of surfactant,equilibration temperature and time on cloud point extraction were discussed.Under the optimum conditions,the detection limit and the relative standard deviation of benzylpenicillin were 50.0ng/m L and 2.5%,respectively.The recoveries of benzylpenicillin of milk were from 84.0% to 93.2%.The proposed novel strategy was successfully applied to the determination of benzylpenicillin in milk samples with satisfactory results.