The Research And Application Of New Solid Phase Microextraction Technique In The Analysis Of Environmental Samples

In trace analysis of environmental and biological samples,preparation of samples, purification and preconcentration havebeen major challenges for analytical chemists. Liquid-liquidextraction (LLE) and liquid-solid extraction (LSE) methods havebeen developed rapidly in recent years. They not only offer theability to separate the target analytes from the sample solution, butalso reduce, control or even eliminate the interferences originallypresent. There is also the possibility of preconcentrating andquantifying analytes at trace levels in the original sample.Nowadays, analytical chemists look to reduce the amounts ofsolvents and chemicals used in analytical experiments, sominiaturization of conventional extraction methods to minimizeanalysis time and level of consumption of chemicals isrecommended. The purpose is to develop a faster, simpler,inexpensive and more environmentally-friendly sample-preparationtechnique. In this paper, based on the analytical chemistry,separation science and environmental science, the ability ofanionic surfactant and a new magnetic nanomaterials as green andenvironmentally friendly extractant for a number of contaminants in environmental samples was studied. We found that they have strongextraction capabilit for the target analyte. UV-visiblespectrophotometry, High performance liquid chromatography andgas chromatography as the means of detection of malachite greenand plasticizers in environmental samples were established.Contents and results are as follows:1. Briefly introduced the surfactant-based extraction methods aswell as its types, applications and development. Simultaneously,the latest developments in the field and application of magneticsolid phase microextraction were given. At last, the principles ofthe research and content of this article were shown.2. A novel, fast, and efficient two-step microextraction techniquefor preconcentration and extraction of trace amounts of malachitegreen in fishpond water, river water and flesh of fish was developedusing spectrophotometry. MG with pH of6.5was extracted andmediated by the coacervation phase of anionic surfactant sodiumdodecyl benzene sulfonate. The coacervation phase was thentrapped by diatomite bonded Fe3O4magnetic nanoparticles(DBMNPs) that can rapidly achieve two-phase separation in amagnetic field. The extracted surfactant-rich phase was dilutedwith ethanol and its absorbance was measured at624nm. A numberof important parameters affecting extraction efficiency, such asvolume of extraction solvent, amount of salt, pH, amount of DBMNPs,equilibration temperature and time, were investigated. Thecalibration graph was linear for MG ranging from2ng mL1to180ngmL1in the initial solution, with r2=0.9994(n=10). The detectionlimit based on three times the standard deviation of the blank (3Sb) was0.67ng mL1and the relative standard deviation for20ng mL1of MG was1.12%(n=5). The method was applied to determine thetrace amounts of MG from fishpond water, river water and flesh offish.3. A novel and easy two-step microextraction techniquecombining anionic surfactant coacervation phase (CAP) extractionand dispersive microsolid-phase extraction (D-μ-SPE) wasdeveloped for the high-performance liquidchromatography ultraviolet detection to determination ofphthalate esters (PEs) in water samples. The method started withthe phase separation of sodium dodecylbenzenesulfonic acid(SDBSA) obtained by adding NaCl, whereas the target analytes wereextracted in the CAP. The CAP was then retrieved usingdiatomaceous earth-supported magnetite nanoparticles. Theeffects of solution acidity, SDBSA, and electrolyte concentration,extraction time, magnetic material quantity, and elution solventvolume were discussed. Under optimal extraction conditions, theextraction recoveries ranged from48.6to82.7%, and relativestandard deviations ranged from3.9to5.5%(n=10). The detectionlimits ranged from0.5to1.0ng mL1for the four PEs. The proposedmethod was used to determine the four PEs in the water samplesand recoveries between85.7and105.8%.4. In this study, diatomite bonded Fe3O4magnetic nanoparticleswere fabricated by a simple method and applied to magneticsolid-phase extraction of di-2-ethylhexyl phthalate (DEHP) fromwater samples. Several parameters affecting the extractionefficiency were investigated, including the amount of sorbent,the amount of salt,pH value,the type and volume of desorption solvent,extraction time and temperature. Under the optimized conditions, asimple, effective and environmentally friendly method for thedetermination of DEHP in water was developed by coupling with gaschromatography. The whole pretreatment process was rapid, and itcan be accomplished within10min. The limits of detection for thetarget DEHP were found to be1.36ng mL1. The recoveries in threekinds of water samples: tap water, bottled water and river waterrecoveries were in the range90.8-97%,94.8-95.8%and84.4-95.8%with the RSDs less than3.16%. This method was successfullyapplied to the analysis of DEHP in water samples.