Research On Sample Pre-treatment Technology And HPLC Analysis Of POPs

In the analysis of persistent organic pollutants (POPs), thepre-treatments of samples are very important processes, which determinethe sensitivity and feasibility of an analytical method. They may not onlyaffect the final analytical results directly but also affect the lifetime of thedetection instrument. Traditional pre-treatments of samples such as solidphase extraction, Soxhlet extraction, liquid-liquid extraction, need manyoperations and waste lots of time, and the plentiful organic solvent maypollute the environment. In order to develop the simple, rapid and efficientpre-treatment processes of samples, we have carried out the followinginnovative works.1. Magnetic microspheres confined ionic liquid was synthesized bycovalent bonding N-methylimidazolium on magnetic microspheres. Thefunctionalized magnetic microspheres were characterized by Fouriertransform infrared (FT-IR) spectra, thermogravimetric analysis (TGA) andscanning electron microscopy (SEM). The prepared material was used forthe preconcentration of three chlorophenols (CPs) in water combined withhigh-performance liquid chromatography (HPLC). Several conditions thatmay affect the extraction efficiency such as standing time, eluent and itsvolume, sample pH and volume were optimized. Under the optimalconditions, good recoveries (70.3-88.8%) were achieved with satisfactoryrelative standard deviations (RSDs) less than 6.0%. The limits of detectionfor the three CPs were 0.20-0.35μg L^-1. The results indicated that the ionicliquid-functionalized magnetic microspheres are with significant promisefor the analysis of CPs in environmental samples.2. C18-functionalized magnetic microspheres synthesized in athree-stage system and characterized by Fourier transform infrared (FTIR)spectroscopy and SEM were applied for clean-up and enrichment ofpolycyclic aromatic hydrocarbons (PAHs) in soil samples combined withultrasonication extraction. Magnetic soild-phase extraction (MSPE)parameters, such as elution solvents, amounts of sorbents, enrichment timeand organic modifier were optimized together with ultrasonication time and extraction solvents. Under the optimal conditions, the developed methodprovided spiked recoveries of 63.2-92.8% with RSDs of less than 6.4% andlimits of detection were 0.5-1.0 ng g^-1. This new method provides severaladvantages, such as high extraction efficiency, convenient extractionprocedure, and short analysis times.3. A readily applicable method based on extraction by aqueous non-ionicsurfactant solutions and HPLC, has been developed for the determination ofthe chlorophenols (CPs) in environmental soils. The extraction parameters:extraction time, surfactant concentration and surfactant volume wereoptimized. Under the optimized conditions, the method was applied todifferent soil samples. Fortified soils gave an average recovery between66.0 and 81.9%, with relative standard deviation of 1.0–5.5% for CPs.Results confirmed that this relatively simple procedure performedsatisfactorily in the determination of CPs in environmental solid matricesand that it can be a suitable alternative method to conventional systemseven for routine analyses.