| With the rising of public awareness for environment protection, analysis of various pollutants in the environment attracts people’s attention greatly. Organic matters are part of the environmental pollutants which cannot be ignored, but the concentration of some organic pollutants in samples are very low. Therefore, extraction and enrichment pretreatment step are essential in the analysis of trace organic pollutants. In the sample pretreatment of trace analyte, the common method is analyte extraction by adsorption material. This paper started with sorption material and summarized the common sorption material. The analysis method based on the sorbents is briefly introduced, and its applications in determination of organic compounds were reviewed in this paper. At the same time, the electromagnetic induction heating was introduced in connection with the thermal desorption process.The Fe/SiO2particles were prepared by sol-gel method and then stationary liquid PDMS was coated on Fe/SiO2particles surface with evaporation in order to prepare the Fe/SiO2/PDMS particles. Fourier infrared spectrum and thermo-gravimetric analysis were used to characterize the prepared material and the results indicated that the material has good thermal stability. In the experiment, we measured the adsorption capacity of the material on the common organic pollutants such as methyl mercury and BTEX. Thereinto, the adsorption capacity on methyl mercury reached1.20mg/L and the adsorption capacity on BTEX was greater. The results showed that the prepared Fe/SiO2/PDMS particle is a good sorption material for the extraction of methyl mercury and BTEX in water samples.To establish an online method with high sensitivity for the detection of methyl mercury in water samples, the fused quartz tube filled with adsorption material Fe/SiO2/PDMS particle was used as an enrichment column. The methyl mercury in sample solution was adsorbed on the surface of enrichment column, and then the analyte was thermally desorbed from the enrichment column and pyrolysed to Hg0in pyrolysis column by using electromagnetic induction heating technique. Subsequently, the analyte was detected by an on-line coupled atomic fluorescence detector. In the experiment, some factors affecting the enrichment process were studied and optimized. Under optimal condition, the enrichment factor obtained was108and the detection limit reached0.2ng/L. At the same time, the standard reference materials were analyzed to validate the present method and the method was successfully applied to the determination of ng/L methyl mercury in water samples. Therefore, the method could be used as a possible method for trace methyl mercury detection in water samples.To establish a simple, rapid method for the analysis of BTEX in water samples, the enrichment column was filled with the prepared Fe/SiO2/PDMS particles, afterwards the extraction and enrichment of BTEX was operated with the dynamic injection mode, and then the adsorbed BTEX was desorbed by using electromagnetic induction heating. Subsequently, the separation and determination of gaseous BTEX were processed in gas chromatography. The experimental results showed that the enrichment factor obtained was1000which made the detection limit of BTEX reached ng/L level. The method had good application value for the detection of trace BTEX in water samples.The experimental results showed that Fe/SiO2/PDMS particles was good sorbent material for methyl mercury and BTEX, at the same time good heating efficiency and heating uniformity could be obtained with the electromagnetic induction heating technique as the material was based on iron particles. Therefore, it was an effective analysis method for trace volatile organic compounds in samples with the proposed method which extraction with Fe/SiO2/PDMS particles and then thermal desorption with electromagnetic induction heating, subsequently detection with related combined technology. |
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