Analysis Methods Of Benzo[α]Pyrene In Soils

Environment is the space where human are living. With the development of science and technology and the improvement of people’s living standard, more and more poisonous organic pollutants are produced and released into the environment (according to statistics, more than about one hundred thousand kinds of organic compounds are released into the environment so far.). When these substances are released into the atmosphere, water and soil, if the amount, concentration and lasting time can’t meet the environment of the net force, it will pollute and damage the environment and affect human body health. The problem of environmental pollution has become increasingly serious and become a thorny problem the world facing together, which has attracted great attention of many scholars at home and abroad. Timely and effective monitoring for poisonous organic pollutants in environment and researches on the development of simple, rapid, efficient, green detection methods, have very important significance. Due to complexity and low amounts of the environmental samples, making the analytes can be measured as a appropriate forms and extraction, purification and enrichment of the analytes are necessary and important before the instrument analysis in quantitative and qualitative analysis.The main contents this paper studied are as follows:Part 1 Dispersive liquid-liquid microextraction-high performance liquid chromatography for the determination of benzo[a]pyrene in soil samplesA simple, rapid and effective method, the dispersive liquid-liquid microextraction coupled with high performance liquid chromatography, has been developed for the extraction and determination of benzo[a]pyrene (B[a]P) in environmental soil samples. The factors affecting the extraction efficiency, such as type and volume of extraction solvent and dispersive agent and extraction time were investigated and optimized. Under the optimized conditions, the linear response of this method was in the range of 0.05-20 μg/L (r=0.9913). The detection limit (LOD, S/N=3) was 0.63 μg/kg. Recoveries of spiked samples varied in the range of 81%-105.3%with the relative standard deviations (RSD) of 5.3%-9.3%(n=3). This method was successfully used for analysis of B[a]P in soil samples.Part 2 Solvent flotation combined with high performance liquid chromatography for the determination of benzo[a]pyrene in soil samplesSolvent sublation (SS), was used to separate and concentrate benzo[a]pyrene (B[a]P) from soils, and the target compound was quantitatively analyzed by high performance liquid chromatography-fluorescence detector (HPLC-FLD). In the pretreatment section, factors such as sublation solvent, gas flow rate and sublation time on the extraction efficiency were investigated. The optimized conditions of the proposed method were 5mL n-hexane,60mL/min gas flow rate and 60 min flotation time, the organic phase was transferred and dried with nitrogen and dissolved with 0.5mL acetonitrile. Under the optimized conditions, the proposed method showed good linearity in the range from 0.05 to 20 μg/L with good regression coefficient (r) of 0.9981. The limit of detection (LOD) was 0.24 μg/kg. The recoveries obtained with analyte-spiked samples were 88.2-105.3% and the relative standard deviations (RSD) were 6.1-10.7%.Part 3 Magnetic solid phase extraction of benzo[a]pyrene in soils using magnetic nanoparticles of ferroferric oxide/ multiwalled carbon nanotubes combined with high performance liquid chromatographyThe magnetic nanoparticles of ferroferric oxide/ multiwalled carbon nanotubes (Fe3O4/MWCNTs) was synthesized and used as sorbent in magnetic solid phase extraction for extraction and preconcentration of trace amount of benzo[a]pyrene (B[a]P) in soil samples with detection by high performance liquid chromatography. Fe3O4/MWCNTs was dispersed in the sample solution, could be easily separated from the solution by a magnet. The main factors affecting the extraction efficiency such as adsorbent amount, adsorption time, kind and volume of eluent have been investigated and established. The linearity was obeyed in the range of 0.05-20 μg/L, with the correlation coefficient (r) was 0.9976. The limit of detection (LOD) was 0.32μg/kg. The recoveries obtained with analyte-spiked samples were 84.5-100.7%, with the relative standard deviations (RSD) of 4.3-10.3%.