| Benzo(a)pyrene (BaP), also called 3,4-benzopyrene, is formed by a benzene ring fused to pyrene. Study found that BaP and BaP metabolites can combine with DNA to form BaP-DNA adducts, which may lead to errors in DNA replication and increase the risk of cancer. With the development of social industrialization, a large number of BaP produced by human activity are widely distributed in the environment through a variety of ways. Due to high chemical stability and difficult degradation, BaP in environment can migrate for a long distance, and accumulate for long time. BaP can enter into human and animal organs through digestive tract, respiratory tract, skin contact, which will pose a serious threat to human health. Therefore, it is very necessary to carry out real-time and effective detection of BaP in the environment.Due to the complex matrix and low content of target, the analysis of BaP in environmental samples usually includes two parts:pretreatment and detection, pretreatment as a key step in the process of analysis has attracted extensive research. However, most of the pretreatment methods used in the practical application are still stuck in solid phase extraction and liquid liquid extraction. In recent years, magnetic nano materials produced by the combination of magnetism and nano technology has become a research hotspot, magnetic nano material can be quickly separated by external magnetic field since the super paramagnetic, and are widely used in the pretreatment of environmental samples. BaP was selected as the research object in this paper, the functional Fe3O4 was prepared by surface modification and used to separate and enrich BaP from environmental samples, combined with instrumental analysis to establish a simple and efficient method for BaP analysis.The main research contents of this paper are as follows:(1) Preparation of fatty acids coated Fe3O4 nanoparticles for adsorption and determination of benzo(a)pyrene in environmental water samples.Mid-chain fatty acids with carbon number for the 6-11 were choosing for the modification of Fe3O4. The particle size and crystal phase of modified Fe3O4 were characterized by transmission electron microscope and X-ray diffraction, respectively. The synthesized MNPs were used as adsorbent in magnetic solid phase extraction for adsorption of BaP from water samples. The influences of adsorbent type, adsorbent dosage, the pH and ionic strength of sample matrix, temperature and sorption time on adsorption efficiency were investigated, the experimental data were fitted with isothermal adsorption mode, we found that the adsorption process corresponded well with Freundlich model (R2=0.988), and the theoretical maximum adsorption capacity was 63.90 ng/mg calculated by Langmuir model. Combined with high-performance liquid chromatography and fluorescence detection (HPLC-FLD), a simple and effective method for adsorption and determination of BaP in water samples was developed.(2) Oleic acid modified Fe3O4 and its application in the analysis of benzopyrene in cigarette smokeOleic acid coated Fe3O4 (Fe3O4@OA) was preparaed by chemical co-precipitation in aqueous media, and hydrophilic Fe3O4@OA was synthetized by adjusting the content of oleic acid. Physical characterizations of prepared Fe3O4@OA were carried out by TEM, XRD, and FT-IR. The prepared Fe3O4@OA was used as an efficient sorbent in magnetic solid phase extraction procedure for the clean-up of BaP in cigarette smoke extracts. Combined with high-performance liquid chromatography and fluorescence detection, a good linearity for the determination of BaP in the concentration range of 0.2 ～50 ng ml-1 with a regression coefficient (R2) of 0.9987 was obtained. The limit of detection (LOD) and limit of quantification (LOQ) for BaP were obtained to be 0.12 and 0.41 ng mL-1, respectively. The level of the measured BaP for 3R4F was 6.58 ng/cig, and the mean recoveries were in the range from 81.0 to 97.6% at low, medium and high spiked levels, and the relative standard deviations (RSDs) were in the range of 2.7-6.8%.(3) preparation of self-assembled magnetic molecularly imprinted polymer and its selective adsorption of benzopyrene in soilMagnetic molecularly imprinted polymers (MMIPs) using BaP as template molecule were prepared by the combination of magnetic nano material and molecular imprinting techniques, and used as MSPE adsorbents for selective separation of BaP and simultaneous elimination of complex matrices in soil samples. The adsorption conditions were optimized, and the experimental data were fitted by the isothermal adsorption model, and the adsorption process was corresponded well with Freundlich model. (R2=0.992), the maximum adsorption capacity of MMIPs was 117.65ng/mg calculated by Langmuir model. Combined with high performance liquid chromatography and fluorescence detection (HPLC-FLD), the mean recoveries of spiked samples ranged from 83.0 to 102.8% with relative standard deviations (RSD) less than 7.2%. |
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