| Dioxin-like chemicals (DLCs), including polychlorinated dibenzo-p- dioxins (PCDDs), biphenyls (PCBs) and dibenzofurans (PCDFs), represent a large group of compounds. They are ubiquitous environmental pollutants which resistance to biological and chemical degradation, high bioaccumulate and biomagnify in the food chain. Exposure to DLCs has been observed to produce a variety of effects, such as tumor promotion, lethality, birth defect, immunotoxicity, hepatoxicity and so on. So to strengthen the monitoring of DLCs is necessary.High resolution gas chromatography-High resolution mass spectrometry (HRGC/HRMS) is considered as the gold standard for theidentificati-on and quantitation of DLCs, its procedures are very costly and time-consuming.Therefore, a variety of rapid and inexpensive screening bioa-ssays capable of detecting and estimating the relative potency of comp-lex mixtures of DLCs have been developed.Here we present a new method Binding Protection Mediated PCR assay(BPM-PCR) based on the mechanism of action of DLCs and the arl hydrocarbon receptor (AhR), a ligand-dependent factor which mediates both the effects of these chemicals. And then a new sample pre-treatment technologies has been established by SE-SPE- degradation of AHH.1. Soxhlet Extraction(SE)-Solid Phase Extraction( SPE )– degradation of AHH pre-treatment assay for extraction and purification of the dioxin-like chemicals in environmental samplesObjection: A novel pre-treatment assay was established to extract and purify dioxin-like chemicals.Method: the fly ash of burned garbage was used as the research model. First,it was extracted with acetone by soxhlet extraction ,purified and enriched by solid phase extraction.And then the purified liquid was divided two parts(sample 1 and sample 2).Sample 1 was analyzed by HPLC-fluorescene detection under the extraction wave length of 246nm and emission wave length of 431nm.The Bap in the fly ash of burned garbage was 1.52ug/g. The BAP of sample 2 was degraded by the AHH,and the degraded liquid was analyzed by HPLC- fluorescene detection under the extraction wave length of 246nm and emission wave length of 431nm.The experiment condition were optimized.Results:The BAP in the fly ash of burned garbage was degraded 85 percent or more during 30 minutes when temperature is 28 centigrade Conclusion: SE-SEF degradation of the AHH is a rapid, simple and cost-effective method to screen the TCDD.2. BPM-PCR assay for detection of DLCs in environmental samples Objection: To detect the TEQs of DLCs in the environmental samples using BPM-PCR. Methods: We detected the TEQs of DLCs in the fly ash of burned garbage. After the extraction, concentration and purification, the samples were dissolved in DMSO and analyzed by BPM-PCR. The results were compared with those of the HRGC/HRMS method. Results: The TCDD concentration of 1:1000 diluted extracts from two samples analyzed by BPM-PCR were 3.517×10-11mol/L and 4.022×10-10 mol/L respectively. The TEQs of two samples were 1.133μg TEQ/kg and 12.952μg TEQ/kg respectively. The TEQs by BPM-PCR were 1.42 and 2.13 times higher than those by HRGC/HRMS. Conclusion: The results from the pre-treatment assay by SE-SPE degradation of the AHH and BPM-PCR assay were near to those of HRGC/HRMS method.In general, the pre-treatment assay by SE-SPE degradation of the AHH and BPM-PCR assay is a novel and valid bioanalytical method to detect the dioxin-like chemicals. It can be used to prescreen DLCs in environmental samples due to its consistency with the other methods, with extremely low cost. BPM-PCR can either evaluate the biological and toxicological effects of dioxin or be carried out easily in the field. It is not necessary to culture cell or prepare antibody or isotope labeling for BPM-PCR, and detection time is only 4 to 5 hours. The reagents are commercial available and experiment can be performed in most of the lab. |
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