This study describes a fast activated carbon fiber-solid phase microextraction (ACF-SPME) method for determining organochlorine pesticides (OCPs) in water. The pesticides in this study consist of Hexachlorobenzene (HCB) and alpha-, beta-, gamma-hexachlorocyclohexanes (HCHs). The optimal experimental procedures for the adsorption and desorption of four OCPs were evaluated. The linearity was obtained with a RSD of 20% for the OCPs studied over a range from 1.0 to 100 microg/L. The limits of detection at ng/L level were achieved with GC-MS under selected ion monitoring (SIM) acquisition mode. The proposed method was applied to the determination of OCPs concentration in tap water. The results have demonstrated the suitability of the ACF-SPME-GC-MS approach for the analysis of multi-residue OCPs in water. Compared to the commercial fiber, ACF has shown its advantages in solvent-resistance, thermal stability, and the cost. The results obtained in this study suggest that ACF is a promising choice in solid phase microextraction. 相似文献
Method 30B and the Ontario Hydro Method (OHM) were used to sample the mercury in the flue gas discharged from the seven power plants in Guizhou Province, southwest China. In order to investigate the mercury migration and transformation during coal combustion and pollution control process, the contents of mercury in coal samples, bottom ash, fly ash, and gypsum were measured. The mercury in the flue gas released into the atmosphere mainly existed in the form of Hg°. The precipitator shows a superior ability to remove Hgp (particulate mercury) from flue gas. The removal efficiency of Hg2+ by wet flue gas desulfurization (WFGD) was significantly higher than that for the other two forms of mercury. The synergistic removal efficiency of mercury by the air pollution control devices (APCDs) installed in the studied power plants is 66.69–97.56%. The Hg mass balance for the tested seven coal-fired power plants varied from 72.87% to 109.67% during the sampling time. After flue gas flowing through APCDs, most of the mercury in coal was enriched in fly ash and gypsum, with only a small portion released into the atmosphere with the flue gas. The maximum discharge source of Hg for power plants was fly ash and gypsum instead of Hg emitted with flue gas through the chimney into the atmosphere. With the continuous upgrading of APCDs, more and more mercury will be enriched in fly ash and gypsum. Extra attention should be paid to the re-release of mercury from the reutilization of by-products from APCDs.
Implications: Method 30B and the Ontario Hydro Method (OHM) were used to test the mercury concentration in the flue gas discharged from seven power plants in Guizhou Province, China. The concentrations of mercury in coal samples, bottom ash, fly ash, and gypsum were also measured. By comparison of the mercury content of different products, we found that the maximum discharge source of Hg for power plants was fly ash and gypsum, instead of Hg emitted with flue gas through the chimney into the atmosphere. With the continuous upgrading of APCDs, more and more mercury will be enriched in fly ash and gypsum. Extra attention should be paid to the re-release of mercury from the reutilization of by-products from APCDs. 相似文献