A new method, headspace solid-phase microextraction (HS-SPME) with in situ derivatization and gas chromatography-mass spectrometry (GC-MS), which was used for the determination of trace amount of pentachlorophenol (PCP) in human plasma was presented. The acetylation derivatization reaction was firstly optimized using a Doehlert design. Then a series of parameters relevant to the headspace SPME procedure, including fiber coating, extraction temperature, extraction time and salt addition, were optimized using a two-level full factorial design expanded further to a central composite design. The validation of method showed that the optimized method had good linearity (R(2)=0.999) within the concentration ranges 0.1-50.0ngml(-1), and was sensitive with the limit of detection of 0.02ngml(-1). Intra- and inter-day precision for pentachlorophenol in human plasma samples were not greater than 11.9% and 12.6%, respectively. The proposed method, to our knowledge, describes the first application of HS-SPME with GC-MS for analysis of PCP in blood plasma sample. Application of the method to real human plasma samples, PCP was successfully detected in some cases at concentration levels 1.2-6.3ngml(-1). 相似文献
Environmental Science and Pollution Research - Resource endowment and economic development of different provinces in China vary greatly, resulting in large amount of CO2 transfers. We need further... 相似文献
Here we report N2O emission results for freshwater marshes isolated from human activities at the Sanjiang Experimental Station of Marsh Wetland
Ecology in northeastern China. These results are important for us to understand N2O emission in natural processes in undisturbed freshwater marsh. Two adjacent plots of Deyeuxia angustifolia freshwater marsh with different water regimes, i.e., seasonally waterlogged (SW) and not- waterlogged (NW), were chosen for
gas sampling, and soil and biomass studies. Emissions of N2O from NW plots were obviously higher than from the SW plots. Daily maximum N2O flux was observed at 13 o′clock and the seasonal maximum occurred in end July to early August. The annual average N2O emissions from the NW marsh were 4.45 μg m−2 h−1 in 2002 and 6.85 μg m−2 h−1 in 2003 during growing season. The SW marsh was overall a sink for N2O with corresponding annual emissions of −1.00 μg m−2 h−1 for 2002 and −0.76 μg m−2 h−1 for 2003. There were significant correlations between N2O fluxes and temperatures of both air and 5-cm-depth soil. The range of soil redox potential 200–400 mV appeared to be optimum
for N2O flux. Besides temperature and plant biomass, the freeze–thaw process is also an important factor for N2O emission burst. Our results show that the freshwater marsh isolated from human activity in northeastern China is not a major
source of N2O. 相似文献
Technological innovation is one of the potential engines to mitigate environmental pollution. However, the implementation of new technologies sometimes fails owing to socioeconomic constraints from different stakeholders. Thus, it is essential to analyze constraints of environmental technologies in order to build a pathway for their implementation. In this study, taking three technologies on rural sewage treatment in Hangzhou, China as a case study, i.e., wastewater treatment plant (WTP), constructed wetland (CW), and biogas system, we analyzed how socioeconomic constraints affect the technological choices. Results showed that socioeconomic constraints play a key role through changing the relative opportunity cost of inputs from government as compared to that of residents to deliver the public good—sewage treatment—under different economic levels. Economic level determines the technological choice, and the preferred sewage treatment technologies change from biogas system to CW and further to WTP along with the increase of economic level. Mismatch of technological choice and economic level results in failures of rural sewage treatment, e.g., the CW only work well in moderately developed regions in Hangzhou. This finding expands the environmental Kuznets law by introducing the coproduction theory into analysis (i.e., inputs from both government and residents are essential for the delivery of public goods and services such as good environmental quality). A match between technology and socioeconomic conditions is essential to the environmental governance.