加速溶剂萃取和净化-气相色谱-串联质谱法测定典型污染场地土壤中多氯联苯残留

建立了加速溶剂萃取同步净化-气相色谱-三重四极杆串联质谱法测定污染场地土壤中7种指示性多氯联苯的方法。对加速溶剂萃取、净化、色谱柱、串联质谱离子对、碰撞电压等条件进行了优化。萃取和净化过程合二为一,串联质谱法提高了7种多氯联苯的灵敏度。7种多氯联苯在0.1～100μg/L质量浓度范围内线性良好,线性相关系数为0.999 80～0.999 99,方法检出限为0.004～0.010μg/kg,回收率为84.8%～97.3%,相对标准偏差为2.4%～8.5%。运用网格法采集了华东某典型污染场地土壤中31个土壤样品,分析了该场地7种指示性多氯联苯的残留特征。7种多氯联苯的检出率为100%,检出范围为0.096～3 661μg/kg,各点平均值为307μg/kg。各采样点中多氯联苯的残留程度存在很大差异,局部点位受到了较重污染,与封存点相近的部分点位残留较外围位置高。土壤中多氯联苯同系物以三氯联苯、四氯联苯、五氯联苯为主,占同系物总量的98.2%。该污染场地土壤多氯联苯主要是低氯代联苯污染,土壤中多氯联苯的毒性效应评估处于中等水平,污染以点源污染为主,且已有较大程度扩散。     

分散液液微萃取-气相色谱/质谱联用法测定饮用水源水中的四乙基铅

采用分散液液微萃取与气相色谱/质谱法联用技术建立了测定水样中四乙基铅的方法。考察了影响分散液液微萃取的因素,包括萃取溶剂、分散剂、萃取次数、萃取时间和盐效应等。在最佳条件下,四乙基铅的富集倍数为330倍,检出限为0.01μg/L(S/N=3),线性范围为0.10~10.0μg/L,线性相关系数为0. 9992。测定饮用水源水中的四乙基铅,加标回收率为87.7%~105%,相对标准偏差为4.8%~7.3%(n=3)。     

搅拌棒萃取-热脱附/气质联用法测定水中2-MIB和土臭素

采用搅拌棒萃取-热脱附/气质联用法测定水中2-甲基异莰醇和土臭素,优化了搅拌棒萃取和热脱附进样的条件。试验表明：两种目标化合物在1．00 ng/L～200 ng/L范围内线性良好,2-甲基异莰醇的相关系数为0．9993,土臭素的相关系数为0．9997,方法检出限分别为0．31 ng/L和0．15 ng/L;空白和实际样品的加标回收率为82．4％～116％,测定结果的RSD＜10％。     

水浴消解-原子荧光法测定土壤中的砷汞

建立了王水水浴消解-原子荧光法测定土壤中砷汞的方法,确定还原剂为硼氢化钾,测砷和汞时硼氢化钾的最优质量分数分别为2%和0.05%,载流为5%盐酸。该法砷和汞分别在质量浓度0.0~40.0μg/L和0.00~4.00μg/L范围内线性良好,相关系数均0.999 5,砷和汞的检出限分别为0.009和0.001 mg/kg,相对标准偏差分别为3.90%和2.67%,加标回收率分别为94.1%~107.6%和92.0%~104.0%。采用本法对国家标准土壤样品和东海县部分农田土壤样品进行测定分析,结果良好,表明该法操作简单、灵敏度高、实用性好,适用于土壤中砷和汞的测定。     

UPLC-MS/MS法同时测定地表水中多种有机污染物

采用超高效液相色谱-串联质谱法直接进样测定地表水中26种有机污染物,通过优化试验条件,使各目标化合物在1.00μg/L^100μg/L范围内线性良好,相关系数(r 2)>0.995,方法检出限为0.003μg/L^1.0μg/L。将该方法用于地表水样的测定,加标回收率为79.0%~120%,6次测定结果的RSD均<15%。     

Decomposition of Al13 promoted by salicylic acid under acidic condition: Mechanism study by differential mass spectrometry method and DFT calculation

Decomposition of the polycation Al₁₃O₄(OH)₂₄(H₂O)₁₂⁷⁺ (Al₁₃) promoted by ligand is a vital subject to advance our understanding of natural and artificial occurrence and evolution of aluminum ions, especially in the case of acidic condition that dissolved Al³⁺ species can be released from the Al-bearing substances. However, the microscopic pathway of synchronous proton-promoted and ligand-promoted decomposition process for Al₁₃ is still in the status of ambiguity. Herein, we applied differential mass spectrometry method and DFT calculation to study the initial detailed process of Al₁₃ decomposition under the presence of proton and salicylic acid (H₂Sal). Mass results showed that the mononuclear Al³⁺-H₂Sal complexes dominated the resulting Al species, whereas the monodentate complex Al₁₃HSal⁶⁺ was not observed in the spectra. The difference of decomposition levels between the ligand/Al ratio 0.2 and 0.5 cases revealed that proton and ligand performed synergistic effect in initial Al₁₃ decomposition process, and the proton transfer determined the ring closure efficiency. The ring closure reaction is the prerequisite for the collapse of Al₁₃ structure and detachment of the mononuclear complex. DFT calculations reveal that hydrogen bond plays an important role in inducing the formation of chelated complex accompanying proton transfer. Attachment of protons at the bridging OH⁻ can elongate and weaken the critical bond between targeted Al³⁺ and µ₄-O^2- resulting from delocalization of electron pairs in the oxygen atom. These results demonstrate the detailed mechanism of Al₁₃ composition promoted by ligand and proton, and provide significant understanding for further application and control of Al₁₃.     

Syntrophic co-culture of Bacillus subtilis and Klebsiella pneumonia for degradation of kraft lignin discharged from rayon grade pulp industry

In order to search the degradability of kraft lignin, the potential bacterial strains Bacillus subtilis (GU193980) and Klebsiella pneumoniae (GU193981) were isolated, screened and applied in axenic and co-culture conditions. Results revealed that mixed culture showed better decolorization efficiency (80%) and reduction of pollution parameters (COD 73% and BOD 62%) than axenic culture. This indicated syntrophic growth of these two bacteria rather than any antagonistic effect. The HPLC analysis of degraded samples of kraft lignin has shown the reduction in peak area compared to control, suggesting that decrease in color intensity might be largely attributed to the degradation of lignin by isolated bacteria. Further, the GC–MS analysis showed that most of the compounds detected in control were diminished after bacterial treatment. Further, the seed germination test using Phaseolus aureus has supported the detoxification of bacterial decolorized kraft lignin for environmental safety. All these observations have revealed that the developed bacterial co-culture was capable for the effective degradation and decolorization of lignin containing rayon grade pulp mill wastewater for environmental safety.     

The potential leaching and mobilization of trace elements from FGD-gypsum of a coal-fired power plant under water re-circulation conditions

Experimental and geochemical modelling studies were carried out to identify mineral and solid phases containing major, minor, and trace elements and the mechanism of the retention of these elements in Flue Gas Desulphurisation (FGD)-gypsum samples from a coal-fired power plant under filtered water recirculation to the scrubber and forced oxidation conditions. The role of the pH and related environmental factors on the mobility of Li, Ni, Zn, As, Se, Mo, and U from FGD-gypsums for a comprehensive assessment of element leaching behaviour were also carried out. Results show that the extraction rate of the studied elements generally increases with decreasing the pH value of the FGD-gypsum leachates. The increase of the mobility of elements such as U, Se, and As in the FGD-gypsum entails the modification of their aqueous speciation in the leachates; UO₂SO₄, H₂Se, and HAsO₂ are the aqueous complexes with the highest activities under acidic conditions. The speciation of Zn, Li, and Ni is not affected in spite of pH changes; these elements occur as free cations and associated to SO₄² in the FGD-gypsum leachates. The mobility of Cu and Mo decreases by decreasing the pH of the FGD-gypsum leachates, which might be associated to the precipitation of CuSe₂ and MoSe₂, respectively. Time-of-Flight mass spectrometry of the solid phase combined with geochemical modelling of the aqueous phase has proved useful in understanding the mobility and geochemical behaviour of elements and their partitioning into FGD-gypsum samples.     

The potential leaching and mobilization of trace elements from FGD-gypsum of a coal-fired power plant under water re-circulation conditions

Experimental and geochemical modelling studies were carried out to identify mineral and solid phases containing major, minor, and trace elements and the mechanism of the retention of these elements in Flue Gas Desulphurisation (FGD)-gypsum samples from a coal-fired power plant under filtered water recirculation to the scrubber and forced oxidation conditions. The role of the pH and related environmental factors on the mobility of Li, Ni, Zn, As, Se, Mo, and U from FGD-gypsums for a comprehensive assessment of element leaching behaviour were also carried out. Results show that the extraction rate of the studied elements generally increases with decreasing the pH value of the FGD-gypsum leachates. The increase of the mobility of elements such as U, Se, and As in the FGD-gypsum entails the modification of their aqueous speciation in the leachates; UO₂SO₄, H₂Se, and HAsO₂ are the aqueous complexes with the highest activities under acidic conditions. The speciation of Zn, Li, and Ni is not affected in spite of pH changes; these elements occur as free cations and associated to SO₄ ² in the FGD-gypsum leachates. The mobility of Cu and Mo decreases by decreasing the pH of the FGD-gypsum leachates, which might be associated to the precipitation of CuSe₂ and MoSe₂, respectively. Time-of-Flight mass spectrometry of the solid phase combined with geochemical modelling of the aqueous phase has proved useful in understanding the mobility and geochemical behaviour of elements and their partitioning into FGD-gypsum samples.     

原子荧光光谱法测定环境水体中痕量锡研究

在对环境水进行检测时,一个非常重要的项目就是对锡含量进行检测,所以,运用准确、灵敏的测定方法对环境水体中痕量锡进行检测具有非常重要的意义。文章将结合实验,在对环境水体中的痕量锡进行测定时,运用原子荧光光谱法,对测定环境水体中痕量锡的方法进行了一定的研究。采用原子荧光光谱法测定环境水体中的痕量锡,方法检出限是0.10μg/L,相对标准偏差0.20%~0.90%,实际样品加标回收率为98%~102%,满足环境监测实验室分析测定要求,值得推广。