杭州市冬季大气气溶胶PM2.5中二恶英和多氯联苯的污染特征

2014年1月在杭州市选择5个点位采集大气颗粒物PM_2.5样品,采用同位素稀释高分辨气相色谱/高分辨质谱测定PM_2.5中的二恶英（PCDD/Fs）和多氯联苯（PCBs）,对PM_2.5的污染状况以及PM_2.5中PCDD/Fs和PCBs的污染水平及分布特征进行了研究。PM_2.5的质量浓度范围为85~168 μg/m³,PM_2.5污染较重,但与2004年同期相比明显降低。PM_2.5中PCDD/Fs的毒性当量（TEQ）为0.277~0.488 pg I-TEQ/m³,明显高于2004年同期采集样品。颗粒物中PCDD/Fs以八氯代二苯并-对-二恶英（OCDD）为主,毒性当量主要贡献者为2,3,4,7,8-五氯代二苯并呋喃（2,3,4,7,8-PeCDF）。PM_2.5中PCBs的质量浓度范围为2.9~8.1 pg/m³,二恶英类多氯联苯（DL-PCBs）的毒性当量范围为2.6~6.1 fg WHO-TEQ/m³,污染较低。PCBs在颗粒物中分布以PCB-28为主,但对毒性当量贡献最大的为PCB-126。PCDD/Fs和PCBs的气-固分配特征表现为PCDD/Fs主要分布于颗粒物中,而PCBs主要分布于气相中。     

同位素稀释高分辨气相色谱-高分辨质谱法测定土壤样品中二恶英类化合物的等价毒性当量不确定度的评定

采用同位素稀释高分辨气相色谱-高分辨质谱法（isotope dilution high resolution gas chromatography and high resolution mass spectrometry,ID-HRGC-HRMS）测定土壤样品中二恶英类化合物（polychlorinated dibenzo-p-dioxins and dibenzofurans,PCDD/Fs）的等价毒性当量（toxic equivalent quantity,TEQ）。讨论并确定了测定土壤样品中二恶英类化合物2,3,7,8位异构体不确定度的来源并合成了各异构体的相对标准不确定度;在此基础上,计算了3种等价毒性当量因子（toxic equivalent factor,TEF）框架下土壤样品中PCDD/Fs的TEQ浓度及其合成不确定度和扩展不确定度。     

Rapid and cost-effective analysis of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in soil, fly ash and sediment certified reference materials using pressurized liquid extraction with an integrated carbon trap

Pressurized liquid extraction with an integrated carbon trap (PLE-C) has recently been developed for fast and efficient analysis of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in food and feed. The method has also been tested, but not verified, for use on more complex soil samples, such as soil, sediment and fly ash. Hence, the primary aim of this study was to verify that PLE-C can produce reliable data for PCDDs/PCDFs in various abiotic matrixes. A second aim was to find a replacement for the previously used AX21 active carbon that is currently not commercially available. The performance of the PLE-C was evaluated using both single congener concentrations and toxic equivalency potentials (TEQ-pot) of three (soil, sediment and fly ash) certified reference materials. The results clearly show that PLE-C can be used for abiotic samples and that a commercially available carbon (Norit SA 4PAH HF) can replace the AX-21 carbon in the carbon trap. The TEQ-pot values obtained for the soil and sediment samples were within the uncertainty limits of the corresponding certified values, as were the determinations of single congener concentrations. PLE-C therefore has great potential for determination of PCDDs/PCDFs in soil and sediment samples. The TEQ-pot result for the fly ash was slightly lower than the certified TEQ-pot value, but it is still within the uncertainty limits of the certified value. Out of the single congener concentrations all but four (out of 17) agreed well with the values. Hence, PLE-C may potentially be used also for fly ash—after slight modifications. The integrated PLE-C and cleanup procedure is less labour-intensive than traditional methods such as Soxhlet extraction followed by a multistep cleanup, and consumes smaller quantities of ultrapure solvents than the commonly used Power-Prep system. In addition, PLE-C is capable of larger sample throughputs than the conventional methods. Thus, PLE-C is a promising alternative to the currently used sample preparation procedures for dioxins in abiotic samples. Figure PLE with integraded carbon trap for rapid PCDD/Fs analysis Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Determination of pharmaceuticals from various therapeutic classes in dewatered sludge by pressurized liquid extraction and high performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS)

Pharmaceuticals are released to the environment after human and animal consumption, which partly comes from accumulation in sewage sludge during wastewater treatment. This paper developed a method for the determination of N,N-diethyl-meta-toluamide (DEET) and 14 pharmaceuticals belonging to multiple therapeutic classes such as antibiotic, anti-inflammatory, antilipidemic, anti-hypertensive, and anticonvulsant in dewatered sludge. Pressurized liquid extraction using methanol/McIlvaine buffer (volume ratio, 1?:?1), associated with HPLC-MS/MS was proven to be effective for extraction and quantification of pharmaceuticals and DEET in dewatered sludge. Optimization procedures, including extraction method, extraction solvents and clean-up treatment, were carried out by simulating naturally aged samples to provide a more realistic extraction than previous methods, which were often done by spiking the standard solution before extraction without any aging procedures. The internal standard quantification method using six isotopically labelled compounds was applied to improve the poor absolute recoveries induced by severe matrix effects to obtain better relative recoveries (70–120%). Good relative standard deviations (lower than 19.0% for 7 repeats) and the limit of quantification (0.6–19.4?µg/kg) indicated that the developed method was reliable and sensitive to extract and quantify the studied pharmaceuticals in dewatered sludge. For samples collected from eight sewage treatment plants in Beijing, China, it was found that trimethoprim, caffeine, ketoprofen and ibuprofen were the most prominent contaminants, with the median concentrations reaching 97.6, 179.4, 268.0 and 153.0?µg/kg, respectively. The level of ketoprofen, ibuprofen, mefenamic acid, cabamazepine and diclofenac were similar to results reported from Spain, whilst the levels of other compounds were similar to those found in Germany, Canada and the US.     

Trace enrichment and HPLC analysis of polycyclic aromatic hydrocarbons in environmental samples,using solid phase extraction in connection with UV/VIS diode-array and fluorescence detection

Summary Both the separation of polycyclic aromatic hydrocarbons (PAH's) on tailor made HPLC phases, and their chromatographic enrichment and quantitative determination are of great interest. Because of the generally low concentrations of PAH's in the environment, and the low limiting values in German legislation for drinking water, methods for selective enrichment and sensitive detection are indispensable. On account of their relatively high amounts in soil, the determination of PAH's is valuable for the assessment of the potential danger to ground water by waste materials. These requirements can be fulfilled by used of solid phase extraction on enrichment columns, and fluorescence or UV/VIS diode array detection. For the detection of PAH's in the picogram range, the wavelengths for excitation and emission were time programmed over the chromatogram. With this feature, it is possible to detect all the individual compounds at the highest sensitivity, over the entire analysis.     

Qualitative and quantitative determination of nucleosides, bases and their analogues in natural and cultured Cordyceps by pressurized liquid extraction and high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS)

A simple and rapid pressurized liquid extraction (PLE) and high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) method was developed for qualitative and quantitative determination of nucleosides, bases and their analogues in natural and cultured Cordyceps. The samples were extracted using PLE. The separation was achieved on a ZORBAX Eclipse XDB-C₁₈ column with gradient elution of methanol and 5 mM aqueous ammonium acetate as mobile phase. Target compounds were identified by characterizing their product ions, precursor ions and retention times. Quantitative analysis of investigated compounds were performed using time programmed selective ion monitoring (SIM) or selective reaction monitoring (SRM) with 10 segments in positive (negative for uridine) ion mode. The results showed that 43 bases, nucleosides and their analogues were detected in Cordyceps, of these 16 compounds were identified. The simultaneous determination of seven nucleosides and six bases in Cordyceps was achieved using PLE and HPLC-ESI-MS/MS method described above, which afforded good linearity, selectivity, precision, recovery, short analysis time as well as LOD and LOQ in the ng/ml range.     

Sensitive determination of strongly polar aromatic amines in water samples by stir bar sorptive extraction based on poly(vinylimidazole-divinylbenzene) monolithic material and liquid chromatographic analysis

A simple and sensitive method for the determination of polar aromatic amines (PAAs) was developed using stir bar sorptive extraction (SBSE) coupling to high-performance liquid chromatography. A hydrophilic poly(vinylimidazole-divinylbenzene) (VIDB) monolithic material was prepared and acted as SBSE coating. The influences of polymerization conditions for VIDB on the extraction efficiency were investigated using aniline and 2,4-dinitroaniline as detected solutes. To achieve optimum extraction performance for PAAs, several parameters including extraction and desorption time, desorption solvent, ionic strength and pH value of sample matrix were investigated. The results showed that under the optimized experimental conditions, the method showed good sensitivity and excellent recoveries, as well as advantages such as linearity, simplicity, low cost and high feasibility. The extraction performance of present method to the target compounds also compared with commercial SBSE which using polydimethylsiloxane as coating and other SBSE which based on monolithic materials. Finally, the proposed method was successfully applied to the determination of PAAs in lake and sea waters, and excellent recoveries of spiked target compounds in real samples were obtained.