高效液相色谱法测定土壤中多环芳烃的条件优化

研究了加速溶剂萃取(ASE)、固相萃取柱净化(SPE)、高效液相色谱仪(HPLC)联合测定土壤中16种多环芳烃(PAHs)的分析方法,选择以正己烷/丙酮(1+1,V/V)作为ASE提取溶剂,提取液经SPE硅胶小柱净化,正己烷/二氯甲烷(1+1,V/V)进行洗脱,洗脱体积为10 m L,洗脱液经旋转蒸发浓缩至近干,过0.22μm有机滤膜,用乙腈定容至1 m L,最后用HPLC-紫外检测器对提取液中16种PAHs进行定量分析。土壤中16种PAHs的方法检出限为2.8~4.9μg/kg,加标回收率为81.9%~102%,相对标准偏差为2.5%~6.2%,完全满足土壤中PAHs分析的质量控制要求,该法稳定性好、准确度高、可操作性强,适合于土壤样品中16种PAHs的准确测定。     

水和废水中甲乙酮监测分析方法研究

研究了水和废水中甲乙酮经气提 (吹扫 )在常温下用 2 ,4 -硝基苯肼 (DNPH)酸性饱和溶液吸收 ,经衍生形成甲乙酮腙 ,用CS2 萃取后再用气相色谱 (GC -FID)以OV - 175 % /ShimaliteW为固定相和载体 ,分离测定的方法 ,对水和废水中的甲乙酮的测定获得满意的结果     

Monitoring of Pesticide Residues in Fruits

Fruit samples of ber, grapes and guava analysed for pesticide residues employing multiresidue analysis by gas liquid chromatography equipped with ECD and NPD detectors and capillary columns showed contamination with organochlorine, synthetic pyrethroid and organophosphate insecticides. Among organochlorines, HCH, DDT and endosulfan were detected in almost all the samples. Residues of HCH and DDT were maximum in ber followed by grapes and guava where as of endosulfan were maximum in guava followed by grapes and ber. All the fruit samples showed the presence of residues with one or the other group of pesticides. Residues of none of the pesticides exceeded the MRL values in any sample. On the basis of these studies, it is suggested that monitoring studies should be extended to other fruits grown in different agro climatic regions which may serve as basis for future policy in chemical use.     

天然气管道工程风险对策研究

风险管理对策包括风险规避、风险控制与消减、风险自留和风险转移四个方面,风险管理的目标即是通过科学的风险管理策略使风险降到可以接受的水平。企业对风险的容忍程度除与风险控制的期望成本相关外,还与企业的风险偏好,以及政治、经济等外部环境因素相关。管道建设工程面临的风险因素复杂,可以从人的因素、物的因素、环境的因素和管理的因素四个方面进行识别和归类。各风险事件发生的町能性以及后果严重性各不相同,在管道建设工程风险管理中过程中要综合采用各种风险对策,使每一风险因素降低到企业所能够承受的水平,甚至可以采用改线绕过特定风险地域或保险转移的策略,使项日业主不再承担特定的风险责任。     

Microwave-assisted stripping of oil contaminated drill cuttings

The application of microwave heating technology to conventional gas stripping processes has been investigated in the remediation of contaminated drill cuttings. The technical feasibility and limitations of nitrogen and steam stripping processes are demonstrated, and it is shown that the combination of microwave heating with the stripping process offers a step change in performance. Order of magnitude improvements in processing time are shown for the microwave-assisted processes, as well as greatly improved levels of remediation. The mechanisms of contaminant removal are discussed, along with the phenomena which occur with microwave heating processes. The energy requirements of each of pure gas and microwave-assisted processes are also discussed, and the potential applications of each technology are highlighted relative to the overall remediation requirements.     

Crosslinking and stabilization of high fractional free volume polymers for gas separation

Crosslinkable poly(4-methyl-2-pentyne) (PMP) membranes were cast from carbon tetrachloride solutions containing PMP and either 4,4′-diazidobenzophenone or 4,4′-(hexafluoroisopropylidene)diphenyl azide. The composite membranes were transparent and homogeneous and were crosslinked by UV irradiation at room temperature or thermal treatment at 180 °C. Low levels of the bis(aryl azide) (1–4.5 wt%) were effective in rendering the membranes insoluble in cyclohexane and carbon tetrachloride, both are good solvents for PMP, thus PMP can easily be converted to mechanically stable membranes with permeabilities and selectivities comparable or higher than those of the well-known poly(dimethylsiloxane) (PDMS). The permeabilities of O₂, N₂, H₂, CH₄ and CO₂ were measured. Compared to pure PMP, the crosslinked membranes containing bis(aryl azide) had lower permeabilities and higher selectivities, consistent with a reduction in free volume.     

Analysis of a gas-phase partitioning tracer test conducted in an unsaturated fractured-clay formation

The gas-phase partitioning tracer method was used to estimate non-aqueous phase liquid (NAPL), water, and air saturations in the vadose zone at a chlorinated-solvent contaminated field site in Tucson, AZ. The tracer test was conducted in a fractured-clay system that is the confining layer for the underlying regional aquifer. Three suites of three tracers were injected into wells located 14, 24, and 24 m from a single, central extraction well. The tracers comprised noble gases (traditionally thought to be nonsorbing), alkanes (primarily water partitioning), perfluorides (primarily NAPL partitioning), and halons (both NAPL and water partitioning). Observations of vacuum response were consistent with flow in a fractured system. The halon tracers exhibited the greatest amount of retardation, and helium and the perfluoride tracers the least. The alkane tracers were unexpectedly more retarded than the perfluoride tracers, indicating low NAPL saturations and high water saturations. An NAPL saturation of 0.01, water saturation of 0.215, and gas saturation of 0.775 was estimated based on analysis of the suite of tracers comprising helium, perfluoromethylcyclohexane and dibromodifluoromethane, which was considered to be the most robust set. The estimated saturations compare reasonably well to independently determined values.     

Environmental sustainability and the integration of different methods for its assessment

The aim of this paper is to propose a research framework, based on the joint use of three widely used methods: EMergy Evaluation (EME), Ecological Footprint Analysis (EFA) and Greenhouse Gas Inventory (GHGI), that are applied to assess the environmental sustainability of a region. The results of application of these methods to several Italian Provinces enabled us to compare their sustainability, and to test the methods with respect to sustainability requirements at local and global level. The outcomes suggest that the proposed framework provides an organic evaluation of regional systems based on key aspects, such as resources depletion, consumption patterns, waste production and absorption.     

Determination of dithiocarbamate fungicide propineb and its main metabolite propylenethiourea in airborne samples

A simple, rapid and sensitive GC–MS method for the determination of dithiocarbamate fungicide propineb [polymeric zinc propylenebis (dithiocarbamate)] and an improved HPLC procedure for the simultaneous determination of its main metabolite, propylenethiourea, and ethylenethiourea, the main metabolite of all ethylenedithiocarbamates, in airborne samples are described. The method for the analysis of propineb involves the evolution of carbon disulfide (CS₂), under acidic conditions in the presence of stannous chloride, extraction of the generated CS₂ into a layer of isooctane which is then analyzed for CS₂ content by GC–MS in SIM mode. Under the optimum conditions, the retention time of CS₂ was 1.89 min and the total time of chromatographic analysis was 5 min. Recoveries from spiking glass microfibre filters (GF/A) and silica gel filters were 86 ± 7 (n = 9) and 89 ± 4 (n = 9), respectively. The limit of detection is 0.7 ng per filter, which is equivalent to about 0.8–1.0 ng m⁻³ in air. In parallel, an HPLC method with ultraviolet detection is presented for the simultaneous analysis of the metabolites. Separation of the two metabolites was attained in less than 5 min. Recoveries from spiking GF/A and silica gel filters for ethylenethiourea were 100 ± 1 (n = 3) and 98 ± 2 (n = 3), respectively, while for propylenethiourea were 102 ± 1 (n = 3) and 98 ± 1 (n = 3), respectively. The detection limits are about 36–43 and 40–49 ng m⁻³ in air for ethylenethiourea and propylenethiourea, respectively. All the analytes spiked in the filters are proven to be stable for more than one month, at −4 °C.     

气相色谱-质谱法测定土壤中的汽油及其组分含量

对土壤中的汽油,采用外标法,经吹扫捕吸仪浓缩后,用气相色谱-质谱法分析定量。同时,用峰面积归一化法,可以测定土壤中汽油的组分含量。