太湖蓝藻水样中藻蓝蛋白提取方法比较

以2011年8月20日采集的太湖梅梁湾的夏季蓝藻水华为研究对象,通过12个样点平行样的藻蓝蛋白实验提取,基于光谱吸收特征和浓度值,对反复冻融法、超声波法、溶胀法、丙酮法的提取效果进行比较评价.结果表明:4种方法获取的藻蓝蛋白提取液在620 nm附近出现吸收峰,其中,反复冻融法的峰高最强,超声波法最弱,说明反复冻融法的提取效果优于其他方法;反复冻融法、超声波法、溶胀法获取的部分蓝蛋白提取液在670 nm附近具有次吸收峰,与藻蓝蛋白标样的吸收曲线存在差异;反复冻融法、超声波法提取的藻蓝蛋白浓度值变异系数小于0.6,表明这两种方法较其他方法稳定;反复冻融法提取的藻蓝蛋白浓度值高于其他3种方法,可推荐作为太湖蓝藻水样中藻蓝蛋白的提取方法.     

水位、水氡小波分析中期异常提取方法

利用小波分析方法在时间域和频率域都有较高分辨率的特性,建立了水位、水氡的小波中期异常提取的方法.该体系包括研究(预测)目标地震的确定、井(泉)和测项的初选、小波异常的提取及异常性质的鉴定等7个步骤.采用小波异常提取方法,研究了华北、四川及邻区、海南多年积累的震例资料,分析了水位、水氡小波异常与地震活动之间的关系,给出了...     

Rapid Analysis of 1,4‐Dioxane in Groundwater by Frozen Micro‐Extraction with Gas Chromatography/Mass Spectrometry

An innovative micro‐extraction of aqueous samples coupled with gas chromatography/mass spectrometry in selected ion‐monitoring mode (GC/MS‐SIM) was developed to selectively analyze for 1,4‐dioxane with low part‐per‐billion detection sensitivity. Recoveries of 1,4‐dioxane ranged from 93% to 117% for both spiked laboratory reagent water and natural groundwater matrices, the later having elevated organic carbon content (8.34 ± 0.31 mg/L as total organic carbon). We observed that freezing the aqueous sample along with the extraction solvent enhanced the extraction efficiency, minimized physical interferences, and improved sensitivity resulting in a limit of detection for 1,4‐dioxane to approximately 1.6 μg/L. This method substantially reduces the labor, time, reagents and cost, and uses instruments that are commonly found in analytical laboratories. This method requires a relatively small sample volume (200 μL), and can be considered a green analytical method as it minimizes the use of toxic solvents and the associated laboratory wastes.     

时移地震监测天然气水合物开采可行性分析

时移地震储藏监测是一种提高油气采收率的有效技术,但该技术应用需要满足一定的储藏条件,因此时移地震的可行性研究非常有必要.天然气水合物的开采过程,主要是通过有关措施(加温、降压、注入化学材料等)使沉积物中的固态水合物变成气体开采出来,这将改变水合物储层的物理性质和地震反射特性,原理上为进行时移地震监测提供了条件.本文通过数值模拟分析发现:扩散型水合物藏在开采过程中有明显的地震信号变化,可以用时移地震对这类水合物藏的开采进行监测;渗漏型水合物藏的时移地震监测是否可行与其所含气体含量大小有关,气体含量低的可以用时移地震进行检测,气体含量高的是否能用时移地震进行检测要视具体情况而定.     

Application of AMD to the Determination of Crop Protection Agents in Drinking Water. Part IV: Fundamentals of a Confirmatory Test

A method is described for the determination of fifteen active ingredients of plant protecting products in ground-, raw, and drinking water. After extraction and enrichment of the pesticides from the water sample with solid-phase extraction, the extract is fractionated on silica-coated TLC plates, first in a so-called screening gradient by AMD (automated multiple development). The detection of the pesticides is performed by UV multidetection. Positive results from the first separation are confirmed by a second separation on silica in an AMD gradient of distinctly different selectivity, compared to the first separation. Following this strategy, it is possible to distinguish nearly all nonvolatile, from water extractable, active ingredients of plant protecting products in the market. UV spectra are taken for further confirmation of positive results. In most cases, this is possible even at the limit of determination. All chromatograms and spectra shown are raw data, resulting from the confirmatory test DIN 38407 part 11, in the laboratory of one participant*). The method is standardized in the meantime as DIN V 38407-11.     

Examining the Extraction Efficiency of Petroleum-Derived Dissolved Organic Matter in Contaminated Groundwater Plumes

The extraction efficiency of petroleum-derived dissolved organic matter (DOM) was examined for groundwater samples from an aquifer contaminated with crude oil. Five different types of extraction techniques were investigated to determine which method is best suited for the analysis of potentially toxic petroleum-derived DOM. The five types were a liquid-liquid extraction (LLE) with dichloromethane (DCM) and total petroleum hydrocarbons-diesel range (TPH_d) with DCM (EPA method 3510C), and three solid-phase extraction (SPE) stationary phases that are routinely used for extraction of polar analytes from water. For the LLE and TPH_d, that is selective for nonpolar compounds, the extraction efficiency of petroleum-derived DOM decreased downgradient as the petroleum-derived DOM becomes increasingly polar due to biodegradation. In contrast, the average extraction efficiency by the SPE methods was greater than 65% across the gradient. The results showed that SPE is more efficient for extracting petroleum-derived DOM at hydrocarbon-contaminated sites. The use of a method with greater extraction efficiency for partially oxidized hydrocarbons may prove useful in determining relationships between their composition and structure and potential for risks to human health or the environment.     

A comparison of the toluene distillation and vacuum/heat methods for extracting soil water for stable isotopic analysis

Hanford Loam, from Richland, Washington, was used as a test soil to determine the precision, accuracy and nature of two methods to extract soil water for stable isotopic analysis: azeotropic distillation using toluene, and simple heating under vacuum. The soil was oven dried, rehydrated with water of known stable isotopic compositions, and the introduced water was then extracted.

Compared with the introduced water, initial aliquots of evolved water taken during a toluene extraction were as much as 30 ‰ more depleted in D and 2.7 ‰ more depleted in ¹⁸O, whereas final aliquots were as much as 40 ‰ more enriched in D and 14.3 ‰ more enriched in ¹⁸O. Initial aliquots collected during the vacuum/heat extraction were as much as 64 ‰ more depleted in D and 8.4 ‰ more depleted in ¹⁸O than was the introduced water, whereas the final aliquots were as much as 139 ‰ more enriched in D, and 20.8 ‰ more enriched in ¹⁸O. Neither method appears quantitative; however, the difference in stable isotopic composition between the first and last aliquots of water extracted by the toluene method is less than that from the vacuum/heat method. This is attributed to the smaller fractionation factors involved with the higher average temperatures of distillation of the toluene. The average stable isotopic compositions of the extracted water varied from that of the introduced water by up to 1.4 ‰ in δD and 4.2 ‰ in δ¹⁸O with the toluene method, and by 11.0 ‰ in δD and 1.8 ‰ in δ¹⁸O for the vacuum/heat method.

The lack of accuracy of the extraction methods is thought to be due to isotopic fractionation associated with water being weakly bound (not released below 110°C) in the soil. The isotopic effect of this heat-labile water is larger at low water contents (3.6 and 5.2% water by weight) as the water bound in the soil is a commensurately larger fraction of the total. With larger soilwater contents the small volume of water bound with an associated fractionation is not enough to affect the remaining unbound introduced soil water. Pretreatment of the soil to equilibrate the heat-labile water to the test water produced good results for the toluene distillation but not the vacuum/heat extraction method.

Vapors collected over the soils also show stable isotopic variations related to soilwater content. These vapors also appear to be in closer equilibrium with the free water, as extracted by the toluene method, than with the originally introduced water; thus, the soil vapors do not appear to be isotopically affected by the heat-labile water.

The toluene method appears to be better for extracting soil water for stable isotopic analysis because it allows more precise temperature control and excludes the extraction of heat-labile water which is isotopically fractionated. The bound nature of this heat-labile water limits association with the hydrologically active soil water; thus, the exclusion of this water from the soil water attained by toluene distillation may be advantageous. However, the azeotropic nature of toluene distillation affords no benefit and the extraction procedure must continue to completion.     

Bestimmung von polycyclischen aromatischen Kohlenwasserstoffen in Wasser,Sediment, Schlamm und Boden mittels Hochleistungs-Flüssigkeitschromatographie Determination of Polycyclic Aromatic Hydrocarbons in Water,Sludges, Sediments,and Soils by High Performance Liquid Chromatography

The paper describes the state of a standardized method for the determination of polycyclic aromatic hydrocarbons (PAH) in water, sludges, sediments, and soils by high performance liquid chromatography (HPLC). The separation of PAH on different specific PAH-columns is illustrated and the chromatographic conditions in relation to the subsequent programmed fluorescence detection are displayed. A method for the treatment of soil samples using a simple but efficient extraction method by ultrasonication using tetrahydrofuran or acetonitrile as extractants is presented. By means of selected samples, it is demonstrated that the extractive recovery rates of the presented method can compete with those of the conventional soxhlet extraction.     

Analysis of Nitroaromatics and Nitramines in Ammunition Waste Water and in Aqueous Samples from Former Ammunition Plants and Other Military Sites Analyse von Nitroaromaten und Nitraminen in Munitionsabwasser und wäßrigen Proben ehemaliger Munitionsfabriken und anderen Rüstungsaltlasten

Waste water from ammunition production sites and aqueous samples (ground and surface water) on or near former military sites on which explosives were produced or filled, e.g. into shells, may be contaminated by the original explosives—mainly nitrotoluenes (such as dinitrotoluenes, trinitrotoluene (TNT)) and nitramines (such as hexogen (RDX), octogen (HMX), and tetryl) or hexyl, but also by byproducts and compounds formed by biodegradation of the explosives such as aminonitrotoluenes, chlorinated nitrobenzenes and nitrophenols. These compounds can be extracted from aqueous samples by liquid/liquid extraction (using dichloromethane or toluene) or by solid phase extraction using C-18 adsorbents with high recoveries (usually ≥85%) provided they contain only one amino group. Nitrotoluenes, chlorinated nitrobenzenes and aminonitrotoluenes (nitrotoluidines) may be determined by gas chromatography (GC) using selective detectors such as an electron capture detector (ECD), a nitrogen-phosphorus detector (NPD) or a chemiluminescence detector (thermal energy analyzer, TEA). The use of combined gas chromatography/mass spectrometry (GC/MS) under electron impact conditions is even more specific. Detection limits comparable to an ECD or NPD, however, are only achieved if the mass spectrometer is operated under selected ion monitoring (SIM). Nitrophenols are derivatized after extraction by heptafluorobutyric anhydride or by acetic anhydride where the latter method can be directly applied to the aqueous sample. The nitramine explosives, such as RDX, HMX, and tetryl, hexyl, the nitrate esters, such as nitropenta (PETN) and nitroguanidine as well as picric acid cannot, or only with difficulty, be analyzed by gas chromatography. They may be determined by high performance liquid chromatography (HPLC) with UV-detection. The HPLC analysis can be extended to include also nitrotoluenes and nitroaminotoluenes.     

Kurzzeitermittlung der Ablaufqualität von Belebtschlammanlagen anhand der Atmungsaktivität

For checking the quality of the effluent from an activated sludge plant for waste-waters from the sulphite pulp production the respiration of an activated sludge sample in air-saturated water is determined initially without the addition of substrate (ground respiration) and after that with an addition of substrate (methanol, substrate respiration) by means of the Clark-electrode. The measuring device is designed by means of zero displacement in such a way that the difference of the oxygen concentration is indicated by a time relay as the difference quotient. Between the ground respiration and the effluent concentration of BOD₅ exists a significant positive regression, which can be used for controlling the plant. The determination of the substrate respiration serves only for checking with respect to perhaps given inhibition of the conversion of matter by the activated sludge. The determination of the activity of the activated sludge sample takes only 20 min; inclusive of the required determination of the dry matter of sludge, the technique provides a well reproducible measured value for the biochemical conversion in the activated sludge plant within 1… 1.5 h.     

Chemical Control of the Water Hyazinth (Eichhornia crassipes SOLMS) Considering Least Environmental Disturbance

1. In many countries of the tropical and sub-tropical regions, the water hyazinth has become a priority weed problem. The damage effects of the water hyazinth are very versatile and, therefore, control has proved to be absolutely necessary. This control may be realized mechanically, biologically and chemically, with chemical control being the most effective one so far. 2. The basis must be the determination of those quantities and concentrations of the active substances that will enable us to obtain the optimum herbicide efficiency in the control of water hyazinths with the minimum disturbance of the ecosystem. 3. Differences in the herbicide effect in the control of water hyazinths resulted from the different application procedures. There, the best possible effect of control was obtained by means of the spraying procedure having the greatest importance also in practical application. Due to their acute toxicity, the herbicides Gramoxone, Reglone and Azaplant-Kombi proved to be especially favourable. Azaplant had a lower and slower initial effect which could be improved in combination with Sys 67 Omnidel. In order to obtain an optimum phytotoxic effect with the simultaneously least disturbance of the ecosystem, converted 31 Gramoxone, 3 1 Reglone, 25 kg Azaplant-Kombi, 30 kg Azaplant and 20 kg Azaplant in combination with 25 kg Sys 67 Omnidel per hectare water surface proved to be favourable. 4. In the application via the water body, satisfying results could be obtained by means of Azaplant with an optimum concentration of 3.8 ppm and in combination with Sys 67 Omnidel (3.8 ppm + 6.7 ppm Sys 67 Omnidel). Application via the water body should only be realized where the spraying procedure cannot be used. 5. Compared with the necessary herbicide quantities established in literature for the control of aquatic plants, the optimum values determined here are in the range of minimum quantities and they thus result in the least indispensable contamination of the waters.     

Low-Cost Apparatus for On-Site Monitoring of Methane in Ground Water

An upsurge in oil- and gas-well drilling in northwestern Pennsylvania and western New York has been accompanied by several incidents of contamination of ground water by methane. Determining which well is causing the contamination is extremely difficult if more than one gas or oil well is present in the area.
The fact that the solubility of methane decreases as the pressure on ground water decreases provides a quantitative basis for monitoring changes in the amount of methane in the ground water. Quantitative measurements of the volume of methane given off by ground water pumped from a well as the water enters atmospheric pressure permit detection of temporal changes in the gas content which are too subtle to be detected visually. These gas volume changes may, in some cases, be correlated with variations in the pressure of methane in the annulus of nearby individual gas/oil wells and thus may provide a means of pinpointing the gas/oil well that is causing the methane contamination.
The basic principle of the gas-volume monitoring apparatus (GVMA) described in this paper is that as a measured amount of ground water enters atmospheric pressure the gas which comes out of solution is trapped and measured. The GVMA can be constructed of materials costing less than $100 and requires no special skills to assemble or operate. In a recent study conducted in a western New York village, four homeowners were able to collect quantitative gas-volume data from their household water wells daily in about one-half hour. Unlike laboratory analyses for dissolved methane, there is no cost involved in monitoring with the GVMA beyond the initial instrument cost and operator time. Another advantage is that the data are available immediately.     

In Situ Measurement of Electro-Osmotic Fluxes and Conductivity Using Single Wellbore Tracer Tests

Electro-osmosis (EO), the movement of water through porous media in response to an electric field, offers a means for extracting contaminated ground water from fine-grained sediments, such as clays, that are not easily amenable to conventional pump-and-treat approaches. The EO-induced water flux is proportional to the voltage gradient in a manner analogous to the flux dependence on the hydraulic gradient under Darcy's law. The proportionality constant, the soil electro-osmotic conductivity or k_eo, is most easily measured in soil cores using bench-top tests, where flow is one-dimensional and interfering effects attributable to Darcy's law can be directly accounted for. In contrast, quantification of EO fluxes and k_eo in the field under deployment conditions can be difficult because electrodes are placed in ground water wells that may be screened across a heterogeneous mixture of lithologies. As a result, EO-induced water fluxes constitute an approximate radial flow system that is superimposed upon a Darcy flow regime through permeable pathways that may or may not be coupled with hydraulic head differences created by the EO-induced water fluxes. A single well comparative tracer test, which indirectly measures EO fluxes by comparing wellbore tracer dilution rates between background and EO-induced water fluxes, may provide a means for routinely quantifying the efficacy of EO systems in such settings. EO fluxes measured in field tests through this technique at a ground water contamination site were used to estimate a mean k_eo value through a semianalytic line source model of the electric field. The resulting estimate agrees well with values reported in the literature and with values obtained with bench-top tests conducted on a soil core collected in the test area.     

Detection of gas and water using HHT by analyzing P- and S-wave attenuation in tight sandstone gas reservoirs

A direct detection of hydrocarbons is used by connecting increased attenuation of seismic waves with oil and gas fields. This study analyzes the seismic attenuation of P- and S-waves in one tight sandstone gas reservoir and attempts to give the quantitative distinguishing results of gas and water by the characteristics of the seismic attenuation of P- and S-waves. The Hilbert–Huang Transform (HHT) is used to better measure attenuation associated with gas saturation. A formation absorption section is defined to compute the values of attenuation using the common frequency sections obtained by the HHT method. Values of attenuation have been extracted from three seismic sections intersecting three different wells: one gas-saturated well, one fully water-saturated well, and one gas- and water- saturated well. For the seismic data from the Sulige gas field located in northwest Ordos Basin, China, we observed that in the gas-saturated media the S-wave attenuation was very low and much lower than the P-wave attenuation. In the fully water-saturated media the S-wave attenuation was higher than the P-wave attenuation. We suggest that the joint application of P- and S-wave attenuation can improve the direct detection between gas and water in seismic sections. This study is hoped to be useful in seismic exploration as an aid for distinguishing gas and water from gas- and water-bearing formations.     

基于遥感特征指数的地表水体自动提取技术研究

为了从海量遥感数据中有效地提取地表水体信息,并提高自动化提取效率,提出了一种基于遥感特征指数的地表水体自动提取方法.该方法选取归一化植被指数(NDVI)、归一化建筑指数(NDBI)和修正归一化水体指数(MNDWI)作为遥感特征指数集,并根据这些指数构建了遥感特征指数曲线.通过分析,发现地表水体在特征曲线中单调上升,植被在特征曲线中单调下降,而其它地物并无此特征.因此,根据这一规律,利用ERDAS IMAGINE软件建立了自动化提取模型.通过与其他方法对比,表明所建立的模型在精度和自动化方面都明显优于其他方法,可用于海量数据地表水体的自动提取.最后,在ARCGIS环境下,并通过决策树模型初步实现了地表水体的自动分类.     

Zur Bewertung der Analytik und Interpretation des Gruppenparameters “Extrahierbares organisch gebundenes Halogen” von Wässern

Organohalogen compounds are gaining in importance in the control of surface and drinking water due to their unwholesome properties. An accumulation of the organohalogen compounds, occurring mostly at low concentrations, is possible in different ways. The author discusses the possibility and problems of the extractability from waters with the aid of organic solvents. The group parameter EOX that can be determined does not allow any statement concerning components of individual substances, but gives some clues to the state of surface and drinking waters which are mostly anthropogenically polluted. Results of practical examples as well as theoretical considerations indicate the importance of the different distribution coefficients in the solvent/water extraction system. The degree of extraction can be considerably increased by the application of suitable mixtures of solvents. In waters with a known composition, the probably detectable EOX-quantity can be calculated by means of theoretical degrees of extraction.     

CO2 measurements on 1-cm3 ice samples with an IR laserspectrometer (IRLS) combined with a new dry extraction device

A new dry gas extraction and analysis method for small (1 cm³) ice samples is presented. The extraction device, cooled to ?20°C, contains two movable steel needle matrices for crushing the ice. During the crushing process the gas escaping from the ice sample is continuously analyzed for CO₂ with an infrared laserspectrometer. This method enables a fast measurement (few minutes) of the CO₂ concentration in the air bubbles with high spatial resolution in the ice core and a minimum potential contamination. An important CO₂ contamination source due to an interaction of water vapour with surfaces is shortly discussed.The reproducibility of extraction and analysis is ±2%. We analyzed CO₂ concentrations in the trapped air from different ice cores originating from the Greenland ice sheet and from Antarctica.     

石泉井水位异常与九寨沟7.0级地震关联性探讨

选取2014—2020年共计7年的石泉流体井水位整点值数据,结合小波分析方法及区域构造分析,研究石泉井水位长期异常变化的可能原因。结果表明,石泉水位异常活跃主要发生在2017年8月8日九寨沟地震之后,利用小波分析提取高频异常信息效果较好,九寨沟7.0级地震后的区域断裂活动加强或九寨沟地震造成的断裂周边含水层渗透性发生变化可能为导致石泉井水位长期异常的直接原因,未来月河断裂石泉段附近断层活动性值得进一步关注。     

Artefaktfreie GC-Bestimmung von Trihalogenmethanen in Schwimmbeckenwasser nach Anreicherung mittels Headspace-Festphasenmikroextraktion

Artefact-free Determination of Trihalomethanes in Chlorinated Swimming-pool Water Using Headspace Solid-phase Microextraction and Gas Chromatography Headspace solid-phase microextraction (headspace SPME) is a rather new technique for the solvent-free extraction and concentration of volatile substances from water into an organic polymer layer covering a fused-silica fiber. In combination with gas chromatography, the method represents a powerful tool for sensitive headspace investigations. As the adsorption of low boiling substances is favoured at low temperatures, the method can be operated at ambient temperature without formation of artefacts. Therefore, the method is ideally suited for the analysis of volatile disinfection by-products in water including several thermolabile THM-precursors. For the artefact-free determination of trihalomethanes it is superior to headspace gas chromatography under the conditions of the German standard method DIN 38407-F5. Compared to gas chromatography after pentane extraction (DIN 38407-F4), headspace SPME is simpler, less- laborious, better reproducible, and, especially for polar, easily water-soluble components, much more sensitive. In addition, it operates solvent-free and can be automated. Using a 100-μ polydimethylsiloxane-coated fiber, the method is linear over at least 2 orders of magnitude and has a relative standard deviation of 2… 7% in the upper ng/L range. With a 65-μ polydimethylsiloxane/divinylbenzene-coating on the fiber, the sensitivity of the method can be extended to limits of quantitation in the low ng/L range. However, this fiber, shows an increased susceptibility to matrix effects as observed in the presence of diisopentyl ether, which can only be compensated by using the method of standard addition.     

Application of the Response Surface Method for Optimization of Headspace Liquid Phase Microextraction of Trihalomethanes in Drinking Water

An optimized analysis method based on headspace liquid phase microextraction (HS‐LPME) and gas chromatography coupled with mass spectrometry was proposed for the determination of trihalomethanes (THMs) in drinking water. The response surface method (RSM) was used to optimize the extraction of THMs for analysis by HS‐LPME. The temperature, extraction time and NaCl concentration were found to be important extraction parameters. The coefficient of determination (R²) for the model was 94.97%. A high probability value (P < 0.0001) for the regression indicated that the model had a high level of significance. The optimum conditions were seen to be: temperature 42.0°C, NaCl concentration 0.30 g/mL, and extraction time 28 min. The response variable was the summation of the THMs chromatography peak areas and the reproducibility of this was investigated in five replicate experiments under the optimized conditions. The relative standard deviations (RSD%) of the THMs ranged from 8.0–11.6%. The limits of detection (LODs), based on a signal‐to‐noise ratio (S/N) of three ranged from 0.42–0.78 μg/L, and were lower than the maximum limits for THMs in drinking water established by the WHO.