soxhlet extraction with solvent epa 3540
Development and application of liquid phase microextraction techniques in the analysis of environmental pollutants
... sample preparation techniques include sorbent-based and solvent- based microextraction Sorbent-based microextraction is usually termed solid phase microextraction (SPME) Solvent- based microextraction ... liquidphase microextraction techniques One is drop-based solvent microextraction including static liquid-phase microextraction (extraction solvent drop remains static during extraction) and dynamic ... microextraction LPME liquid-phase microextraction LPME/HF liquid-phase microextraction with hollow fiber LLLME liquid-liquid-liquid microextraction LLE liquid-liquid extraction SPE solid-phase extraction...
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Investigation and application of liquid chromatography mass spectrometry in the analysis of polar, less volatile and thermal unstable organic pollutants in environmental and biological samples 6
... Orthogonal array design was employed to optimize both microwave-assisted extraction and supercritical fluid extraction conditions for extracting carbamates (propoxur, propham, methiocarb, ... was employed to optimize the MAE conditions The average recovery of the carbamates was above 94% with good reproducibility under optimum MAE conditions SFE was optimized by a two-level OAD procedure ... from 87% to 98%, except for propham (66%), which probably underwent thermal degradation under the extraction conditions The results indicate that although carbamates tested in this study are thermally...
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Investigation and application of liquid chromatography mass spectrometry in the analysis of polar, less volatile and thermal unstable organic pollutants in environmental and biological samples 5
... 30 ml Extraction Level species settings Goldfish and Tortoises Sea lettuce #: Dummy factor *A: Extraction solvent; B: Extraction temperature; C: Extraction time; D: Volume of extraction solvent; ... the OA (27) matrix for the optimization of MAE from goldfish A B C D Extraction solvent Extraction temperature Extraction time Solvent volume SS 58.3 69.6 1.6 d.f 1 MS 58.3 F-Value Significancea ... OA (27) matrix for the optimization of MAE from tortoises A B C D Extraction solvent Extraction temperature Extraction time Solvent volume SS 67.3 87.1 0.7 d.f 1 MS 67.3 Fa Significance Items...
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Investigation and application of liquid chromatography mass spectrometry in the analysis of polar, less volatile and thermal unstable organic pollutants in environmental and biological samples 4
... fluid extraction procedure g of soil was loaded into the extraction cell CO2, pure or premixed with 10% methanol, was used as the extraction fluid The extraction process started after the extraction ... Experimental design for MASE optimization With MAE, extraction solvents, extraction temperature, time and solvent volume appeared to be the major parameters affecting extraction efficiency In this study, ... used in this optimization are: 1) extraction solvents (factor A); 2) extraction temperature (factor B); 3) extraction time (factor C); 4) volume of extraction solvents 101 (factor D) The level...
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Investigation and application of liquid chromatography mass spectrometry in the analysis of polar, less volatile and thermal unstable organic pollutants in environmental and biological samples 3
... EXPERIMENTAL 3.2.1 Reagents and Sample Preparation A stock solution containing propoxur (1000 µg/ml) was prepared in methanol and diluted with different solvents to obtain working solutions at ... ultrapure water were prepared with the concentrations of 0.025, 0.05, 0.10, 0.25, 0.50 and 1.0 ng/µl, respectively A set of solvent- based (methanol: water, 50:50) standards was also prepared at the same ... Liquid-Liquid Extraction Liquid-liquid extraction with dichloromethane was used for concentrating propoxur and its TPs from the water samples because of the efficiency and simplicity of this extraction...
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Investigation and application of liquid chromatography mass spectrometry in the analysis of polar, less volatile and thermal unstable organic pollutants in environmental and biological samples 2
... compound at 1000 µg /ml were prepared in methanol and diluted with the same solvent to obtain working solutions at various concentrations They were stored at 4°C 45 All solvents used in this study ... standard solutions were prepared in acetone at concentrations of 2.0 mg/ml for each compound and stored at - 4°C Working solutions were prepared by diluting the stock solutions with acetone Polychlorinated ... USA) 7010 injector equipped with a 20-µl loop, a Shimadzu SPD-6AV UVVIS detector and a Shimadzu C-R6A integrator The LC-API-MS analyses were performed with a Thermo Separation gradient HPLC system...
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Investigation and application of liquid chromatography mass spectrometry in the analysis of polar, less volatile and thermal unstable organic pollutants in environmental and biological samples 1
... disadvantages [56,57] Extraction techniques Soxhlet Principles Advantages Disadvantages Sample is placed in an extraction thimble and leached with hot solvent in a Soxhlet extractor for 12-24h Solvent evaporation/concentration ... after extraction In recent years, some novel extraction techniques for solid matrices such as supercritical fluid extraction (SFE), microwave-assisted extraction (MAE) and accelerated -solvent extraction ... sample preparation is necessary prior to chromatography analysis The conventional extraction techniques used for solid matrices are mainly Soxhlet extraction, and sonication Soxhlet extraction...
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Applications of capillary electrophoresis in the analysis of natural products
... CE allows the separation and determination of both ionic and neutral compounds with or without organic solvents The amount of sample required is in the nano-liters range Compared with high performance ... carried toward the cathode with EOF Cations with the highest charge/mass ratios will migrate first, followed by the cations with reduced ratios Next, neutral components migrate with the same velocity ... internal surface These fixed charges can interact with the freely moving charges in the surrounding solvent and result in a movement of the surrounding solvent toward the electrode that has the same...
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Báo cáo khoa học: "PARSING VS. TEXT PROCESSING IN THE ANALYSIS OF DICTIONARY DEFINITIONS" pot
... read a text file and replac~ each word with its tagged counterpart (We are not yet attempting to deal with phrases.) Head finding on noun definitions was done with an awk program which examines consecutive ... the parts of speech The most obvious discrepancy is the slow parsing time for wansifive verbs We are not yet sure why this is, but we suspect it has to with W7"s practice of representing the defined ... magnetic properties to We began with a list of about fifty relations, intending to generate plain parse trees and then examine them for relational triples in a separate step It soon became clear,...
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Báo cáo y học: "Computational challenges in the analysis of ancient DNA" ppsx
... globally with respect to the ancient sequence, not locally as is done using Mega BLAST We therefore implemented a semi-global alignment algorithm that is global with respect to the fragment, local with ... alignment Similarly, reads may fail to produce an alignment with a score high enough to trust Although the average alignment length decreases with increased evolutionary distance, the length of the ... represents spurious similarity embedded within otherwise unrelated sequence or if an indel or other rearrangement has occurred in the evolutionary time separating Neandertals and the compared...
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Báo cáo hóa học: " Some new nonlinear integral inequalities and their applications in the qualitative analysis of differential equations" potx
... , R+ ) be nondecreasing with {h, ω}(x) >0 for x Î (0, ∞) 0 ∞ ds = ∞, with x defined as below Finally, assume that and −1 x0 η(φ (s)) α ∈ C1 (R+ , R+ ) is nondecreasing with a(t) ≤ t If u ∈ C(R+ ... nonnegative constant Moreover, let ω Î C(R+, R+) be nondecreasing with ω(u) >0 on (0, ∞) and a, b, Î C1(R+, R+) be nondecreasing with a(x) ≤ x, b(y) ≤ y on R+ m, n are constants, and m > n >0 If ... R+, R+), i = 1, Let ω Î C(R+, R+) be nondecreasing with ω(u) >0 on (0, ∞) p, q are constants, and p > q >0 If a Î C1(R+, R+) is nondecreasing with a (t) ≤ t on R+, and α(t) xp (t) ≤ a(t) + + h1...
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A discourse analysis of presuppositions in the declaration of independence made by president ho chi minh = phân tích diễn ngôn các tiền giả định trong tuyên ngôn độc lập của chủ tịch hồ chí minh
... largely in relation to other groups For example, oppressed with respect to dominators, anti-racists with respect to racists or feminists with respect to chauvinist men… we may expect a special focus ... Moscow with David tomorrow At home, take care of yourself! Wife: Don’t worry! Everything will be okay,…except that I will miss you a lot Husband: Uhm, I’ll phone you regularly 10 Wife: OK, I’ve prepared ... analysis attempts to relate structures of discourse with structures of society For example, social relations of class, gender, or ethnicity are associated with the structural units, levels or strategies...
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An analysis of errors made by high school student in the use of subject verb agreement in english writing = phân tích lỗi sai của học sinh PTTH về sự tương hợp giữa chủ ngữ và động từ trong văn viết tiếng anh
... pub) 15 + When the subject consists of two elements joined by "with' , "together with" , "as well as", "accompanied by", " along with" , "in addition", "including", the form of the verb depends ... agreement of the verb with whatever noun or pronoun closely precedes it, somtimes in preference to agreement with the headword of the subject" (Quirk et al, 1972:360) (1) Concord of verb with disjunctive ... percentages With fractions and percentages, verb agreement depends on the nouns or clauses after them - With singular nouns, clausal subjects or non- count subjects, the singular verb is taken, and with...
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The analysis of theme and rheme in little house on the prairie = sự phân tích về đề ngữ và thuyết ngữ, thông qua truyện ngôi nhà nhỏ trên thảo nguyên
... textual function Within the textual function, the clause operates as a message, which constitutes a text (a discourse), in the relationship with others that are related to it within a discourse ... that, provide English users with an insight into ThemeRheme for their studying and using - To study the utilities of Theme- Rheme in the book "Little House on the Praire" with certain and notable ... Strictly, we have tried to present an overview of Theme and Rheme with all fields related However, due to the time constraints and within the framework of a graduation thesis, we would like to analyze...
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Tài liệu Báo cáo khoa học: A systems biology approach for the analysis of carbohydrate dynamics during acclimation to low temperature in Arabidopsis thaliana doc
... parameters and to validate them with experimental data, 50 independent identification processes with varying initial carbohydrate levels were performed, yielding means with corresponding SDs of estimated ... correlated neither with photosynthesis nor with the cold acclimation process This may explain why we, using C24 and Rsch, did not find a negative correlation of freezing tolerance with channelling ... DX-500 gradient chromatography system coupled with a pulsed amperometric detection by a gold electrode For starch extraction, pellets for ethanol extraction were solubilized by heating them to...
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Tài liệu A REVIEW OF INDOOR AIR POLLUTION AND HEALTH PROBLEMS FROM THE VIEWPOINT OF ENVIRONMENTAL HYGIENE: FOCUSING ON THE STUDIES OF INDOOR AIR ENVIRONMENT IN JAPAN COMPARED TO THOSE OF FOREIGN COUNTRIES pptx
... of room.77) Toluene is an organic solvent with a typical smell of paint thinners and its chemical formula C7 H8 It is widely used as raw material and as a solvent, and is the common name for ... used as a solvent and in printing ink.80) Para-dichlorobenzene, 1,4-dichlorobenzene, is an organic compound with the chemical formula C6 H4 Cl2 , forms colorless to white crystals with a characteristic ... n-Tetradecane is an alkane with the chemical formula C14 H30 ,95) is found in vinyl flooring together with n-pentadecane and phenol.96) DEHP is an organic compound with the chemical formula C24...
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Tài liệu Aesthetic preferences and the attribution of meaning: Environmental categorization processes in the evaluation of urban scenes ppt
... (housing area) with a high crime rate The remaining places were mentioned by less than 10% of participants, with 31 places being cited on just one occasion Figure shows the frequency with which people ... 01) with restorative capacity: harmony, openness, luminosity, suitability for leisure, and meeting place Of these, the last two, along with openness, also present significant correlations with ... present a significant correlation with the total scale or with any of the factors Neither does the level of upkeep/maintenance, a variable closely associated with a preference for urban spaces,...
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Tài liệu STRATEGIC ENVIRONMENTAL ASSESSMENT on shrimp farms in the southeast of Thailand docx
... compared with each other with reference to the different impacts The main environmental impacts are due to chemical use, mangrove destruction, salinisation, eutrophication, sedimentation, extraction ... project directors and consultants 1.2 Methodology The study includes interviews with shrimp farmers and with expertise at Departments, University institutions and Environmental organisations Employees ... with the saline soil With access to freshwater and the potential for very high profits relative to rice production, a large number of farmers convert paddy fields into shrimp ponds A farmer with...
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The analysis of AHAs in cosmetic
... prepared as the internal standard stock solution 2,000 µg/mL of Glycolic acid, dl-Malic acid, Lactic acid and Citric acid was prepared as the standard stock solution Standard solutions were prepared ... weighed precisely, mixed with an appropriate amount of the internal standard stock solution, dissolved with water, and sonificated for 30 minutes Sonicated samples were diluted with water to the final ... shown in Figure Four AHAs are all acidic compounds with short retention time when using polar solvent as mobile phase and therefore, could not be separated completely We tested the concentration...
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