• Journal of Korean Society for Atmospheric Environment
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• v.14 no.E
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• pp.27-40
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• 1998

The solubility characteristics of organic compounds were studied in terms of the extraction efficiency as a function of the polarity of the organic solvent, and the acidity of water in urban aerosol samples collected in University of East Anglia (UEA), Norwich, England. The extraction efficiency of organic compounds were evaluated with respect to the organic carbon, -nitrogen and -hydrogen by means of a wide range of solvent which include polar and nonpolar organic solvents as well as acids and alkaline water. In addition, after being dissolved in aqueous solution, the aqueous chemistry of organic compounds were studied in terms of the organic metal complexes in aerosol, which were studied with oxalic acid, copper, and zinc. The results of this study indicate that solubility characteristics of organic compounds depend on the polarity of the solvents and the acidity of the solvents. In particular, some organic compounds are water soluble, even though they are much smaller than acetone soluble fractions. In the comparison between polar organic solvent extraction and non- polar organic solvent extraction, it can be thought that significant fraction of organic compounds analysed in the aerosol samples, are polar organic compounds because of the higher extraction efficiencies of organic compounds in polar organic solvent extraction than in nonpolar organic solvent extraction. Regarding the study of the oxalic -metal complexes, it can be thought that most oxalic acids are present in the form of oxalic -copper complexes in the aerosols collected at UEA.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.2
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• pp.209-221
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• 1996

The purpose of this study was to find a suitable cosolvent to $CS_2$ so that desorption efficiency can be improved for both polar and non-polar organic solvent mixtures collected on an activated charcoal tube. Cosolvents added to $CS_2$ include: DMF(N,N-dimethylformamide): $CS_2$ (v/v 1:99), DMF:$CS_2$(v/v 3:97), BC (butyl carbitol, 2-(2-butoxy ethoxy) ethanol):$CS_2$(v/v 1:99), and BC:$CS_2$(v/v 3:97)). The results obtained were as follows : 1. Comparing the desorption efficiency of $CS_2$ with those of $CS_2$ with 1, 3, 5 % DMF and 1, 3 % BC cosolvents for two different groups of charcoal tubes each containing 8 different polar and non-polar organic solvents with 3 different concentration levels, the desorption efficiencies of the cosolvent-added $CS_2$ increased significantly for all polar organic solvents regardless of concentration levels tested. For non-polar organic solvents, no noticeable improvement was detected except xylene and trichloroethylene. The desorption efficiency of xylene increased significantly while that of trichloroethylene increased significantly at the lowest concentration level tested. 2. Either 5 % DMF or 3 % BC was the most suitable cosolvent because the desorption efficiency for non-polar organic solvent mixtures was similar or slightly improved compared with that of $CS_2$, while those of for polar organic solvent mixtures were above 75 % except for cyclohexanone. 3. The smallest variations in desorption efficiency represented by the ratio calculated from the maximum to minimum desorption efficiency for all concentration levels tested were found when 3 % BC was used as a cosolvent. The above results indicate that the desorption efficiency of $CS_2$ particularly for polar organic solvent mixtures collected on a charcoal tube can be significantly improved by the use of cosolvents such as 5 % DMF or 3 % BC. A caution, however, is in order for selecting a cosolvent whenever the cosolvent itself is being used in the workplace or the impurities contained in the cosolvent may interfere with the analytical results. In addition, to improve desorption efficiencies for such organic solvents as cyclohexanone or ketones, it is recommended to use suitable collection and desorption media other than the traditional method of charcoal tube collection/$CS_2$ desorption.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.1
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• pp.3-18
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• 1997

This study was conducted to evaluate desorption efficiencies by types of desorption solvent for polar and non-polar organic compounds collected on activated charcoal tubes. Analytes tested were toluene, m-xylene, isobutyl alcohol, n-butyl alcohol, cellosolve acetate, and butyl cellosolve. Three different concentration levels of spiked sample were made. Types of cosolvent mixed with the main solvent, $CS_2$, were methanol, pentanol, and dimethylformamide (DMF) and the cosolvent for methylenechloride was methanol. The amounts of cosolvent added to the main solvent were 1, 5, and 10% by volume (v/v%), respectively. The results were as follows: 1. For all mixed solvents except 1% methanol and 1% pentanol with $CS_2$, desorption efficiency significantly increased, compared with that of $CS_2$ alone. 2. Desorption efficiency increased by increasing analyte loading on charcoal tube regardless of mixed solvents used and the material polarity. 3. For all cosolvents mixed with $CS_2$ by 1% and 5% volume, desorption efficiency for non-polar compound was significantly higher than that of polar compound. For the 10% mixed solvents and the methylenechloride mixed with methanol, the results were opposite. 4. The lowest mean percent bias of 4.79% was obtained from the 5% DMF-$CS_2$ mixed solvent, followed by 4.82% from the 10% DMF-$CS_2$ solvent while the highest bias of 23.26% was from the solvent of $CS_2$ alone. Based on the results of this study, in order to increase desorption efficiency, it is recommended to add such cosolvents as methanol, pentanol, and DMF to $CS_2$, preferably 5% by volume for analyzing polar compounds collected in charcoal tubes.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.5 no.1
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• pp.104-118
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• 1995

This study was performed to evaluate factors affecting desorption of organic solvents collected on charcoal tube and to find out the optimum condition. Desorption efficiency for polar analytes was improved when several polar desorption solvents such as methanol, dimethylformamide(DMF), 2-(2-butoxyethoxy)ethanol were added to carbon disulfide($CS_2$). The best improvement was achieved when 10% dimethylformamide(DMF) in $CS_2$ was used as desorption solvent. During storage of polar analytes, recovery was greatly reduced. Especially, the recovery of cyclohexanone was decreased to 18.1 % after a month storage at $34^{\circ}C$. After two weeks storage, recovery of polar analytes was sharply decreased. Water adsorbed on charcoal interfered the recovery of polar analytes but didn't interfere that one of nonpolar solvent, toluene. When 10% DMF in $CS_2$ was used as desorption solvent, the effect of water on recovery was decreased, comparing with Desorption efficiency increased when analyte loading increased, and usage of 10% DMF in $CS_2$ decreased the loading effect. Increasing volume of desorption solvent was not effective to improve desorption efficiency of analytes when 10% DMF was used. Continuous shaking and sonication is not helpful to increase the desorption efficiency of analytes except cyclohexanone using 10% DMF. When silica gel used as adsorbent, methanol was better desorbent than dimethylsulfoxide. Analytes adsorbed on silica gel showed high recovery in low concentration and less affected by humidity. On the basis of this study, the following conclusions have been drawn. To improve the recovery of polar organic materials in air samples, it is necessary to analyze samples as soon as possible after they were collected. Otherwise, samples must be stored at low temperature. Using two components of desorption solvents, such as 10% DMF in $CS_2$, the effects of loading and humidity decreased for polar analytes such as methyl ethyl ketone and methyl isobutyl ketone. When work place has high humidity with low concentration of polar organic solvents, silica gel can be used as adsorbent, because it produces quantitative recovery for polar analytes at this condition. But it should be noted that high humidity makes breakthrough easy in silica gel samples.

• Membrane Journal
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• v.32 no.1
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• pp.50-56
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• 2022

In this work, the solvent permeation and separation performance of organic solvent nanofiltration (OSN) membranes were evaluated. Particularly, the PuraMem (PM) series developed for nonpolar solvents were analyzed and tested in dead-end filtration system. PM membranes exhibited higher permeance for nonpolar solvents compared to polar solvents, and their rejection data did not follow conventional trends with respect to solute size. The data showed that simple solution-diffusion model is not suitable to describe the OSN membrane behavior, and a better solvent-solute-membrane interaction parameter must be developed.

• Journal of environmental and Sanitary engineering
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• v.16 no.1
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• pp.72-90
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• 2001

This study was conducted to evaluate desorption efficiencies accuracy and precision by $CS_2$ and thermal desorption method for polar and non-polar organic solvents collected on activated carbon(AC), activated carbon fiber(ACF), carbosieve SIII, materials tested were Methyl alcohol, n-Hexane, Benzene, Trichloroethylene, Methyl isobutyl ketone and methyl cellosolve acetate and six different concentration levels of samples were made. The results were as follows ; 1. Accuracy on kind adsorbent and desorption method was low. In case of $CS_2$ desorption solvent, Overall B and Overall CV on AC and ACF were 43% and 6.63%, respectively. In case of thermal desorption method, accuracy of thermal desorption method appeared higher than solvent desorption method by AC 18.0%, 3.54%, ACF 2.6%, 2.57%, Carbosieve SIII 13.7% and 1.97%, respectively. 2. In the concentration level III, accuracy of thermal desorption method on adsorbent was in order as follow ; ACF > Carbosieve SIII > AC in the methyl alcohol and Carbosieve SIII > ACF > AC in the rest of them all subject material and Concentration levels showed good precision at EPA recommend standard (${\leq}{\;}30%$) 3. DEs by type of organic solvent adsorbent and desorption method are as follows ; In the case that desorption solvent is $CS_2$, DE of Methyl alcohol is AC 47.5%, DE of all materials is ACF about 50%. In the case of thermal desorption method, DE of Methyl alcohol is AC 82.0%, ACF 97.4%, Carbosieve SIII 86.3%. DE of the later case is prominently improved more than one of former. In particular, Except that DE of EGMEA is ACF 88.5%, DE of the rest of it is more than 95% which is recommend standard MDHS 72. With the result of this study, in order to measure various organic solvent occurring from the working environment, in the case of thermal desorption method, we can get the accurate exposure assessment, reduce the cost, and use ACF as thermal desorption sorbent which available with easy.

• Carbon letters
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• v.23
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• pp.55-62
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• 2017

We report on the dispersion state of partially reduced graphene oxide (PRGO) in organic solvents, namely methyl ethyl ketone, ethyl acetate, methylene chloride, toluene, and xylene, by controlling the carbon to oxygen (C/O) atomic ratio of the PRGOs. A two-phase solvent exchange method is also proposed to transfer PRGO from water to an aprotic solvent, such as methyl ethyl ketone. We achieve relatively good dispersion in aprotic and non-polar solvents by controlling the C/O atomic ratio of the PRGOs and applying the two-phase solvent exchange method. There is an increase in the glass transition temperatures with the dispersion of PRGOs into amorphous polymers, in particular a $4.4^{\circ}C$ increase for poly(methyl methacrylate) and $3.0^{\circ}C$ increase for polycarbonate. Good dispersion of PRGO in a nonpolar polymer, such as linear low density polyethylene, is also obtained.

• Journal of the Korean Chemical Society
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• v.12 no.1
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• pp.35-38
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• 1968

Radio iodination of various aromatic derivatives (aniline, toluene, iodobenzene, acetanilide, benzene, benzoic acid) were achieved at low temperature by a chloroamine-T procedures in presence of polar solvent(dioxane). Organic base (piperidine) was used as the catalyst. Iodine replacement reaction had occured on the aromatic or alicyclic ring by this reaction, and the kind and ratio of iodinated products were proved to be different from those of usual iodide reaction in organic solvent at low temperature. The reactivity of various aromatic or alicyclic compounds towards the present iodination system was evaluated and the scope and limitation of the present procedures in the preparation of radio pharmaceuticals were discussed.

• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.932-937
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• 2004

In situ extraction by organic solvent was studied in order to improve the recovery yield of hydrocarbon from the culture of Botryococcus braunii, a green colonial microalga. When the solvent mixture of octanol as an extractive solvent and n-octane as a biocompatible solvent was added to a two-phase column, the algal growth was seriously inhibited, even at a low concentration of polar octanol. Therefore, a two-stage cell-recycle extraction process was proposed to improve the contact area between the organic phase and the aqueous phase. The hydrocarbon recovery with in situ cell-recycle extraction showed a three-fold increase (57% of cell) in yield over that with two-phase extraction. In addition, over 60% of the hydrocarbon could be recovered without serious cell damage by downstream separation when this process was applied to the culture broth after batch fermentation.

• Rapid Communication in Photoscience
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• v.4 no.3
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• pp.67-69
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• 2015

FTIR spectroscopy has been employed to investigate the variation of anion-water hydrogen bonding in 1-butyl 3-methyl imidazolium tetrafluoroborate ([Bmim][$BF_4$]) ionic liquid caused by addition of organic co-solvents with various polarities. The variation was estimated by probing band shape and intensity of the OH stretching vibration of trace water present in ionic liquid at $3400-3800cm^{-1}$. The presence of polar aprotic co-solvent in ionic liquid dramatically reduces the absorptivity of the OH stretch band, indicating that the co-solvent changes the nature of anion-water hydrogen bond drastically, which might be responsible for the reduction of the viscosity of ionic liquid in the presence of the co-solvent.