• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.16 no.3
• /
• pp.211-221
• /
• 2006

This study was performed to compare with desorption efficiency and storage stability of CSC and CMS tubes for Ketones in workplace air. 1. The best desorbing solution for CSC tube was 1 % or 3 % dimethylformamide(DMF) in carbon disulfide($CS_2$). The desorption efficiencies were 96.40 % for cyclohexanone, 94.86 % for acetone, 96.96 % for methyl ethyl ketone(MEK), 103.44 % for methyl isobutyl ketone(MIBK), 100.17 % for methyl amyl ketone(MAK), 100.43 % for methyl butyl ketone(MBK), 97.01 % for toluene and 99.33 % for trichloroethylene(TCE). 2. The best desorbing solution for CMS tube was 1 % or 3 % DMF in $CS_2$. The desorption efficiencies were 96.42 % for cyclohexanone, 98.53 % for acetone, 99.67 % for MEK, 105.48 % for MIBK, 100.13 % for MAK, 100.13 % for MBK, 95.42 % for toluene and 98.15 % for TCE. 3. In the storage condition at room temperature($20^{\circ}C$), the recovery rates of cyclohexanone and MEK on CSC tube were rapidly decreased 30.9 % and 50.9 % after 4 weeks, respectively. The recovery rates of all of 6 ketones and 2 nonpolar solvents were shown over 80 % after 1 week in the storage condition of refrigerate temperature($-4^{\circ}C$), and were kept over 80 % after 4 weeks in the storage condition of freezer temperature($-20^{\circ}C$). 4. The recovery rates of cyclohexanone on CMS tube were 80.6 % for 1 week after and 60.5 % for 4 weeks after at room temperature($20^{\circ}C$). The recovery rates of cyclohexanone were shown 80.6 % for 1 week after and 60.5 % for 4 weeks after at $-4^{\circ}C$, and of 6 ketones and 2 non-polar solvents were kept stable over 85 % at $-4^{\circ}C$ and over 97 % at $-20^{\circ}C$ for 4 weeks after. In conclusion, the best desorbing solution was 1 % or 3 % DMF in $CS_2$ and more appropriate sorbent tube for ketones and non-polar solvents was CMS than CSC. We recommend CSC tube would be useful if the samples analyzed within 1 week because CMS tubes are more expensive than CSC tubes. However, if the storage time is needed more than 3 weeks, CMS tubes should be suitable and the storage condition should be below $-20^{\circ}C$.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.11 no.1
• /
• pp.17-25
• /
• 2001

The purpose of this study is to substitute water-based painting materials for the current solvent-based ones used in motor-repairing process to minimize the exposure of organic solvents to the painters. This study assessed the exposure of organic solvents to the painters using water-based and solvent-based painting materials and compared compositions, painting processes and the health hazards of the application of these alternative painting mate rials. The results of this study are as follows. 1. solvent-based painting materials used in motor-repairing process consist of various organic solvents, which consist primarily of toluene, xylene, ethyl benzene, ethyl methyl benzene, trimethyl benzene, ethyl acetate, butyl acetate, methyl isobutyl ketone, 2-ethoxy ethanol, 2-ethoxy ethyl acetate and toluene-2,4-diisocianate and the others. These organic solvents are known as health-hazardous substances. But water-based painting materials are high-solid, low-solvent one sand consist of such two organic solvents as 2-butoxy ethanol and 2-heptanone and the others. 2. The painters us ing solvent-based painting mate rials in motor-repairing process are exposed to various organic solvents which consist of toluene, xylene, ethyl acetate, butyl acetate, methyl isobutyl ketone, trimethyl benzene, 2-ethoxy ethanol, and 2-ethoxy ethyl acetate. But the painters using solvent-based ones are only exposed to 2-butoxy ethanol and 2-heptanone. 3. By using water-based painting materials in stead of solvent-based painting materials containing health-hazardous organic solvents, the exposure of such organic solvents in the painter's breathing zone can be largely prevented. 4. This study recommends water-based painting materials as substitutes for the current solvent-based ones used in motor-repairing process to minimize the exposure of organic solvents to the painters.

• Journal of Environmental Science International
• /
• v.7 no.6
• /
• pp.753-759
• /
• 1998

In physical and reactive extraction of acrylic acid using various solvents the equilibrium characteristics of extraction were investigated. The degree of extraction in reactive extraction with Tri-n-octylamine(TOA) was 1.5~3 times than that in physical extraction. Distribution ratio was constant in methyl isobutyl ketone(MIBK) and n-butylacetate(n-BAc) but was increased with increasing the concentration of acrylic acid in benzene and chloroform. It can be explained by formation of dimers. Maximum extraction leadings of acrylic acid were three in benzene and were two in MIBK, chloroform and n-BAc, and it was found that acrylic acid was extracted as the form of $A_3$R In benzene and $A_2R$ in MIBK, chloroform and n-BAc. In effect of solvent, the degree of extraction was increased as he difference of solubility parameter of solvent and solute was decreased, and as dielectric constant of solvent was increased.

• YAKHAK HOEJI
• /
• v.26 no.4
• /
• pp.257-260
• /
• 1982

Measurement of water is a subject of continued interest. High resolution proton magnetic resonance has not been very effective in the determination of water. Especially spectral overlap with other proton signals from the sample is undesirable result. However, trifluoroacetic anhydride reacts with water and forms trifluoroacetic acid and the proton signal of trifluoroacetic acid did not overlap with that of samples. By use of this fact, water in acetone, ethyl ether, dioxane, dichloroethane and methyl isobutyl ketone is analyzed by high resolution proton magnetic resonance (PMR). This method is capable of detecting as little as 200ppm of $H_{2}O$. And it is very rapid, simple and accurate.

• 한국생물공학회:학술대회논문집
• /
• 2001.11a
• /
• pp.552-555
• /
• 2001

This work reported concerns the removal of mixtures of methyl ethyl ketone (MEKJ, methyl isobutyl ketone (MIBK) and BTXs, which find wide application as industrial solvents, using the biofilter by the microbial consortium, The biofilter was constructed from acryl columns and was 400 mm in length and 55 mm in diameter and the height of fibrous packing material which made of PVC was 160 111111, 8 seconds of the retention time, pH 6.5 - 7.5 and the initial inlet concentration of MEK, MIBK and BTXs were 220 ppm. The removal efficiency of the gaseous mixtures was relatively low during the initial 2 days after inoculum of the microbial consortium, after 3 days, however, the efficiency was increased remarkably. In this study, The removal efficiency of the biofilter for the mixtures show the high degree from one day after inoculum of the microbial consortium, having no relation to the fluctuation of the inlet concentration of MEK, MIBK and BTXs.

• Journal of Korean Society for Atmospheric Environment
• /
• v.25 no.6
• /
• pp.503-511
• /
• 2009

VOC mixture was fed to a trickle bed air biofilter (TBAB) with step-change in influent mixture concentrations from 50 ppmv to 1,000 ppmv, corresponding to loadings of $5.7\;g/m^3/hr$ to $114.1\;g/m^3/hr$. VOC mixture was an equimolar ratio of two aromatic VOCs, i.e., toluene and styrene, and two oxygenated VOCs, i.e., methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK). The TBAB system employed backwashing as biomass control. The experimental results showed that a critical loading rate for VOC mixture removal was determined to be about $60\;g/m^3/hr$, and critical loading rates for individual VOCs in the mixture were different. Specifically, toluene content in the mixture played a major role in the biofilter overall performance. As VOC mixture was fed beyond the critical loading rate, reacclimation of the biofilter to reach the 99% removal efficiency following backwashing was delayed, which was a critical factor in the biofilter performance. In the mass balance analysis, 63.8% of the carbon equivalent in VOCs removal was used for $CO_2$ production during the experimental runs. The 82.6% nitrogen utilized in the biofilter was contributed to microbial cell synthesis. The obtained results were compared against consistently high efficient performance of TBAB for VOC mixture by employing backwashing as biomass control.

• Journal of the Korean Chemical Society
• /
• v.43 no.6
• /
• pp.644-650
• /
• 1999

Trace amount of cobalt in water samples was preconcentrated continuously with an organic precipitant and determined by flame atomic absorption spectrometry. The flow injection technique was used to preconcentrate cobalt by on-line direct precipitation with 1-nitroso-2-naphthol. The precipitation was dissolved with methyl isobutyl ketone (MlBK) and was sent to the flame. The optimum conditions for cobalt determination were determined and used to analyze Co samples. For 1.0 mL of sample, the enrichment factor was 13 and the sample throughput was about lO per hour for 0.5 ppm Co solution. The enrichment factor was increased to 68 fold for 10.0 mL. A semi-reference biologicaI sample was prepared and analyzed. The result was in good agreement with the expected value with RSD of 4%.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.15 no.3
• /
• pp.261-269
• /
• 2005

To investigate the field applicability of a diffusive sampler (3M OVM #3500, passive sampling method) authors conducted a simultaneous measurement of personal organic solvents exposure in the air of the workplaces by charcoal tube with low volume sampler (active sampling method) and diffusive sampler. Samples were collected and analyzed by NIOSH method ($NMAM^{(R)}$) from thirty-eight workers in 12 factories who work in 6 different processes. Geometric mean (GM) and geometric standard deviation (GSD) were used to describe the result. To compare the results of the two methods, paired t-test was used. According to the manual of the exposure assessment of the mixed organic solvents (Ministry of Labor, Korea), Em was calculated. Simple linear regression was used to evaluate the relationship between the two methods. Results were as follows; 1. Eight different solvents (ethyl acetate, n-hexane, toluene, xylene, acetone, isopropyl alcohol, methyl ethyl ketone (MEK), and methyl isobutyl ketone) were detected simultaneously in the two methods and the concentrations of the personal exposure were lower than 0.5 TLV level. The concentration of the charcoal tube method was higher than that of a diffusive sampler in n-hexane and MEK (p<0.05). 2. Em of the charcoal tube method was higher than that of diffusive sampler method but not significantly different and was lower than the OEL (Occupational Exposure Limit) in all 6 processes. 3. There was a significant correlation between the two methods in low concentrations of the 8 organic solvents (p<0.05). In conclusion, there was no difference in charcoal tube method and diffusive sampler method in low concentrations of some organic solvents, diffusive sampler can be applied to assess the personal monitoring in low level exposure.

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

• Analytical Science and Technology
• /
• v.15 no.2
• /
• pp.127-134
• /
• 2002

Analytical method to determine rare earth elements which were extracted to organic phase by inductively coupled plasma mass spectrometry(ICP-MS) was investigated. Organic phase which had extracted rare earth elements was directly aspirated into ICP-MS by ultrasonic nebulizer(USN) in order to reduce solvent load to the plasma. Then, the count rate increased when MIBK(methyl isobutyl ketone) was added to EtOH(ethanol) but decreased when 0.03 M HEH(2-ethylhexyl-2-ethylhexyl phosphonic acid, $P_{507}$, PC88A) was added to solvent which mixed MIBK with EtOH. The optimal temperatures of desolvation system were -10 $^{\circ}C$ for the condenser and 150 $^{\circ}C$ for the heating tube. The optimal nebulizer flow rate which gave maximum count rate and minimum reflect power was 0.7 L/min. The optimal pH and extraction time were 4.3 and 10 min for MIBK-0.03 M HEH system. Detection limits which were obtained through calibration curves at the range of 0.2 ${\sim}$ 20 ng/mL were 0.02 ${\sim}$ 0.05 ng/mL under the optimal experimental conditions.