• Analytical Science and Technology
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• v.15 no.3
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• pp.300-316
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• 2002

The extraction methods of PBBs from environmental samples by soxhlet extraction for solid phase and liquid-liquid extraction for liquid phase were compared. After extraction, silicagel and florisil as column clean up methods were used for the comparison of cleanup efficiency with different solvent system. Also, the analytical instruments were used GC/MSD. The 22 kinds of PBBs standards were used to establish the analytical methods to perform the experiments of recoveries and detection limits in water and soil. The detection limits of PBBs represented 5~10 ng/L for water and 0.5~3.5 ng/g for soil samples, respectively. The recoveries of water samples represented 96~107% in n-hexane, dichloromethane and toluene for water, and 60~80% in combined solvent with n-hexane and acetone. The recoveries of soil sample were surveyed 67~97% in soxhlet extraction and 64~76% in ultrasonic extraction with selected solvents.

• Advances in environmental research
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• v.4 no.1
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• pp.39-48
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• 2015

Bisphenol A is widely used in plastic and other industrial consumer products. Release of bisphenol A and its analogues into the aquatic environment during manufacture, use and disposal has been a great scientific and public concern due to their toxicity and endocrine disrupting effects on aquatic wildlife and even human beings. More recent studies have shown that these alkylphenols may affect the molting processes and survival of crustacean species such as American lobster, crab and shrimp. In this study, we have developed gas chromatography with flame ionization detection (GC-FID) and gas chromatography-mass spectrometric (GC-MS) methods for the determination of bisphenol A and its analogues in shrimp Macrobrachium rosenbergii, blue crab Callinectes sapidus and American lobster Homarus americanus samples. Bisphenol A, 2,4-bis-(dimethylbenzyl)phenol and 4-cumylphenol were found in shrimp in the concentration ranges of 0.67-5.51, 0.36-1.61, and < LOD (the limit of detection)-1.96 ng/g (wet weight), and in crab of 0.10-0.44, 0.13-0.62, and 0.26-0.58 ng/g (wet weight), respectively. In lobster tissue samples, bisphenol A, 2-t-butyl-4-(dimethylbenzyl)phenol, 2,6-bis-(t-butyl)-4-(dimethylbenzyl)phenol, 2,4-bis-(dimethybenzyl)phenol, 2,4-bis-(dimethylbenzyl)-6-t-butylphenol and 4-cumylphenol were determined at the concentration ranges of 4.48-7.01, 1.23-2.63, 2.71-9.10, 0.35-0.91, 0.64-3.25, and 0.44-1.00 ng/g (wet weight), respectively. At these concentration levels, BPA and its analogs may interfere the reproduction and development of crustaceans, such as larval survival, molting, metamorphosis and shell hardening.

• Journal of Convergence for Information Technology
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• v.7 no.4
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• pp.91-96
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• 2017

In this paper, we aim to respond efficiently to crime by using Arduino and smartphone apps in response to increasing number of house-breaking crimes. It receives the signal of the sensor installed in the house and connects it with the app of the smartphone. To use the app, you can download the app from the user's smartphone, launch the app, and operate the operation outside the home, not only inside the house, by linking the executed app. Among the sensors installed in the house, the movement detection sensor is used to enhance the security, and the gas leakage sensor and the flame detection sensor can be used to easily detect the risk of fire and to prevent the fire early. Security is further enhanced by the ability to remotely control the front door with a smartphone. After that, various sensors can be added and it can be developed as a WiFi module in addition to the Bluetooth module.

• Analytical Science and Technology
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• v.16 no.3
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• pp.240-248
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• 2003

Sulfur compounds which are well-known odor-active compounds in industrial area have very low detection threshold values. Trace amounts of volatile sulfur compounds in enviroment air around several odor sources were concentrated in liquid argon bath and determined by gas chromatograph with flame photometric detector (FPD) which exhibits very good selectivity and sensitivity. 25% ${\beta}$,${\beta}$-Oxydipropionitrile on 60/80 Chromosorb W was used as adsorbent for the preconcentration of sulfur compounds in air sample and also as packing material for a packed glass column. Concentration volume of air sample was different from place to place in the range of 0.1~3.0L. Atmospheric concentrations of sulfur compounds in air of residential districts and boundaries of business establishments, and also those in the exhausted gases of emission points such as a sewage disposal plant in industrial area were measured.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.1
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• pp.34-39
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• 2023

Objectives: In this study, the safety of alcohol-based hand sanitizers (ABHSs) for quasi-drugs and cosmetics was investigated by analyzing the ethanol content, which is an active ingredient with a sterilizing effect, and methanol, which is toxic. Methods: Forty-one ABHSs were purchased at large supermarkets and online stores. Ethanol quantification was performed by gas chromatography-flame ionization detector, and methanol quantification was performed by headspace-gas chromatography-mass spectrometry. Results: The ethanol content of ABHS in quasi-drugs was 49.6-67.8%, which was suitable for standard manufacturing procedures for external disinfectants, and the ethanol content of ABHS in cosmetics was 9.1-61.3%. The methanol content of ABHS in quasi-drugs ranged from not detected(N.D.)-131.8 ppm, which was suitable for the methanol detection standard of ethanol raw materials in the Korean Pharmacopoeia. The methanol content of ABHS in cosmetics was 23.4-859.7 ppm, which was suitable for the detection limit of methanol in cosmetics. Conclusions: The ethanol and methanol content of ABHS was judged to be safe. When selecting an ABHS to be used for sterilization, it seems necessary to check the content of ethanol, an active ingredient, and use it according to its intended purpose.

• Journal of the Korean Chemical Society
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• v.52 no.2
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• pp.148-154
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• 2008

A simple and fast method for extraction and determination of trace amounts of copper(II) ions using octadecyl-bonded silica membrane disks modified with 2-propylpiperidine-1-carbodithioate (PPCD)I and atomic absorption spectrometry (AAS) is introduced. Extraction efficiency and the influence of flow rates, pH, and type and smallest amount of stripping acid were investigated. Maximum capacity of the membrane disks modified with 2 mg of the anthraquinone derivative used was found to be 425μg Cu2+. The limit of detection of the proposed method is 7 ng/ml. The method is applied to the recovery of Cu2+ from different synthetic samples and a spring water sample.

• Journal of the Korean Chemical Society
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• v.52 no.2
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• pp.155-163
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• 2008

.A simple and reproducible method for the rapid extraction and determination of trace amounts of copper(II) ions using mesoporous organo-silicas mesoporous silica and atomic absorption spectrometry is presented. Common coexisting ions did not interfere with the separation and determination. The preconcentration factor was 100 (1 ml elution volume) for a 100 ml sample volume. The limit of detection of the proposed method is 1.0 ng ml-1. The maximum sorption capacity of sorbent under optimum conditions has been found to be 5mg of copper per gram of sorbent. The relative standard deviation under optimum conditions was 2.8% (n=10). Accuracy and application of the method was estimated by using test samples of natural and synthetic water spiked with different amounts of copper(II) ion.

• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.636-647
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• 2016

Magnetite nanoparticles ($Fe_3O_4$ NPs) were synthesized by co-precipitating method under optimized condition. The $Fe_3O_4$ NPs coated with sodium dodecyl sulfate-thenoyltrifluoroacetone ($Fe_3O_4$ NPs-SDS-TTFA) were then exerted as the magnetic solid phase extraction (MSPE) adsorbent for the extraction process prior to introducing to a flame atomic adsorption spectrometry (FAAS). The synthesized $Fe_3O_4$ NPs-SDS-TTFA were applied for the extraction of Pb(II) ions from different water samples. The characterization studies of nanoparticles were performed via scanning electron microscopy-energy dispersive micro-analysis (SEM-EDAX), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) techniques. The substantial parameters affecting the extraction efficiency were surveyed and optimized. A dynamic linear range (DLR) of $10-400{\mu}g\;L^{-1}$ was obtained and the limit of detection (LOD, n=7) and relative standard deviation (RSD%, n= 6, $C=20{\mu}g\;L^{-1}$) were found to be $2.3{\mu}g\;L^{-1}$ and 1.9%, respectively. According to the results, the proposed method successfully applied for the extraction of Pb(II) ions from different environmental water samples and satisfactory results achieved.

• Bulletin of the Korean Chemical Society
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• v.27 no.5
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• pp.725-732
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• 2006

A rapid flotation methodology for zinc(II) separation and enrichment from human biofluids is established. At pH 6.0 and ambient temperature, using oleic acid (HOL) as a foaming reagent, zinc(II) was separated with phenanthraquinone monophenyl thiosemicarbazone (PPT) as a new flotation collector for Zn(II). The floated red colored 1 : 2 Zn(II)-PPT complex was measured spectrophotometrically at 526 nm with a molar absorptivity of $1.83 \;{\times}\; 10^5\; L$ mol $L ^{-1}\;cm ^{-1}$. Beer's law was obeyed over a concentration range 0.05-1.0 mg $L ^{-1}$ in the aqueous as well as in the scum layers. The proposed preconcentration flotation methodology was applied to determine Zn(II) in human biofluids. Application was, also, extended to determine Zn(II) in pharmaceutical samples and natural water samples spiked with known amounts of Zn(II) with a preconcentration factor of 100 and a detection limit of 10 ng m$L ^{-1}$. The method was verified by comparison of the spectrophotometric results with flame atomic absorption spectrometric (AAS) measurements. Moreover a postulation for the mechanism of flotation is proposed.

• Bulletin of the Korean Chemical Society
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• v.27 no.5
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• pp.694-698
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• 2006

A method has been described for the chemical speciation, preconcentration and determination of Cr(III) and Cr(VI) species in filtered tannery waste waters by flame atomic absorption spectrometry using ion-exchange resins. Amberlite IR-120($H^+$) strongly acidic cation exchanger and Amberlite IRA-410($CI ^-$) strongly basic anion exchanger resins were used for the separation and preconcentration of Cr(III) and Cr(VI) species, respectively. Optimum condition for preconcentration and speciation was obtained by testing pH of sample and eluent, flow rates of sample and eluent, amount of resins, volume of sample and eluents, and effect of foreign ions. The recommended method has been successfully applied for the preconcentration and determination of chromium species in the dissolved phase of waste water samples collected from a tannery waste water treatment plant in Kayseri, Turkey. The detection limits achieved were 0.73 $\mu$g/L for Cr(III) and 0.81 $\mu$g/L for Cr(VI). Recovery studies showed 99% for Cr(III) and 98% for Cr(VI), for samples spiked with single species.