• Analytical Science and Technology
• /
• v.15 no.3
• /
• pp.196-213
• /
• 2002

The alkylphenols, chlorophenols and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring mode followed by three work-up methods for comparison; EPA method, isoBOC derivatization method and TBDMS derivatization method. Eleven phenols in water samples were extracted with dichloromethane. Also, solid-phase extraction (SPE) with XAD-4 and subsequent conversion to isobutoxycarbonyl derivatives or tert.-butyldimethylsilyl derivatives for sensitive analysis with the selected ion-monitoring (SIM) mode. The recoveries were 85.1~109.9% (EPA method) and 90.3~126.6% (isoBOC derivatization and TBDMS derivatization), respectively. The method detection limit of bisphenol A for SIM were 0.732 ${\mu}g/{\ell}$ (EPA method), 0.002 ${\mu}g/{\ell}$ (isoBOC derivatization) and 0.021 ${\mu}g/{\ell}$ (TBDMS derivatization). The SIM responses were linear with the correlation coefficient varying 0.9755~0.9981 (isoBOC derivatization), and 0.9908~0.9996 (TBDMS derivatization). When these methods were applied to treated wastewater sample from a polyethylene plant, the concentrations of 11 phenols were below the method detection limit.

• The Korean Journal of Food And Nutrition
• /
• v.12 no.2
• /
• pp.191-191
• /
• 1999

A Purge & Trap Concentrator was used to analyze various volatile organic compounds(VOCs) in wat-er. The object of this study was to observe the purge efficiency of 40 VOCs in water according to the change of parameters (purge time drypurge time sample temperature) and to determine the optimum condition for VOCs using the purge & Trap concentrator interfaced with a narrow capillary connected to a gas chromatography/mass spectrometry. The optimum condition of purge and trap is as follows: purge time at 11min drypurge time at 5min sample temperature at 6$0^{\circ}C$ at constant purge flow (40mol/min) constant desorption flow(20ml/min) desorption temperature(2$25^{\circ}C$) and desorption time (1min) At this analytical condition the detection limits of VOCs was in the range of 0.1~0.5$\mu$g/ml and the purge efficiency of each compound was over 70%.

• Analytical Science and Technology
• /
• v.16 no.6
• /
• pp.458-465
• /
• 2003

The HS (headspace)-SPME (Solid phase microextraction) as rapid and simple method was performed for the determination of volatile fatty acids (VFAs) from the aqueous samples. In-fiber derivatization of VFAs with 1-Pyrenyldiazomethane (PDAM) was applied to improve their sensitivity of detection. In SPME procedure, typical parameters such as effects of solution pH, and salting out reagent and ultrasonication were investigated to improve the extraction efficiency. Based on the developed method, VFAs in wastewater samples were determined by gas chromatography / mass spectrometry-selected ion monitoring (GC/MS-SIM) mode.

• Environmental Analysis Health and Toxicology
• /
• v.20 no.1
• /
• pp.47-55
• /
• 2005

본 연구는 GC/MS를 이용하여 수질, 토양 및 저질 시료 중의 benzo(a)pyrene(BaP)을 분석하는 방법을 확립하고자 하였다. BaP은 수질 시료(100mL)에서 n-hexane으로 추출하였으며, 토양 및 저질 시료(l0g) 에서는 먼저 메탄올로 추출한 후 hexane으로 다시 추출하여 농축시켜 분석하였다. 수질 시료 중의 BaP 회수율은 94.8% 이상이었으며 토양에서의 회수율은 약 93％를 보였고 재현성은 10.49% 이하였다. 검정 곡선은 상관계수(R²)값이 수질과 토양 모두에서 0.996 이상의 좋은 직선성을 보여주었다. 토양 시료의 경우 35지역 중 6지역의 토양에서 0.5～223.5㎍/kg의 농도 범위로 BaP가 검출되었으며 수질과 저질 시료에서는 모든 지역에서 검출한계 이하로 나타났다. 이 분석방법은 환경 중에 미량으로 존재하는 BaP의 분석과 모니터링에 유용하게 사용할 수 있는 적합한 방법이라 사료된다.

• Environmental Analysis Health and Toxicology
• /
• v.20 no.2 s.49
• /
• pp.123-131
• /
• 2005

본 연구는 GC/MS를 이용하여 수질, 토양 및 저질 시료 중의 4-Nitrotoluene(4-NT)을 분석하는 방법을 확립하고자 하였다. 4-NT은 수질 시료(100mL)에서 n-hexane으로 추출하였으며, 토양 및 저질 시료(10g)에서는 먼저 메탄올로 추출한 후 hexane으로 다시 추출하여 농축시켜 분석하였다. 수질 시료 중의 4-NT의 회수율은 $99.1\%$ 이상이였으며 토양에서의 회수율(recovery)은 약 $110\%$를 보였고 재현성 (relative standard deviation)은 $11.99\%$ 이하였다. 검정곡선은 상관계수$(R^2)$값이 수질과 토양 모두에서 0.994이상의 좋은 직선성을 보여주었다. 본 연구에서 채취한 수질 43개 지역, 토양 35개 지역 및 저질 11개 지역의 모든 시료에서 4-NT은 검출한계 이하로 나타났다. 이 분석방법은 환경 중에 미량으로 존재하는 4-NT의 분석과 모니터링에 유용하게 사용할 수 있는 적합한 방법이라 사료된다.

• Analytical Science and Technology
• /
• v.12 no.5
• /
• pp.408-414
• /
• 1999

A selective and sensitive method for the derivatization of total homocysteine (Hcy) and the related compounds in plasma by gas chromatograph (GC)-electron capture detector (ECD) has been developed. To determine total homocysteine, cysteine (Cys), and methionine (Met) in human plasma using GC-ECD, analytes were reduced and converted into their N(O,S)-ethylearbonyl pentafluoropropyl (PFP) ester by derivatization with ethyl chloroformate and pentafluoropropyl alcohol (PFP-OH) in plasma. The best derivatizing agent N(O,S)-ethyl carbonyl PFP ester, was chosen by comparing the sensitivity of derivatized analysis in GC-ECD. The derivatized analytes in plasma were extracted by chloroform, and subsequently back-extracted with hexane and analyzed by GC-ECD. The calibration carves ($R^2$ > 0.990) were linear over the range $5-50{\mu}mol/L$ of Hcy and Met, $40-400{\mu}mol/L$ of Cys spiked in plasma. The detection limit observed by the established method was below $0.5{\mu}mol/L$. This method is highly sensitive and specific in the analysis of Hcy, Cys, and Met. Therefore, we suggest that this method is appropriate in the analysis of trace concentration of Hcy, Cys, and Met in biological fluids.

• Analytical Science and Technology
• /
• v.31 no.1
• /
• pp.23-30
• /
• 2018

Twenty-two allergy-induced aromatics in children were analyzed using a gas chromatography flame ionization detector (GC-FID) and gas chromatography mass spectrometer (GC-MSD). Analytes were extracted using an automatic Soxhlet extractor and centrifuged for 10 min in a fast freezing centrifuge, and the supernatant was transferred into a 2 mL vial and injected in split mode. Under the established conditions, the calibration curve showed linearity with a correlation coefficient of 0.996 or more. A wide range of sensitivity of 6.7 to 1,859,839 depending on the device characteristics and detector used was shown. The detection limit of the device was 0.0032 to $0.0335{\mu}g/mL$, and the maximum detection limit was less than $0.1{\mu}g/mL$. The detection limit of the method ranged from 0.0033 to $0.1161{\mu}g/mL$. In addition, the limit of quantification ranged from 0.0100 to $0.5422{\mu}g/mL$, with a level of precision ranging from 0.21 % to 4.89 % and a degree of accuracy ranging from 89 % to 111 %. The analytical method developed in this study was applied to commercial products.

• Applied Chemistry for Engineering
• /
• v.26 no.3
• /
• pp.311-318
• /
• 2015

This work investigated the plasma treatment of aqueous bisphenol A (BPA) solution and mineralization pathways. For the effective contact between plasmatic gas and aqueous BPA solution, the plasma was created inside a porous ceramic tube, which was uniformly dispersed into the aqueous solution through micro-pores of the ceramic tube. Effects of the gas flow rate, applied voltage and treatment time on the decomposition of BPA were examined, and analyses using ultraviolet (UV) spectroscopy, ion chromatography and gas chromatography-mass spectrometry were also performed to elucidate mineralization mechanisms. The appropriate gas flow rate was around $1.0L\;min^{-1}$; when the gas flow rate was too high or too low, the BPA decomposition performance at a given electric power decreased. The increase in the voltage improves the BPA decomposition due to the increased electric power, but the energy required to remove BPA was similar, regardless of the voltage. Under the condition of $1.0L\;min^{-1}$ and 20.8 kV, BPA at an initial concentration of $10L\;min^{-1}$ (volume : 1 L) was successfully treated within 30 min. The intermediates produced by the attack of ozone and hydroxyl radicals on BPA were further oxidized to stable compounds such as acetate, formate and oxalate.

• Clean Technology
• /
• v.18 no.2
• /
• pp.191-199
• /
• 2012

In order to reduce or remove off-flavor and volatile organic compounds (VOCs) from Laminaria japonica effectively, continuous treatment process by supercritical carbon dioxide (SC-$CO_2$) was applied. After freeze-drying, Laminaria japonica powdered with $710{\mu}m$ was used. Experiments were carried out at temperature range from 35 to $55^{\circ}C$, and pressure range from 10 to 25 MPa for evaluation of SC-$CO_2$ treatment effect. Flow rate of carbon dioxide used in this reseach was constantly fixed at 26.81 g/min. Before and after treatment of SC-$CO_2$, off-flavor and VOCs from Laminaria japonica were analyzed by gas chromatography-mass spectrometry detector (GC-MSD). Total 47 VOCs emitted from Laminaria japonica were identified before treatment of SC-$CO_2$, major components of seaweed smell (ordor) in Laminaria japonica were identified as alcohols, aldehydes, ester and acids, ketone, halogenated compounds and hydrocarbon. Off-flavor and VOCs in all experimental conditions was reduced or removed after SC-$CO_2$ treatment. Among the experimental conditions, the highest removal yield was at 25 MPa and $55^{\circ}C$.

• Journal of Applied Biological Chemistry
• /
• v.58 no.2
• /
• pp.175-181
• /
• 2015

Compositions of essential oils extracted from mint herb such as Mentha piperita, Mentha spicata, and Mentha ${\times}$ piperita var. citrate produced in Jeju were analyzed using gas chromatography-mass spectrometry (GC-MS) and headspace-GC-MS (HS-GC-MS). By the GC-MS analysis, 13 compounds were tentatively identified in Mentha piperita, Mentha spicata, and Mentha ${\times}$ piperita var. citrate, respectively. Peperitenone oxide, carvone, and linalool were detected as major compounds in Mentha piperita, in Mentha spicata, in Mentha ${\times}$ piperita var. citrate, respectively, based on the ratio of peak intensity in the total ion chromatogram. The greater number of compounds, including volatile alcohols and acetates were identified by HS-GC-MsS than by GC-MS in these all three essential oils. Similar patterns of composition were detected in both Mentha spicata and Mentha ${\times}$ piperita var. citrate by either one of GC-MS methods. However, in case of Mentha piperita, $\small{L}$-(-)-menthol, which was identified as the major compound by HS-GC-MS was detected in dramatically reduced quantity by GC-MS. Interestingly, we found that both linalyl acetate and linalool were identified as the dominant compounds in the essential oil of Mentha ${\times}$ piperita var. citrate.