• 한국대기환경학회지
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• 제18권6호
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• pp.527-538
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• 2002

In this study, the performance of sampling and of analytical methodology was examined against a number of selected volatile organic compounds (VOCs) in the ambient air. The canister-based sampling method for VOCs has been a viable and widely used approach that is based on research and evaluation performed over the past several years. VOCs were determined using canisters by GCMSD analysis. A total of target analyses in this study included approximately 30 VOCs designated in TO-l4A categories including BTEX. The methodology for QC(quality control) was intensively investigated with a wide range of performance criteria such as; (1) cleanliness of canisters, (2) reproducibility of diluter, (3) instrumental detection limits of preconcentrator and GCMSD, and (4) precision and accuracy of GCMSD. For most of the compounds tested, precision was less than $\pm$5%, IDL was 0.2 ppbv, accuracy was $\pm$5%, respectively. This study demonstrated that the combination of canister sampling and GC/MSD analysis could be reliably applied to the measurements of BTEX in ppbv levels that are typically observed in/outdoor air environment.

• Mass Spectrometry Letters
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• 제1권1호
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• pp.29-32
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• 2010

Cross reacting antibodies can cause an overestimation of the results of immunoassays. Therefore, alternative methods are needed for the accurate quantification of steroids. Gas chromatography combined with isotope-dilution mass spectrometry (GC-IDMS) is developed to quantify urinary active androgens, testosterone, epitestosterone and dihydrotestosterone, which are clinically relevant androgens to both hair-loss and prostate diseases. The method devised involves enzymatic hydrolysis with $\beta$-glucuronidase, solid-phase extraction, liquid-liquid extraction using methyl tert-butyl ether and subsequent conversion to pentafluorophenyldimethylsilyl-trimethylsilyl (flophemesyl-TMS) derivatives for sensitive and selective analysis in selected-ion monitoring mode. Flophemesyl-TMS derivatization not only eliminates matrix interference but also has a good peak resolution within a 6 min-run. A selective and sensitive GC technique with flophemesyl-TMS derivatives also allows accurate quantitative analysis of three active androgens when combined with IDMS. The limit of quantification of the three analytes was <50 pg/mL, and extraction recoveries ranged from 91.9 to 102.1%. The precision and accuracy were 1.2~6.5% and 89.0~106.7%, respectively. This GC-IDMS method can be useful for evaluating the drug efficacy and monitoring the biological processes responsible for male-pattern baldness and prostate diseases.

• Bulletin of the Korean Chemical Society
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• 제30권10호
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• pp.2287-2293
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• 2009

Gas Chromatography-Mass Spectrometry (GC-MS) fingerprint analysis, Principle Components Analysis (PCA), and Hierarchical Cluster Analysis (HCA) were introduced for quality assessment of Curcuma longa L. (C. longa). The GC-MS fingerprint method was developed and validated by analyzing 33 batches of samples of C. longa from different geographic locations. 18 chromatographic peaks were selected as characteristic peaks and their relative peak areas (RPA) were calculated for quantitative expression. Two principal components (PCs) were extracted by PCA. C. longa collected from Guizhou and Fujian were separated from other samples by PC1, capturing 71.83% of variance. While, PC2 contributed for their further separation, capturing 11.13% of variance. HCA confirmed the result of PCA analysis. Therefore, GC-MS fingerprint study with chemometric techniques provides a very flexible and reliable method for quality assessment of C. longa.

• 약학회지
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• 제51권3호
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• pp.206-213
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• 2007

Recently estimating the uncertainty of an analytical result has become an essential part of quantitative analysis. This study describes the uncertainty of the measurement for the determination of methamphetamine and its major metabolite amphetamine in human hair, The method consists of washing, drying, weighing, incubation and extraction with methanolic HCI solution, clean-up, trifluoroacetyl derivatization, and qualification/quantification of residues by gas chromatography/mass spectrometry (GC/MS). Traceability of measurement was established through traceable standards and calibrated volumetric equipment and measuring instruments. Measurement uncertainty associated with each analyte in real samples was estimated using quality control (QC) data. The main source of combined standard uncertainty comprised two components, which are uncertainties associated with calibration linearity and variations in QC, while those associated with preparation of analytical standards and sample weighing were not so important considering the degree of contribution. Relative combined standard uncertainties associated with the described method ranged for individual analytes from 4.99 to5.03%.

• 분석과학
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• 제14권6호
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• pp.471-475
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• 2001

$85{\mu}m$-polyacrylate(PA) 와 $100{\mu}m$-polydimethylsiloxane(PDMS) fiber를 사용하여 물증의 DBCP와 n-butylbenzene을 추출한 후 GC-MS로 분석하는 방법을 연구하였다. SPME 과정에 영향을 미치는 인자들, 즉 추출 시간, 주입 길이, 주입 온도, 탈착 시간 및 탈착 온도들에 대한 최적화 조건을 조사하였다. 검량선의 직선성(correlation coefficient, R)은 0.99 이상이었으며, 본 분석법의 검출한계는 1.5 와 $10.8{\mu}g/L$ 이었고, 분석법의 재현성은 RSD 10.4와 14.4 % 였다.

• Archives of Pharmacal Research
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• 제26권9호
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• pp.697-705
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• 2003

The alkylphenols, chlorophenols, and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring (GC/MS-SIM) followed by two work-up methods for comparison: isobutoxycarbonyl (isoBOC) derivatization and tert-butyldimethylsilyl (TBDMS) derivatization. Eleven endocrine disrupting chemicals (EDCs) of phenols in biological samples were extracted with acetonitrile and then the acetonitrile layer underwent freezing filtration 6$0^{\circ}C$ for 2 hours. Solid-phase extraction (SPE) was used with XAD-4 and subsequent conversion to isoBOC or TBDMS derivatives for sensitivity analysis with the GC/MS-SIM mode. For isoBOC derivatization and TBDMS derivatization the recoveries were 92.3∼150.6% and 93.8∼108.3%, the method detection limits (MDLs) of bisphenol A for SIM were 0.062 $\mu$ g/kg and 0.010 $\mu$ g/kg, and the SIM responses were linear with the correlation coefficient varying by 0.9755∼0.9981 and 0.9908∼0.9996, respectively. When these methods were applied to mackerel samples, the concentrations of the 11 phenol EDCs were below the MDL.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.167-168
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• 2002

Because of the differences between biological and pharmacological properties of chiral drugs in human body, accurate determinations of their optical purities have been in great need. There are two major approaches in chiral separation: indirect method performed under achiral condition, and direct method under the chiral environment. We have been conducting chiral separation of acidic chiral compounds and also amino acidic chiral compounds employing indirect GC methods and direct CE enantiomeric separation methods. (omitted)

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.120.2-121
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• 2003

The alkylphenols, chlorophenols and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring (GC/MS-SIM) mode followed by two work-up methods for comparison; isoBOC derivatization method and TBDMS derivatization method. Eleven phenols in paper samples were extracted with acetonitrile. (omitted)

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 1997년도 가을 학술발표회 프로그램
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• pp.37-39
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• 1997

Pesticide residues were extracted with 70% acetone and transferred to dichloromethane. Extracts were applied to open-column chromatography with florisil and alumina-N, The final extract was analyzed by gas chromatography with electron-capture detector(GC/ECD) and nitrogen-phosphorus detector(GC/NPD). Recoveries of the 17 organochlorine pesticides were ranged from 60.8 to 84.9% and those of 15 organophosphorus pesticides, from 70.5 to 100.0%(except phosmet and azinphos-methyl). The minimum detectable levels of this analytical method were low (0.021-0.058 mg/kg).

• Bulletin of the Korean Chemical Society
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• 제19권11호
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• pp.1189-1193
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• 1998

The determination of total paraffin, naphthene, and aromatic (PNA) contents in naphtha samples, which were directly obtained from actual refining process, has been studied using near-infrared (NIR) spectroscopy. Each of the total PNA concentrations in naphtha has been successfully analyzed using NIR spectroscopy. Partial least squares (PLS) regression method has been utilized to quantify the total PNA contents in naphtha from the NIR spectral bands. The NIR calibration results showed an excellent correlation with those of conventional gas chromatography (GC). Due to its rapidity and accuracy, NIR spectroscopy is appeared as a new analytical technique which can be substituted for the conventional GC method for the quantitative analysis of petrochemical products including naphtha.