• YAKHAK HOEJI
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• v.37 no.4
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• pp.356-361
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• 1993

A sensitive method for the determination of methamphetamine(MA) and amphetamine(AM) in hair was developed by gas chromatography/mass spectrometry using stable isotope-labeled internal standards, amphetamine-d$_{5}$ and methamphetamine-d$_{5}$. Hair sample was washed with MeOH, incubated with MeOH(I% HCI) overnight at $37^{\circ}C$ while stirring and extracted using solid phase extraction column on a vacuum manifold. The extract obtained was pentafluoropropionated, and applied to GC/MS. The calibration curves of MA and AM were linear from 2.5 to 250 ng (r>0.99 for both). The limit of detection was 0.1 ng/mg in hair and cut-off level was set at 0.25 ng/mg for both. Hair samples of 27 MA abusers showed positive results in the range 0.7 to 106.8 ng/mg. AM, its metabolite, was detected in 20 out of 27 samples. The ratio of MA versus AM was 4.6~38.3 in specimens. Hair analysis for methamphetamine by GC/MS is an effective method for identifying long-term drug abusers.

• Analytical Science and Technology
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• v.13 no.2
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• pp.136-150
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• 2000

For the identification of unknown drugs in biological samples, we attempted rapid high performance thin layer chromatographic method which is sensitive and selective chromatographic analysis of high performance thin layer chromatography (HPTLC) with automated TLC sampler and ultra-violet (UV) scanner. We constructed HPTLC database (DB) on two hundred five drugs by using the data of Rf values and UV spectra (scan 200-360 nm) as well as gas chromatography/mass spectrometry (GC/MS) DB on ninety six drugs by using the data of relative retention time (RRT) on lidocain and mass spectra. After extracting drugs in biological sample by solid phase extraction (Clean Screen ZSDAU020), we applied them to HPTLC and GC/MS DB. Drugs, especially extracted from biological samples, showed good matching ratio to HPTLC DB and these drugs were confirmed by GC/MS. In conclusion, this DB system is thought to be very useful method for the screening of unknown drugs in biological samples.

• Analytical Science and Technology
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• v.15 no.1
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• pp.26-30
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• 2002

In order to determine the contents of ethyl carbamate in Korean traditional alcoholic beverages and general beverages, GC/MS-SIM method was used after extraction of beverages with dichloromethane. The contents of ethyl carbamate in Korean traditional alcoholic beverages, non-distilled alcohol, and whisky were detected in the range of $4.6-50.2{\mu}g/L$, $27.8-45.4{\mu}g/L$, and $24.8-55.1{\mu}g/L$, respectively. The recoveries were ranged from 83.3 to 104.8 %. The values of relative standard deviation were ranged from 1.8 to 14.8 % and the detection limit was $0.3{\mu}g/L$.

• Analytical Science and Technology
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• v.14 no.6
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• pp.471-475
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• 2001

Solid phase microextraction(SPME) with $85{\mu}m$-polyacrylate (PA) and $100{\mu}m$-polydimethylsiloxane(PDMS) fibers, coupled to gas chromatography-mass spectrometry was used to determine 1,2-dibromo-3-chloropropane(DBCP) and n-butylbenzene in water. The conditions affecting the SPME process(i.e, extraction time, injection length, injection temperature, desorption time and temperature) were optimized. The linearity of the calibration curve (correlation coefficient, R) was over 0.99 and the limits of detection of the method were between 1.5 and $10.8{\mu}g/L$. Repeatability of the method was between 10.4 and 14.4 %.

• Korean Journal of Agricultural Science
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• v.36 no.2
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• pp.219-224
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• 2009

Two functional modified-butterfats (MF668 and MF866) were synthesized with two blends (6:6:8 and 8:6:6, w/w%) of anhydrous butterfat (ABF), palm stearin (PS) and flaxseed oil (FSO, omega-3) via lipase-catalyzed interesterification reaction. Their flavor characteristic was investigated using electronic nose and SPME-GC/MS analysis. Each flavor pattern of ABF, FSO, MF668 and MF866 was significantly discriminated with first principal component score of 95.16% in PCA plot. In functional modified-butterfats analyzed with SPME-GC/MS, various volatile compounds such as aldehydes, ketones, acids, and alkanes were detected.

• Mass Spectrometry Letters
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• v.3 no.1
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• pp.15-17
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• 2012

Eighteen of the PDE-5 inhibitors and their analogues were analyzed using GC-EI-MS. Fourteen of them could be identified by simple GC-MS method without derivatization, but hydroxyhongdenafil, hydroxyvardenafil, xanthoanthrafil and mirodenafil could not be identified without derivatization for the high polarity due to the presence of hydroxyl groups. N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA) and N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA), widely used trimethylsilyl (TMS) derivatizing reagents, were used to improve the sensitivity of the hydroxylated analogues. And the analytes could be identified by GC-MS after the derivatization.

• Journal of the Korean Wood Science and Technology
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• v.23 no.2
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• pp.19-25
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• 1995

This research was carried out to investigate the methods of liquefaction with Pinus koraiensis, and chemical components of the liquefied wood by FT-IR analysis and pyrolysis-GC/MS. Acetylated wood powder was liquefied above 90% in phenol or m-cresol when treated at about 150$^{\circ}C$ for 30min., using some catalysts. Untreated wood powder was liquefied above 90% in phenol or m-cresol when treated at about 200$^{\circ}C$ for 60min., using some catalysts. The results of FTIR analysis, carbohydrates were terribly disintegrated, the other side lignin peaks were occurred in liquefied wood, particulary. The results of pyrolysis-GC/MS, the liquefied wood have clear four peaks, phenol, guaiacol, o-cresol and m-/p-cresol, due to degradation of lignin, particulary.

• Analytical Science and Technology
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• v.8 no.4
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• pp.829-834
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• 1995

Whole column coldtrapping(WCC) on a fused silica capillary (FSCC)combined with GC/MS analysis was evaluated for use in the investigation of volatile organic compounds(VOCs) in indoor air. Research had indicated that a temperature of $-80^{\circ}C$ is optimal for WCC. Samples were analyzed on a $50m{\times}0.2mm$ cross-linked 5% phenylmethylsilicone fused silica column. Liquid nitrogen was used as the coolant for the peak resolution significantly. The analysis can be performed quickly and conveniently. More than 112 of VOCs were determined in the samples from three typical indoor environment including: (1) a room which had just been decorated involving building materials and paints; (2)a kitchen used for Chinese cooking, and (3) a room had tobacco smoke. The method is could be readily applied to rapid sample screening for VOCs contamination surveys or initial investigations with its valid and simple sampling and analytical technique.

• Analytical Science and Technology
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• v.37 no.1
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• pp.1-11
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• 2024

In agricultural households cultivating vegetables and fruits, the use of various pesticides to protect crops from diseases and pests or to control weeds is widely practiced enhancing quality and productivity. However, pesticides can pose a threat to consumer health by remaining on the food surface or migrating into the food interior. Households commonly peel off skins, wash with water, or use chemical methods to remove foreign substances including residual pesticides on the food surface. In this study, we measured the washing rate by comparing the pesticide concentrations before and after washing in the leafy vegetable perilla leaves and the fruits strawberries and apples, which were intentionally exposed to pesticides. We compared washing rates using tap water, a baking soda solution, and a commercially available food-specific cleaning solution. The target pesticides for analysis were azoxystrobin, bifenthrin, boscalid, difenoconazole, flubendiamide, and indoxacarb, and the residual pesticide analysis was performed using GC-MS/MS or LC-MS/MS. The removal rates of pesticides were highest with the food-specific cleaner, followed by baking soda and tap water in order.

• Journal of Conservation Science
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• v.37 no.6
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• pp.638-647
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• 2021

Organic residues are substances derived from diverse natural sources. Recent scientific analysis of organic residues has yielded important information in restoring the lifestyles of ancient peoples. In this study, the organic material contained within the celadon oil bottle of the Goryeo dynasty, excavated from the Soejoul site in Geumneung-dong, Chungju, was analyzed using Fourier-transform infrared spectroscopy (FT-IR) and gas chromatograph-mass spectrometer (GC-MS). The results showed that the organic materials in the bottle were plant-derived oils. In particular, polyunsaturated fatty acids and phytosterols were detected using GC-MS analysis. Sesamin components were also identified. Sesamin, which is a characteristic component of sesame seeds, is a lignan and an antioxidant. As the organic residues in the oil bottle were derived from sesame seeds, it is presumed that sesame oil was stored in the bottle.