• Journal of Food Hygiene and Safety
• /
• v.14 no.2
• /
• pp.140-145
• /
• 1999

Analytical method for preservatives in food was developed using gas chromatography/mass spectrometry (GC/MS). Propionic acid, sorbic acid, benzoic acid, ethyl salicylate, ethyl p-hydroxy benzoate, iso-propyl p-hydroxy benzoate, n-propyl p-hydroxy benzoate, iso-butyl p-hydroxy benzoate, n-butyl p-hydroxy benzoate, p-hydroxy benzoic acid and dehydro acetic acid were extracted from cooling beverage with diethyl ether. The polar hydroxyl and carboxyl groups of food preservatives were derivatized with N-methyl-N-tert-butyldimethylisilyl-trifluoroscetamide (MTBSTFA) to form the corresponding tert-bytyldimethyl-silylated derivatives, and submitted to GC/MS analysis. The mass spectra of the derivatives were investigated for the selection of monitoring ions for multi-residue analysis of 11 preservatives by GC/MS. The macro program was also developed for the qualitative analysis of these preservatives in food.

• YAKHAK HOEJI
• /
• v.26 no.2
• /
• pp.129-132
• /
• 1982

A GC/MS method was developed to analyze phenolic acid extract from tobacco leaf. Extracted acids were converted to their methyl esters by refluxing with 3M hydrogen chloride in methanol, and the esters were reacted with his (trimethylsilyl) trifluoroacetamide plus 10% trimethylchlorosilane to silylate the phenolic groups. Derivatives of standard salicylic, p-hydroxybenzoic, vanillic, gentisic, p-coumaric, syringic, ferulic, and sinapic acids prepared by this procedure were analyzed by GC/MS on $20m{\times}0.2mm$ column of SE-54 glass capillary. GC/MS analysis of the extract from tobacco leaf revealed the presence of salicylic, p-hydtoxybenzoic, vanillic, gentisic, protocatechuic, p-coumaric, syringic, gallic, ferulic, caffeic, sinapic, and quinic acids, respectively. The quantitative analysis of these phenolic acids were achieved by using multiple ion selection technique.

• Journal of Ginseng Research
• /
• v.20 no.3
• /
• pp.284-290
• /
• 1996

To Identify phenolic components known to exist in Korean ginseng (Panax ginseng C.A. Meyer) by GC/MS, three derivatization methods were employed for their analyses. First, phenolic components in ether soluble acidic fraction prepared from Korean red ginseng powder were taimethylsilylated. Secondly, phenolic acids in the same fraction were esterified with diazomethane followed by trlmethylsilylation. Thirdly, acidic components in ginseng powder were extracted and esterified concurrently by methanolic sulfuric acid, followed by fractionation of phenolic components with Silica Sep-Paka and trimethylsilylatlon. All phenolic components found in ginseng except gen tisic acid were identified by retention times and mass spectrums of standards. Besides, 5 phenolic components including salicyl alcohol and 1-H-indole-2-carboxylic acid were first identified from Korea an red ginseng by GC/MS.

• Archives of Pharmacal Research
• /
• v.4 no.2
• /
• pp.85-90
• /
• 1981

A quantitative GC-MS spectrometric assay was used for the determination of residual N, N-dimethylaniline as a contaminant in commercial penicillin derivatives from various sources. The assay utilizes selective ion focusing to monitor in a GC effluent the molecular ions of DMA generated by electron impact ionization. This method includes dissolution of the sample in alkaline solution, extraction of organic base with cyclohexane and injection into GC-MS with a 3% OV-17 column. Levels of 50 ppb of DMA were easily measured with a coeffecient of varation less than 5 % and recoveries from spiked samples exceeded 97 %. The results of the determinations of DMA in various commercial penicillins were relatively free of this contaminant.

• Journal of Gastric Cancer
• /
• v.22 no.4
• /
• pp.348-368
• /
• 2022

Purpose: Chromosomal instability is a hallmark of gastric cancer (GC). It can be driven by single nucleotide variants (SNVs) in cell cycle genes. We investigated the associations between SNVs in candidate genes, PLK2, PLK3, and ATM, and GC risk and clinicopathological features. Materials and Methods: The genotyping study included 542 patients with GC and healthy controls. Generalized linear models were used for the risk and clinicopathological association analyses. Survival analysis was performed using the Kaplan-Meier method. The binding of candidate miRs was analyzed using a luciferase reporter assay. Results: The PLK2 C_rs15009-C_rs963615 haplotype was under-represented in the GC group compared to that in the control group (P_corr=0.050). Male patients with the PLK2 rs963615 CT genotype had a lower risk of GC, whereas female patients had a higher risk (P=0.023; P=0.026). The PLK2 rs963615 CT genotype was associated with the absence of vascular invasion (P=0.012). The PLK3 rs12404160 AA genotype was associated with a higher risk of GC in the male population (P=0.015). The ATM T_rs228589-A_rs189037-G_rs4585 haplotype was associated with a higher risk of GC (P<0.001). The ATM rs228589, rs189037, and rs4585 genotypes TA+AA, AG+GG, and TG+GG were associated with the absence of perineural invasion (P=0.034). In vitro analysis showed that the cancer-associated miR-23b-5p mimic specifically bound to the PLK2 rs15009 G allele (P=0.0097). Moreover, low miR-23b expression predicted longer 10-year survival (P=0.0066) in patients with GC. Conclusions: PLK2, PLK3, and ATM SNVs could potentially be helpful for the prediction of GC risk and clinicopathological features. PLK2 rs15009 affects the binding of miR-23b-5p. MiR-23b-5p expression status could serve as a prognostic marker for survival in patients with GC.

• Korean Journal of Pharmacognosy
• /
• v.51 no.3
• /
• pp.207-216
• /
• 2020

The analysis method for qualitative analysis of the screening method that can be performed prior to the quantitative analysis of individual pesticide was reviewed in order to meet the safety standards that are being strengthened in the field of pesticide residue testing of herbal medicines. Among the residual pesticides presented in the Korean Pharmacopoeia, 56 pesticides, excluding 15 pesticides that need to be individually analyzed, were selected for analysis using QuEChERS preprocessing and GC-MS/MS, which are used in the existing agricultural products field. For each pesticide, the detection limit level of 0.001-0.005 mg/kg and the quantitative limit level of 0.002-0.017 mg/kg were confirmed. In the recovery test in which the standard was treated at a concentration of 0.02 mg/kg, it was confirmed that the proportion of pesticides satisfying the recovery of 70-120% was 85.7-96.4% for each herbal medicine, so it was confirmed that it was a level that could be reviewed by the screening method.

• Analytical Science and Technology
• /
• v.8 no.3
• /
• pp.237-248
• /
• 1995

The simultaneous analysis of 16 organic pesticides, which are listed as a part of 129 priority pollutants by EPA(Environmental Protection Agency), was performed by GC-ECD(electron capture detector) and GC/MS-SIM(selected ion monitoring). Two extraction procedures from SW-846, sonication extraction and Soxhlet extraction, were somewhat modified and compared as an extraction and concentration method for the analysis of priority pollutants in soil. Accuracy and precision of the methods were reported from the calculation of mean recovery, mean relative standard deviation, and method detection limit.

• Journal of the Society of Naval Architects of Korea
• /
• v.31 no.4
• /
• pp.32-40
• /
• 1994

This paper describes a smooth surface interpolating method of ship hull using a three-dimensional currie net that comes from the mesh curve fairing process. Geometric continuity(($GC^1$) is preserved across the boundary curve between patches. The three-dimensional curve net can have nonrectangular topologies, such as triangular and pentagonal topology. Among the boundary curve interpolation methods, Hermite blended Coons patch, Convex combination, and Gregory patch interpolation method are used to generate the ship hull surface. To check the fairness of the surface, the numerical method of surface/surface intersection problem is adopted. An application to an actual ship hull is given as an example.

• Proceedings of KOSOMES biannual meeting
• /
• 2006.05a
• /
• pp.85-92
• /
• 2006

Crude oil is complex mixture if thousands of different organic compound formed from a variety of organic materials that are chemically converted under differing geological conditions over long periods of time. Also oil composition varies according to crude source, refining, processing, handling and storage. The oil fingerprint method is application if specific knowledge of petrochemicals and use if sophisticated analytical equipment and techniques to identify the source(s) if oil pollution. KCG currently utilizes four primary analytical techniques: Gas Chromatography (GC), Fluorescence Spectroscopy(FL), Infrared Spectroscopy(IR) and Gas Chromatography mass spectrometer(GC/MS). Of all these techniques, GC technique are most widely used Gas Chromatography is used as a primary analytical method because high reliableness, high separating efficiency and repeatability.

• Proceedings of KOSOMES biannual meeting
• /
• 2006.11a
• /
• pp.169-174
• /
• 2006

A distinctive difference of hydrocarbon in crude oil and petroleum products exists. Depending on the origin where it comes from, crude oil shows its own unique pattern which is different from petroleum products containing characteristics according to their operating process and production period. A process of mixing behavior in a tank containing residual amounts of oil draws its own pattern when analysis is conducted. The analytical process described above is named oil fingerprint method. This study investigates an effectiveness of the method for comparing data sets produced by conventional gas chromatography with mass spectrometer (GC/MS) and comprehensive two-dimensional gas chromatography (GC X GC) which is known as powerful new technology for chemical analysis.