• Korean Journal of Food Science and Technology
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• v.23 no.2
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• pp.129-132
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• 1991

The volatile components of Perillae folium were isolated by simultaneous steam distillation-extraction method, and analyzed by combined GC and GC-MS. Among seventeen components indentified 6 alcohols (3-octanol, 1-octen-3-ol, linalool, nerolidol, supathuleol and phytol), 2 ketones, 1 aldehyde, 1 phenol and 7 hydrocarbons were confirmed. The most abundant component was myristicin comprising about 53.4%.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.10
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• pp.148-155
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• 1998

For products of various shapes, compound surfaces are used. Blending surfaces are essential to the products of the compound surfaces. In this paper a method of making shape of blending surface flexible with parameter control is discussed. The parameter has quantitative control of shape of the blend. The blending surface is applied to NURBS and simple primitives in solid model. Intersection curves of surfaces is used to provide the blend with generality. Rail curve are found with the intersection curves. The blend is generated by rail curves and parameter control. Also, In strict constraint condition, blending surface with flexible shapes is discussed, keeping ;${GC}^1$ and ;${GC}^2$ continuity between free-formed surfaces and solids. Joining blending ,bridge blending and blending surface at corner are generated.

• Analytical Science and Technology
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• v.16 no.6
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• pp.438-442
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• 2003

The fungicides, used for grape growth and remained in the wine products from domestic and foreign countries such as vinclozolin, dichlofluanid, penconazole, procymidone were quantitatively analyzed after solid-phase extraction using a GC/MS-SIM method. The results obtained were as follows: for all the samples, the content of procymidone was in the range from 2.2 to $76.1{\mu}g/L$, recoveries 81.3-93.1 %, and standard deviation 1.4-3.4 %.

• Journal of Food Hygiene and Safety
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• v.10 no.4
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• pp.239-247
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• 1995

Analytical method for saccharin in foods was developed using gas chromatography/mass spectrometry(GC/MS). Methylation with diazomethane, acetylation with MBTFA, and silylation with MSTFA and MTBSTFA were compared. Methylation of saccharin produced N-methylated saccharin as the major product and O-methylated saccharin as the minor one. Silylation of saccharin with MSTFA and MTBSTFA reasulted in the formation of the correponding O-silylated products, respectively. The derivatization of saccharin was optimized with MSTFA. The ions at m/z 240, 255, and 166 were monitored to characterize saccharin.

• The Korean Journal of Food And Nutrition
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• v.10 no.1
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• pp.1-5
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• 1997

The volatile components of Lycium chinensis Miller were isolated by simultaneous steam distillation-extraction(SDE) method and analyzed by combined GC and GC-MS. Fifty-four volatile components, including 12 alcolhols 12 esters, 7 aldehydes, 6 acids, 5 ydrocarbons, 8 ketones, 1 furan and 3 pyrazines were confirmed in the fruit of Lycium chinensis Miller. The major components were hexadecanoic acid ethyl ester, 1-octadecanone, tetrapyrazine, 2-furancarboxaldehyde and ethyl linoleate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.4
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• pp.563-567
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• 1998

Volatile flavor components of edible portion of leek(Allium tuberosum R.) were extracted by SDE(simultaneous steam distillation and extraction) method using the mixture of n-pentane and diethylether (1 : 1, v/v) as an extract solvent and analyzed by GC-FID and GC/MS. Identification of the volatile flavor components was mostly based on the RI of GC and mass spectrum of GC/MS. A total of sixty-five components from leek extract were classified as 28 sulfur-containing compounds, 12 aldehydes, 9 alcohols, 4 lactones and esters, 3 acids and hydrocarbons, and 2 miscellaneous compouds. The sulfur-containing compounds were predominant in leek extract. Dimethyl disulfide(19.47%) and dimethyl trisulfide(17.38%) were the main compounds and trans-1-propenyl methyl disulfide, trans-2-hexenal and methyl allyl disulfide were also detected large amounts in leek.

• Journal of Environmental Science International
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• v.12 no.10
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• pp.1117-1120
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• 2003

Pesticides were extracted from samples with 70% acetone and methylene chloride in order, and then cleaned up via open-column chromatography apparatus packed with florisil, and finally analyzed simultaneously the organophosphorus pesticides using GC/NPD. Ultra-2 and Ultra-1 fused silica capillary columns were used to separate and identify the products. Recovery of most analytes from soybean sample, taken from pesticide residues well, was greater than(80%) for all except(6) analytes. This method can simultaneously determine multiple pesticides with a high degree of accuracy and precision.

• Elastomers and Composites
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• v.54 no.3
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• pp.188-200
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• 2019

Rubber articles contain various organic additives such as antidegradants, curing agents, and processing aids. It is important to extract and analyze these organic additives. In this paper, various extraction methods of organic additives present in rubber composites were introduced (solvent extraction, Soxhlet extraction, headspace extraction, and solid-phase microextraction), and the extracts were characterized using gas chromatography/mass spectrometry (GC/MS). Solvent and Soxhlet extractions are easy-to-perform and commonly used methods. Efficiency of solvent extraction varies according to the type of solvent used and the extraction conditions. Soxhlet extraction requires a large volume of solvent. Headspace sampling is suitable for extracting volatile organic compounds, while solid-phase extraction is suitable for extracting specific chemicals. GC/MS is generally used for characterizing the extract of a rubber composite because most components of the extract are volatile and have low molecular weights. Identification methods of chemical structures of the components separated by GC column were also introduced.

• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.353-357
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• 2012

The new qualitative and quantitative analytical method for hydrocarbon compounds in DME-LPG blending fuel, mixing dimethyl ether (DME) with liquefied petroleum gas (LPG), by using gas chromatography (GC) was investigated. It is difficult to analyze all components of DME-LPG blending fuel by using single column in GC due to consisting of the non-polar LPG and the polar DME which is oxygen-containing compound. Therefore, it has been introduced the Deans switching system, which are useful for analyzing mixtures of a very different nature and/or target analytes in very complex matrix. This technique is to control the pressure between two columns and to selectively change the path of effluent flows to either one of two columns. As a result, we found that DME and LPG can be completely separated at the different columns and the determination of all hydrocarbon compounds in DME-LPG blending fuel can be achieved to this method qualitatively and quantitatively during the operation of one injection. In addition, this method can be applied to the determination of trace components of by-product, such as methanol, methyl formate and ethyl methyl ether, which will be derived from DME synthesis process.

• The Korean Journal of Pesticide Science
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• v.16 no.3
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• pp.242-256
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• 2012

QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method has been a lot of research for pesticide analysis, because it is very simple and fast. However, this method requires high sensitivity instrument such as LC-MS/MS because of the use of small sample volume and many impurities compared to the conventional method. So, QuEChERS method needs to be modified for using with HPLC and GC-ECD/NPD. The aim of this work was to study the application of the QuEChERS method as well as its modification for the extraction and preconcentration of 5 groups of 61 pesticides from 4 fruits prior to their determination by HPLC-PDA, GC-ECD/NPD, and LC-MS/MS. The method was validated using spiking levels at 0.1 mg/kg (or 0.01 mg/kg) in apple, grapes, pear and persimmon. The average recovery by QuEChERS AOAC Official 2007. 01 version using the LC-MS/MS varied from 71.1127.4% for 61 pesticides. The average recovery rates using modified QuEChERS varied from 70.9~126% for 61 pesticides by HPLC-PDA and GC-ECD/NPD. The results satisfied the criteria of multiple pesticide residue analysis, setting 70~130% for recovery rates and below 30% for CV.