• Analytical Science and Technology
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• v.6 no.3
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• pp.335-343
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• 1993

The structure of cerebrosides from soybean embryo was determined using fast atom bombardment mass spectrometer (FAB-MS), gas chromatography mass spectrometer (GC-MS) and TLC. The components of cerebroside were determined by GC-MS after acid hydrolysis. The molecular weight distribution of cerebroside was measured by positive mode FAB-MS with LiOH saturated 3-nitrobenzylalcohol(3-NBA) matrix. Structures of individual components of complex mixtures can be determined easily by this process. The major constituent of soybean extracted cerebroside was determined as the glucoside of N-2'-hydroxypalmitoyl-sphingadienine.

• Journal of the Korean Society of Tobacco Science
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• v.36 no.1
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• pp.26-33
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• 2014

Simultaneous determination of crop protection agents(CPAs) in food are done with multi-residue methods, which are composed of sample clean-up, concentration, chromatographic separation and detection. Stir Bar Sorptive Extraction(SBSE) technique is used for sample preparation of various analytes in several fields. The aim of this study was to develop a sensitive and fast method based on SBSE followed by thermal desorption - gas chromatography - mass spectrometry(TD - GC/MS) to determine CPAs in tobacco sample. For the analysis of tobacco sample prior to the SBSE method, solvent extraction or ultrasound-assisted solvent extraction was performed. methanol was used as the extraction solvent. The extract was then diluted with water. Finally, the sample was subjected to SBSE. A method for fast screening of crop protection agents in tobacco using SBSE-TD - GC/MS has been developed. About 17 CPAs including organochlorine, organophosphorous and others were identified and quantified. This method showed good linearity and high sensitivity for most of the target CPAs. The method was applied to the determination of CPAs at ng/mL levels in tobacco sample. This method is simple, rapid and may be applied in detection of other components.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3123-3127
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• 2010

A highly sensitive electrochemical detection method for dopamine (DA) has been developed by relying on a multiwalled carbon nanotube (CNT)-sol-gel titania-Nafion composite film modified glassy carbon (GC) electrode. The CNT-titania-Nafion/GC electrode exhibited excellent electrocatalytic activity towards DA. Therefore, the CNT-titania-Nafion/GC electrode showed improved voltammetric and amperometric responses for DA compared to those obtained with both titania-Nafion/GC and Nafion/GC electrodes. The CNT-titania-Nafion/GC electrode gave a linear response ($R^2$ = 0.999) for DA from $0.5\;{\mu}M$ to 0.5 mM with a detection limit (S/N = 3) of $0.1\;{\mu}M$ and a good sensitivity of 150 mA/M while other electrodes such as CNT-Nafion/GC, titania-Nafion/GC, and a bare GC gave a sensitivity of 89, 39, and 36 mA/M, respectively. Besides, the CNT-titania-Nafion/GC electrode displayed very fast response time within 2 s. The modified electrode showed good selectivity against ascorbic acid. The modified electrode showed good stability and reproducibility. The CNT-titania-Nafion/GC electrode was applied to the determination of DA in urine and serum samples.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.3
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• pp.122-130
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• 2004

Crude oil is complex mixture of 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 of specific knowledge of petrochemicals and use of sophisticated analytical equipment and techniques to identify the source(s) of oil pollution. KNMPA currently utilizes three primary analytical techniques: Gas Chromatography (GC), Fluorescence Spectroscopy(FL) and Infrared Spectroscopy(IR). 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, but it is timeconsumable. The study results of identification of waterborne spilled oil by Fast Gas Chromatograph method showed that analytical time is cut down to 30minutes in comparison with packed column method and chromatograms represent high resolution and high repeatability.

• Journal of the Korean Society of Tobacco Science
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• v.29 no.2
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• pp.132-139
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• 2007

This study was performed to apply the more rapid and accurate sample preparation, and the high selectivity and sensitivity of the analyte detection by gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS). QuEChERS (quick, easy, cheap, effective, rugged and safe) method was validated for 49 agrochemicals in the CORESTA Agrochemical Advisory Committee guide and amenable to GC-MS/MS determination. In QuEChERS method, the effects of sorbents (PSA, $C_{18}$ and GCB) and matrix of the analytes in tobacco types (flue-cured, burley and oriental) were investigated. MS/MS acquisition provided high specificity and selectivity for agrochemicals and low limit of quantification. QuEChERS by using PSA alone and the matrix-matched standards gave good recoveries and RSD values in three types of tobaccos. QuEChERS method was no needed to be complex clean-up procedure and would be used as the fast and easy method for agrochemical residue analysis in tobacco.

• Food Science of Animal Resources
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• v.41 no.5
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• pp.816-825
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• 2021

This study aims to validate a fast method of simultaneous analysis of 365 LCamenable and 142 GC-amenable pesticides in hen eggs by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS), respectively, operating in multiple reaction monitoring (MRM) acquisition modes. The sample preparation was based on quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction. Key method performance parameters investigated were specificity, linearity, limit of quantification (LOQ), accuracy, precision and measurement uncertainty. The method was validated at two spiking levels (10 and 50 ㎍/kg), and good recoveries (70%-120%) and relative standard deviations (RSDs) (≤20) were achieved for 92.9% of LC-amenable and 86.6% of GC-amenable pesticide residues. The LOQs were ≤10 ㎍/kg for 94.2% of LC-amenable and 92.3% of GC-amenable pesticides. The validated method was further applied to 100 egg samples from caged hens, and none of the pesticides was quantified.

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.278-295
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• 2014

Fast and accurate multi-residue pesticides inspecting method needs in Agro-Fishery Products Inspection Center. So, We tried to seek the optimum method using GC-TOF/MS, GC-ECD, GC-NPD after QuEChERS sample preparation. In GC-TOF/MS, 138 kinds of pesticide were spiked at 0.3 and $0.5{\mu}g/g$for the identification and quantification in lettuce sample. Recoveries of 77 pesticides were between 70 and 130% with RSD (relative standard deviation lower than 20% at $0.3{\mu}g/g$. In GC-ECD, NPD, 146 kinds of pesticide were spiked for the identification and quantification in lettuce. Recoveries of 61 species were between 70 and 130% with lower than 20%. These results indicated that GC-TOF/MS, GC-ECD, NPD analysis with the QuEChERS sample preparation can be partly applied to multi-residue pesticides in vegetables.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1703-1707
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• 2013

A fast and simple sampling and sample preparation device, (NTD) has been developed and applied to sample and analyze volatile components from ground coffee beans. Coffee fragrances and other volatile organic compounds (VOCs) were sampled by the NTD and then analyzed by gas chromatograph-mass spectrometry (GC/MS). Divinylbenzene (DVB) particles (80/100 mesh size) were the sorbent bed of the NTD. More than 150 volatile components were first identified based on the database of the mass library and then finally 30 fragrances including caffeine were further confirmed by comparing experimental retention indices (i.e. Kovat index) with literature retention indices. Total sampling time was 10 minutes and no extra solvent extraction and/or reconstitution step need. Straight n-alkanes (C6-C20) were used as retention index probes for the calculation of experimental retention indices. In addition, this report suggests that an empty needle can be an alternative platform for analyzing polymers by pyrolysis-GC/MS.

• Journal of Applied Biological Chemistry
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• v.63 no.1
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• pp.29-33
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• 2020

The objective of this study was to develop a fast and accurate method of variety discrimination and geographical discrimination origin of Korean angelica (Korean variety, Angelica gigas Nakai) by using TDU-GC/MS. Two peaks of decursin and decursinol, which are coumarin derivatives were identified in the range of Total Ion Chromatogram (TIC) RT 26.9-27.2 of the Korean angelica by GC/MS analysis at the time of condensation in a refrigerated condensation system after thermal desorption of sample extracts. In case of Chinese angelica (Chinese variety), ligustilide peak was detected at the RT 17.2. In order to investigate the difference of volatile components according to the geographical origin of Korean variety, the mass spectra were measured by TDU-GC/MS at the range of m/z 40-400 amu. The TIC of domestic cultivation and Chinese cultivation of the Korean variety, Angelica gigas Nakai showed the same tendency as a whole. However, in partial scans of TIC, two peaks detected at 15.54 and 16.05 of RT showed different peak patterns between Korean angelica (Korean variety) cultivated in Korea and in China. The ratio of Peak A (RT 15.54) and B (RT 16.05) was 0.0-0.2 for domestic cultivation and 0.5-2.8 for Chinese cultivation, confirming the possibility of discriminating origin by comparing the TIC peak pattern of TDU-GC/MS.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.283-291
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• 2006

To investigate seed non destructive and fast determination technique utilizing near infrared reflectance spectroscopy (NIRs) for screening ultra high oleic (C18:1) and linoleic (C18:2) fatty acid content sesame varieties among genetic resources and lines of pedigree generations of cross and mutation breeding were carried out in National Institute of Crop Science (NICS). 150 among 378 landraces and introduced cultivars were released to analyse fatty acids by NIRs and gas chromatography (GC). Average content of each fatty acid was 9.64% in palmitic acid (C16:0), 4.73% in stearic acid (C18:0), 42.26% in oleic acid and 43.38% in linoleic acid by GC. The content range of each fatty acid was from 7.29 to 12.27% in palmitic, 6.49% from 2.39 to 8.88% in stearic, 12.59% of wider range compared to that of stearic and palmitic from 37.36 to 49.95% in oleic and of the widest from 30.60 to 47.40% in linoleic acid. Spectrums analyzed by NIRs were distributed from 400 to 2,500 nm wavelengths and varietal distribution of fatty acids were appeared as regular distribution. Varietal differences of oleic acid content good for food processing and human health by NIRs was 14.08% of which 1.49% wider range than that of GC from 38.31 to 52.39%. Varietal differences of linoleic acid content by NIRs was 16.41% of which 0.39% narrower range than that of GC from 30.60 to 47.01%. Varietal differences of oleic and linoleic acid content in NIRs analysis were appeared relatively similar inclination compared with those of GC. Partial least square regression (PLSR) among multiple variant regression (MVR) in NIRs calibration statistics was carried out in spectrum characteristics on the wavelength from 700 to 2,500 nm with oleic and linoleic acids. Correlation coefficient of root square (RSQ) in oleic acid content was 0.724 of which 72.4 percent of sample varieties among all distributed in the range of 0.570 percent of standard error when calibrated (SEC) which were considerably acceptable in statistic confidence significantly for analysis between NIRs and GC. Standard error of cross validation (SECV) of oleic acid was 0.725 of which distributed in the range of 0.725 percent standard error among the samples of mother population between analyzed value by NIRs analysis and analyzed value by GC. RSQ of linoleic acid content was 0.735 of which 73.5 percent of sample varieties among all distributed in the range of 0.643 percent of SEC. SECV of linoleic acid was 0.711 of which distributed in the range of 0.711 percent standard error among the samples of mother population between NIRs analysis and GC analysis. Consequently, adoption NIR analysis for fatty acids of oleic and linoleic instead that of GC was recognized statistically significant between NIRs and GC analysis through not only majority of samples distributed in the range of negligible SEC but also SECV. For enlarging and increasing statistic significance of NIRs analysis, wider range of fatty acids contented sesame germplasm should be kept on releasing additionally for increasing correlation coefficient of RSQ and reducing SEC and SECV in the future.