• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2003.11a
• /
• pp.113-118
• /
• 2003

An investigation has been carried out on collision-induced dissociation (CID) in the development of an analytical protocol for the determination of polycyclic aromatic hydrocarbons (PARs) by ion trap tandem mass spectrometry. Two different considerations were used to choose the optimal CID conditions for complex matrix environmental samples, namely, to determine the highest signal-to-noise (SIN) ratio and the other to eliminate the background interferences originated from complex matrix samples. The PAR content of agricultural soil was measured to estimate overall distribution of PAR in throughout the country, we collected and analyzed 226 soil samples from paddy and upland soil. The average content of total PAR in all samples was 236 ${\mu}g$ $kg^{-1}$, and the range was from 23.3 to 2, 834 ${\mu}g$ $kg^{-1}$. The overall distribution of PAR was found to be closely related to the pollution sources, the size of city and the type of industry.

• Korean journal of food and cookery science
• /
• v.14 no.5
• /
• pp.541-546
• /
• 1998

Volatile flavor components in leaf and petiole of fresh Pleurospermum kamtschaticum H$\_$OFFM/ were extracted by SDE (simultaneous steam distillation and extraction) method using diethyl ether as solvent. Essential oils were analyzed by gas chromatography (GC) and combined gas chromatography-mass spectrometry (GC-MS). Identification of volatile flavor components was based on the Rl of GC and mass spectrum of GC-MS. A total of 31 components, including 15 hydrocarbons, 4 aldehydes, 1 ketone, 5 alcohols, 2 esters, 3 acids and 1 oxide were identified in the essential oils. (Z)-${\beta}$-Farnesene, (Z, E)-${\alpha}$-farnesene and farnesene were the major volatile flavor components in fresh Pleurospermum kamtschaticum. Volatile flavor patterns of Pleurospermum kamtschaticum were analyzed using electronic nose. Sensor T30/1 and PA2 that were sensitive to alcohols had the highest resistance for fresh Pleurospermum kamtschaticum. Resistance of six metal oxide sensors was decreased in dried sample compared with fresh one.

• Journal of the Korean Society of Tobacco Science
• /
• v.30 no.2
• /
• pp.117-124
• /
• 2008

A solid phase microextraction (SPME) method in combination with gas chromatography/mass spectrometric techniques was used for the extraction and quantification of 12 selected agrochemical residues in tobacco. The parameters such as the type of SPME fiber, adsorption/desorption time and the extraction temperature affecting the precision and accuracy of the SPME method were investigated and optimized. Among three types of fibers investigated, polyacrylate (PA), polydimethylsiloxane (PDMS) and polydimethylsiloxane-divinylbenzene (PDMS-DVB), PDMS fiber was selected for the extractions of the agrochemicals. The SPME device was automated and on-line coupled to a gas chromatograph with a mass spectrometer. Mass spectrometry (MS) was used and two different instruments, a quadrupole MS and triple quadrupole MS-MS mode, were compared. The performances of the two GC-MS instruments were comparable in terms of linearity (in the range of 0.01$\sim$0.5 $\mu$g/mL) and sensitivity (limits of detection were in the low ng/mL range). The triple quadrupole MS-MS instrument gave better precision than that of quadrupole MS system, but generally the relative standard deviations for replicates were acceptable for both instruments (< 15%). The LODs was fully satisfied the requirements of the CORESTA GRL. Recoveries of 12 selected agrochemicals in tobacco yielded more than 80% and reproducibility was found to be better than 10% RSD so that SPME procedure could be applied to the quantitative analysis of agrochemical residues in tobacco.

• Korean Journal of Food Science and Technology
• /
• v.47 no.5
• /
• pp.567-573
• /
• 2015

In this study, volatile compounds in nine commercial Japanese distilled liquors (Shochu) were isolated by headspace solid-phase microexrraction (SPME) and analyzed by gas chromatography (GC) and GC-mass spectrometry (MS). A total of 76 volatile components, including 48 esters, 13 alcohols, and 15 miscellaneous components, were identified. Esters and alcohols constituted the largest groups of quantified volatiles. Differences in volatile components among the distilled liquors and possible sample grouping were examined by applying principal component analyses to the GC-MS data sets. The first and second principal components explained 77.92% of the total variation across the samples. The samples using barley koji showed higher overall concentrations of total volatile components. Additionally, the principal component analysis did not reveal any sample grouping based on the raw material used.

• Food Science and Industry
• /
• v.55 no.1
• /
• pp.45-57
• /
• 2022

This study was proceeded the analytical methods using various analytical instruments for polycyclic aromatic hydrocarbons (PAHs) in food products. Various analytical methods were developed to determine levels of PAHs including benzo[a]pyrene, benzo[a]anthracene, benzo[b]fluoranthene, and chrysene formed in various food products using gas chromatography-mass spectrometry (GC-MS), enzyme-linked immunosorbent assay (ELISA) and raman spectroscopy. Recently, the rapid on-site response for the detection of hazardous substances in food aims to develop an onsite rapid detection of a simplified technical analysis method to reduce the time and cost required for analysis of PAHs. Current PAHs detection methods have been reviewed along with new raman spectroscopy analytical method.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.46 no.4
• /
• pp.309-316
• /
• 2001

Helianthus tuberosus has been known to inhibit the growth of weeds and other plants sharing its habitat. This study was conducted to identify the allelochemicals of Helianthus tuberosus which were extracted with water and solvents. Aqueous extracts of leaf, stem, root, tuber and tuber peel of Helianthus tuberosus except tuber did not show significant differences in phytotoxicity to alfalfa seedlings. It was considered that Helianthus tuberosus contained fewer or less potential water-soluble substances that were toxic to alfalfa. Methanol extract of leaves of Helianthus tuberosus was sequentially partitioned in increasing polarity with n-hexane, ethylacetate and n-butanol. Each extract had a yield of 148, 12, 15.7 and 9.5g, respectively. Inhibitory effects on germination of alfalfa seeds treated with four fractions were not significantly different. But the significant reductions on hypocotyl length were observed for all the solvent extracts. Among the four fractions, the ethylacetate fraction showed the most significant inhibition effect on bioassay with alfalfa. Further separation of the active ethylacetate fraction by open column chromatography led to the 25 subfractions. In bioassay of each sub-fraction with alfalfa seeds, sub-fraction No. 13 showed the most inhibitory effect on seedling growth. $^1$H NMR and gas chromatography-mass spectrometry analysis revealed that sub-fraction No. 13 was the mixture of straight-chain saturated fatty acids.

• Journal of Food Hygiene and Safety
• /
• v.39 no.2
• /
• pp.152-162
• /
• 2024

In this study, we investigated the levels of the natural preservatives, benzoic acid, sorbic acid, and propionic acid, in raw unprocessed vegetables. Quantitative analysis of benzoic acid and sorbic acid was performed using high-performance liquid chromatography with a diode array detector (HPLC-DAD) and confirmed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Propionic acid was analyzed using a gas chromatography-flame ionization detector (GC-FID) and confirmed using gas chromatography-mass spectrometry (GC-MS). From a total of 497 samples, benzoic acid, sorbic acid, and propionic acid were found in 50 (10%), 8 (0.2%), and 61 samples (12.3%), respectively. The highest quantity of benzoic acid, sorbic acid, and propionic acid was found in peony root (1,057 mg/kg), nut-bearing torreya seeds (27.3 mg/kg), and myrrha (175 mg/kg), respectively. The background concentration range of naturally occurring preservatives in raw vegetables determined in this study could be used as standard inspection criteria to address consumer complaints and trade disputes.

• Analytical Science and Technology
• /
• v.8 no.4
• /
• pp.821-827
• /
• 1995

Polychlorodibenzo-p-dioxins(PCDDs) have been prepared by microsacale pyrolysis of trichlorophenates. During the pyrolysis reaction, dechlorinated dibenzo-p-dioxins were also formed by the thermolysis of PCDDs. The dechlorination pathways of PCDDs were suggested in this reaction. The identification of these products was performed using capillary column gas chromatography-mass spectrometry.

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

• Elastomers and Composites
• /
• v.55 no.1
• /
• pp.6-12
• /
• 2020

Poly(ethylene-co-vinyl acetate) compounds and vulcanizates containing dicumyl peroxide (DCP) (HD) were prepared, and the curing agent and reaction products were analyzed using gas chromatography/mass spectrometry (GC/MS). Samples containing trially cyanurate (TAC) and DCP (HDT) were also prepared and analyzed. Some raw DCP were decomposed in the injector region of GC to produce acetophenone. DCP was detected in the HD compound but was not observed in the HD vulcanizate, and instead acetophenone and 2-phenyl-2-propanol were detected. Both DCP and TAC were observed in the HDT compound but not in the HDT vulcanizate, where acetophenone and 2-phenyl-2-propanol were detected. Thus, some of the DCP decomposed during the compounding process. The formation mechanism for acetophenone and 2-phenyl-2-propanol during the crosslinking reaction was identified, and differences in the crosslinking reactions of HD and HDT compounds were discussed.