• Korean Journal of Environmental Agriculture
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• v.34 no.4
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• pp.309-317
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• 2015

BACKGROUND: An analytical method was developed using GC-ECD/MS to precisely determine the residue of fipronil, a phenylpyrazole insecticide used to control a wide range of foliar and soil-borne pests.METHOD AND RESULTS: Fipronil residue was extracted with acetone from representative samples of five raw products which comprised hulled rice, soybean, Kimchi cabbage, green pepper, and apple. The extract was diluted with saline water, and fipronil was partitioned into n-hexane/dichloromethane (20/80, v/v) to remove polar co-extractives in the aqueous phase. Florisil column chromatography was additionally employed for final purification of the extract. Fipronil was separated and quantitated by GC-ECD using a DB-17 capillary column. Accuracy of the proposed method was validated by the recovery from crop samples fortified with fipronil at 3 levels per crop in each triplication.CONCLUSION: Mean recoveries ranged from 86.6% to 106.0% in five representative agricultural commodities. The coefficients of variation were less than 10%. Limit of quantitation of fipronil was 0.004 mg/kg as verified by the recovery experiment. A confirmatory technique using GC/MS with selected-ion monitoring was also provided to clearly identify the suspected residue. Therefore, this analytical method was reproducible and sensitive enough to determine the residue of fipronil in agricultural commodities.

• Natural Product Sciences
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• v.21 no.2
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• pp.87-92
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• 2015

The stem barks, heartwoods, and leaves of Acer tegmentosum (Aceraceae) are widely used in Korea to treat hepatic or cerebral disorders mainly due to alcohol poisoning. This study was aimed to analyze phenolic substances in A. tegmentosum. Quantitative analysis of the three phenolic substances (salidroside, (+)-catechin and scopoletin) was performed by HPLC and the identification of volatile phenolic substances were done by GC-MS. The contents of the three compounds in the three MeOH extracts were higher in the stem bark (salidroside: 80.22 mg/g, (+)-catechin: 23.31 mg/g, and scopoletin: 9.45 mg/g) compared to the heartwoods and leaves. And GC-MS analysis of the stem bark extract demonstrated that p-tyrosol is a main substance of twenty-one compounds identified.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.2
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• pp.127-137
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• 2002

Phenolic compounds in air are toxic even at their low concentrations. We had evaluated a total of five phenolic compounds (Phenol, o-Cresol, m-Cresol, 2-Nitrophenol and 4-Chloro-3-methylphenol) in artificial air using a combination of ATD/GC/MS. To compare the adsorption efficiency of these phenolic compounds, three adsorbents (Tenax TA, Carbotrap and Carbopack B) were tested. Tenax TA adsorbent was most effective of all the adsorbents used for the efficiency test. Five phenolic compounds were found to be very stable on adsorbent tubes for 4 days at room temperature. Detection limit of five phenolic compounds ranged from 0.05 to 0.08 ppb (when assumed to collect 10 L air). The calibration curve was linear over the range of 22∼ 164 ng. The reproducibility was less than 4%. Sampling of duplicate pairs (DPs) was made to demonstrate duplicate precision and sampling efficiency.

• Journal of Microbiology and Biotechnology
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• v.16 no.7
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• pp.1139-1143
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• 2006

Various techniques and strategies have been developed for the identification of intracellular metabolic conditions, and among them, isotope balance-based flux analysis with gas chromatography/mass spectrometry (GC/ MS) has recently become popular. Even though isotope balance-based flux analysis allows a more accurate estimation of intracellular fluxes, its application has been restricted to relatively small metabolic systems because of the limited number of measurable metabolites. In this paper, a strategy for incorporating isotope balance-based flux data obtained for a small network into metabolic flux analysis was examined as a feasible alternative allowing more accurate quantification of intracellular flux distribution in a large metabolic system. To impose GC/MS based data into a large metabolic network and obtain optimum flux distribution profile, data reconciliation procedure was applied. As a result, metabolic flux values of 308 intracellular reactions could be estimated from 29 GC/ MS based fluxes with higher accuracy.

• Toxicological Research
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• v.7 no.1
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• pp.29-35
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• 1991

Barbiturates are commonly abused tranquilizer and a rapid method to determine these drugs in biological samples is needed. In this study, was screened barbiturates in urine specimens by the fluorescence polarization immunoassay method(FPIA) and the positive samples were confirmed and identified by the more definitive GC/MS method. Fifteen positive smples which have barbiturate values higher than 0.5 ng/ml were analyzed by the GC/MS method. Eight samples were identified as phenobarbital and five samples were identified as crotilbarbitone.

• Elastomers and Composites
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• v.52 no.1
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• pp.59-68
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• 2017

The effect on the hydrolysis resistance properties by the addition of maleic anhydride grafted EMDM (MA-g-EPDM) and PP (MA-g-PP) to a PA66/GF composite was investigated with respect to the mechanical properties, thermal properties, and morphology. The degree of hydrolysis of the PA66/GF composite was measured using py-GC/MS analysis. When compared to the PA66/GFcomposite in MEG/water solution, the composites where MA-g-EPDM and MA-g-PP were added to PA66/GF showed a higher degree of hydrolysis resistance, impact strength, and thermal properties, whereas their tensile strength, tensile modulus, flexural strength and flexural modulus decreased. As immersion time in the solution increases, the rate of tensile strength drop of the MA-g-PP added composite appeared lower than that of the PA66/MA-g-EPDM/GF and PA66/GF composites. The py-GC/MS analysis confirmed the formation of PA66 hydrolysis reaction by products such as carboxylic acid and alkylamine with increasing immersion time.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.344-345
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• 2001

대기 중에는 ppb 수준의 매우 미량으로 많은 VOC 성분이 존재하고 있어 이를 효과적으로 신속하고 적은 비용으로 분석할 수 있는 분석할 필요성이 커지고 있다. 그러므로, 본 연구에서는 대기중의 VOC성분을 SPME-GC/MS법을 이용하여 효율적으로 분석하기 위한 분석법을 개발하고자 하였다. 유해성이 큰 halocarbon, aromatic, haloaromatic V()Cs 42 종(USEPA TO-14)과, 오존을 유발시키는 오존전구물질 VOCs 53 종, 국내 규제 VOCs 33종, 그리고 악취물질(국내 8종 포함 일본 악취물질 22종)을 전부 포함하는 111종의 VOC를 SPME-GC/MS를 이용하여 신속하게 정성, 정량분석할 수 있는 방법을 확립하고저 하였다. (중략)

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2006.05a
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• pp.209-213
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• 2006

본 연구는 재래흑돼지와 개량종 돼지 가열육의 SPME-GC/MS와 전자코를 이용한 휘발성 향기 성분 및 향기 패턴 비교를 구명하고자 실시하였으며, 평균 생시 체중이 70 kg인 재래흑돼지(거세돈) 5두와 103 kg인 개량종 돼지($Landrace{\times}Yorkshire$,거세돈) 5두를 도축후 뒷다리 부위를 시료로 이용하였다. SPME-GC/MS를 이용한 휘발성 향기 성분에서 6-mehtyl-1-heptanol이 재래흑돼지육에서만 검출되었고, 1-octen-3-ol과 benzaldehyde가 재래흑돼지육이 개량종 돼지육보다 유의적으로 높았다(p<0.05). 전자코의 PCA에 의한 향기 패턴은 두 품종간에 큰 차이를 보이지 않았다. 따라서 재래흑돼지 가열육이 개량종 돼지 가열육보다 높은 6-mehtyl-1-heptanol, 1-octen-3-ol, benzaldehyde를 가졌으며, SPME-GC/MS와 전자코에 의해 품종이 다른 가열 돈육의 휘발성 향기 성분과 패턴을 성공적으로 분별하였다.

• 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.