• The Korean Journal of Pesticide Science
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• v.4 no.1
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• pp.1-10
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• 2000

The purpose of this study is to establish the assessment techniques of hazardous chemicals by the development of analytical method of biological samples. In this study, we have developed an extraction method of nine pesticides used for rice paddy that resulted in high recovery from the spiked human urine by the liquid-liquid extraction with diethyl ether at pH 7.0. Calibration curve obtained from each pesticide standard using by gas chromatography/mass spectrometry/selected ion monitoring has shown good linearity and detection limits were the range of $0.4{\sim}2.0$ ng/mL in urine. As a biological monitoring, urine samples of local farmers exposed directly to nine pesticides in the field were collected and analyzed by GC/MS. Of the tested pesticides, metabolites of phenthoate assumed were identified by GC/MS analysis. No parent compound was detected.

• Korean Journal of Food Science and Technology
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• v.43 no.5
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• pp.570-576
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• 2011

The effect of nuruks and crude amylolytic enzyme on free amino acid and volatile components of brown rice vinegar prepared by static cultures was investigated. Five groups consisted of AV (100% nuruk without crude amylolytic enzyme), BV (75% nuruk; 25% crude amylolytic enzyme), CV (50% nuruk; 50% crude amylolytic enzyme), DV (25% nuruk; 75% crude amylolytic enzyme) and EV (100% crude amylolytic enzyme without nuruk). Free amino acid content in AV vinegar (132.06 mg%) was lower than the others (184.56-191.22 mg%). Acetic acid, 3-methyl butyl acetate, acetoin and isoamyl alcohol were major volatile components as analyzed using gas chromatography-mass spectrometry after headspace solid-phase microextraction. Acetic acid in AV and EV samples represented 67.56% and 55.53% of total GC peak area, respectively. E-nose provided different patterns in each case showing variation in sensory properties.

• Korean Journal of Food Science and Technology
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• v.50 no.5
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• pp.464-473
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• 2018

The objective of the current study was to evaluate the effects of roasting methods on volatile flavor compounds of boricha using solvent-assisted flavor evaporation-gas chromatography (GC)-mass spectrometry and GC-olfactometry. The barley roasting methods tested were air roasting (AR), drum roasting (DR), and air/drum roasting (ADR). Twenty, twenty-one, and eighteen aroma-active compounds were detected in the products of AR, DR, and ADR, respectively. Guaiacol (smoky), 2-acetylpyrazine (almond-like), and furfuryl alcohol (burnt sugar-like) were detected as high intensity aroma-active compounds. Intensities of most aroma-active compounds produced by the DR method were higher. On the other hand, aroma intensities of phenols produced by the AR method, such as guaiacol and 2-methoxy-4-vinylphenol (curry-like), tended to be stronger. Aroma characteristics of phenols are not considered to be desirable for boricha. Although roasting time for DR was longer than that for AR, DR may be an effective barley roasting method for enhancing desirable aroma characteristics of boricha.

• Environmental Analysis Health and Toxicology
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• v.30
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• pp.2.1-2.9
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• 2015

Objectives This study aimed to evaluate the association between presence of depression symptoms and the exposure level to insecticides among aged population in rural area, determined via measured levels of urinary 3-phenoxybenzoic acid (3-PBA), after controlling for socioeconomic confounding factors. Methods Using a cross-sectional study design, we randomly recruited participants for our study (161 male and 239 female) from rural areas of Asan, Chungnam, Korea. Environmental risk factor exposure was assessed using a questionnaire, and gas chromatography-mass spectrometry was used to analyze urinary 3-PBA levels. We used a logistic regression analysis to assess the association of urinary 3-PBA levels with the presence of self-reported depression symptoms. Results After controlling for creatinine levels, the median (interquartile range) concentration of 3-PBA was approximately 1.5 times (p<0.05) higher among female (1.54 [0.90 to 2.35]) ${\mu}g/g$) than among male (1.06 [0.64 to 1.81] ${\mu}g/g$). Our study found that among female participants, the unit increase in 3-PBA levels exhibited a likely positive association (odds ratio, 1.12; 95% confidence interval, 1.00 to 1.25) with an increased risk of presence of self-reported depression symptoms, after adjusting for socioeconomic insurance type, daily physical condition, marital status, smoking status, and age. Conclusions Given our finding of a potential association between the presence of self-reported depression symptoms and 3-PBA levels, precautions should be considered to minimize exposure to insecticides and thus protect the health of aged residents in rural areas.

• Analytical Science and Technology
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• v.24 no.2
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• pp.119-126
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• 2011

Abstract: The amount of benzene, toluene, ethylbenzene, and o-xylene (BTEX) in 30 kinds of bottled waters purchased from market and 9 kinds of tap waters from home were determined using headspace solid phase microextraction (HS-SPME). The sample was stirred at 1200 RPM G for 4 min using a magnetic bar with $100\;{\mu}m$ PDMS as adsorbent for BTEX. Then it was desorbed from the fiber for 1 min at room temperature. Quantitation was achieved using standard calibration method. The limit of detection was determined as benzene 0.39 (${\pm}0.04$) ng/mL, toluene 0.08 (${\pm}0.04$) ng/mL, ethylbenzene 0.04 (${\pm}0.01$) ng/mL, and o-xylene 0.05 (${\pm}0.02$) ng/mL. Benzene and o-xylene were not detected in any samples, but toluene was detected in 11 samples, and ethylbenzene was detected just in 3 samples among 30 investigated bottled waters. The concentration range of investigated materials for toluene and o-xylene were $0.24({\pm}0.09)\sim2.95\;({\pm}0.08)\;ng/mL$, $0.08({\pm}0.06)\sim0.93({\pm}0.10)\;ng/mL$, respectively.

• Food Science and Preservation
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• v.21 no.3
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• pp.381-387
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• 2014

Food irradiation is one of the successful modern techniques used to preserve food. However, it needs very careful control. Detection of irradiated food is of prime importance to facilitate global trade and consumer assurance, choice, and protection. This study was performed to evaluate the radiation-induced hydrocarbon content of dried squid and octopus by e-beam irradiation. The samples were collected from supermarkets all over South Korea and irradiated with an e-beam at 0, 1, 3, 5, 7, and 10 kGy doses. Lipids were extracted with soxhelt, and the hydrocarbons induced with irradiation were separated via solid phase extraction (SPE) and identified via gas chromatography mass spectrometry (GC/MS). The major induced hydrocarbons in the irradiated dried squid and octopus were 1-tetradecene and pentadecane derived from palmitic acid and 1-hexadecene and heptadecane from stearic acid. The concentration of hydrocarbons differed from the composition of the fatty acid at the same radiation and increased according to the level of the radiation dose. The hydrocarbons induced by e-beam irradiation, including 1-tetradecene, 1-hexadecene, and heptadecane, were confirmed to have been the irradiation marker compounds. Therefore, they can be used to distinguish the e-beam-irradiated dried squid and octopus from the non-irradiated ones.

• Journal of Environmental Health Sciences
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• v.29 no.2
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• pp.50-55
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• 2003

3,3-dichlorobenzidine is suspected to be cancinogenic in experimental animal and human. Several studies have investigated excretion of metabolites in urine, hemoglobin adduction and cancer incidence among workers occupationally exposed to 3,3'-dichlorobenzidine. In these researches, metabolites of 3,3'-dichlorobenzidine had a very important role, and were required as highly purity. The purpose of this study was synthesis and isolation of its metabolites from 3,3'-dichlorobenzidine. 3,3'-dichlorobenzidine was partially dissolved in benzene, ether, ethanol and methanol, and completely dissolved in 70% acetic acid on mixtures of citric acid containing less than 1% DCB, pyridine, a mixture of 0.5N NaOH and toluene(1:2), and phenol saturated with 20 mM TRIZA base. DCB, monoacetyl-DCB and diacetyl-DCB were measured by using gas chromatography/mass spectrometry(GC/MS). Detection for checking them was nitrogen phosphorous detection mode(NPD), and for identifying them was selected ion monitoring mode(SIM). The base peaks were 252 m/z in DCB, 252, and 294 m/z in monoacetyl-DCB, and 252, 294 and 336 m/z in diacetyl-DCB, respectively. Diacetyl-DCB was synthesized by titrating DCB solution of pyridine with sufficient acetyl chloride. Precipitation was diacetyl-DCB, which was purity of 98.7%. And its supernatant was composed of DCB, monoacetyl-DCB and diacetyl-DCB. By using acetic acid as controller of acetylation, monoacetyl-DCB was isolated from diacetyl-DCB . And residual pyridine was removed by using acetone. The purity of monoacetyl-DCB was 98.8%.

• Journal of Gastric Cancer
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• v.1 no.3
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• pp.144-149
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• 2001

Purpose: Gastric stump cancer is defined as a cancer that develops in the stomach after a resection in cases of non-malignant or malignant gastric disease. The interval between the gastrectomy and the detection of gastric stump cancer must be over 5 years. Since duodenogastric reflux gastritis is a precancerous condition and one of the most important factors inducing gastric stump cancer, we compared the bile-acid content of gastric juice between gastric stump cancer patients and controls. Materials and Methods: To evaluate retrospectively the surgical treatment of patients with gastric stump cancer, we reviewed the cases histories of 1016 stomach cancer patients who had been operated on at the Department of General Surgery, Kosin University Gospel Hospital, between 1995 and 1998. The gastric juice was collected during the operations on the gastric stump cancer patients by using a needle puncture of the fundus of the stomach and during the endoscopic examinations of the control subjects. The samples were analyzed for various bile acids (gas chromatography/mass spectrometry). Results: The 6 gastric stump cancer cases accounted for $0.6\%$ of all gastric cancer patients; 5 patients were first operated on for a peptic ulcer and the remaining one for an adenocarcinoma of the stomach. All of the cases were men. The reconstruction method after the initial gastrectomy was a Billroth II in all cases. The sites of the gastric stump cancer were the anastomotic sitein 2 patients, the upper body in 2, the fundus in 1 and the cardia in 1. The operative methods were 3 total gastrectomies, 2 subtotal gastrectomies with Roux en Y anastomosis, and 1 partial gastrectomy with lymph node dissection and had a curative intention in all patients. All of the patients were still surviving at the time of this report. The gastric juices of 4 gastric stump patients showed significantly higher contents of cholic acid ($36.42{\mu}g/ml$) compared to the gastric juices of 35 control subjects ($36.42{\mu}g/ml$)(p$\leq0.0001$). Chenodeoxycholic acid and lithocholic acid were not significantly different. Conclusion: The gastric juice of gastric stump cancer patients contained a significantly higher cholic acid content. At the time of the initial gastrectomy, an operative method that prevents duodenogastric reflux may prevent or minimize the development of gastric stump cancer, and more aggressive surgical treatment may improve survival.

• The Korean Journal of Food And Nutrition
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• v.17 no.3
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• pp.260-265
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• 2004

Volatile components of pine needle(Pinus densiflora S.) were isolated by purge & trap headspace technique and analyzed by gas chromatography-mass spectrometry(GC-MS). And then volatile components were extracted for 2 hr and 20 hr at the two different temperature settings: room temperature and 60$^{\circ}C$. A total of 61 volatile components were identified by the four different conditions. These compounds are classified into six categories in terms of chemical functionality: 35 hydrocarbons, 16 alcohols, 4 carbonyls, 2 esters, 1 acid and 3 ethers. The major components were ${\alpha}$-pinene(1.5～15.7%), ${\beta}$-myrcene(13.2～15.6%), ${\beta}$-phellandrene(l2.0～16.0%) and cis-3-hexenol(4.0～18.3%). In the comparison of the four extraction conditions, longer extraction can be effective to extract components that have a high boiling point, but proved useless in obtaining low boiling point components. As a result of these experiments under the four different conditions, the 20 hr extraction at room temperature appeared to be the most optimized condition for the analysis of volatile compounds by using the purge & trap headspace technique.

• Journal of Ginseng Research
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• v.32 no.4
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• pp.305-310
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• 2008

The volatile constituents of the fresh roots of Panax ginseng C.A. Meyer have been investigated after treatment with artificial saliva and analysed by gas chromatography-mass spectrometry (GC-MS) using solid phase microextraction (SPME) fiber. Twenty peaks were detected in fresh ginseng, 5 of them were unknown peak, and mainly hydrocarbon components (${\alpha}$-pinene, ${\beta}$-pinene, myrcene, limonene, ${\beta}$-panasinsene, ${\beta}$-elemene, ${\beta}$-gurjunene, trans-caryophyllene, ${\alpha}$-gurjunene, ${\alpha}$-panasinsene, ${\alpha}$-neoclovene, trans-${\beta}$-farnasene, ${\alpha}$-humulene, ${\beta}$-neoclovene, ${\alpha}$-selinene, ${\beta}$-selinene, bicyclogermacrene) were detected. It's area percentage was increased about 10% in the fresh ginseng added artificial saliva during 40 minutes.