• Analytical Science and Technology
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• v.22 no.1
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• pp.44-50
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• 2009

In this study, the use of purge & trap GC-MS technique for determination of methylmercury in sediment samples was described. The method detection limit of the method was determined as 0.06 ng/g and the recovery of the method was $102{\pm}11.4%$, with precisions better than 11.2%. The method was validated by analysis of CRMs such as ERM CC580 (estuarine sediment) and IAEA 405 (sediment). Additionally, the performance of the method was tested on river sediment samples and the analytical results were compared with those of the GC-CVAFS, which has been widely used for methylmercury analysis.

• Environmental Engineering Research
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• v.13 no.4
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• pp.216-223
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• 2008

An efficient method for the simultaneous determination of eleven phenolic endocrine-disrupting chemicals (EDCs) present in wastewater influent samples was described. The 11 phenolic EDCs including alkylphenols, chlorophenols, and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring (GC/MS-SIM) following two work-up methods for comparison; isobutoxycarbonyl (isoBOC) derivatization and tert-butyldimethylsilyl (TBDMS) derivatization. The wastewater influent samples containing the 11 EDCs were adjusted to pH 2 with $H_2SO_4$ and then cleaned up with n-hexane. Next, they were subjected to solid-phase extraction (SPE) with XAD-4 resin and subsequently converted to isoBOC or TBDMS derivatives for sensitivity analysis with gas chromatography/mass spectrometry-selected ion monitoring (GC/MSSIM). Following isoBOC derivatization and TBDMS derivatization, the recoveries were 86.6-105.2% and 97.6-142.7%, the limits of quantitation (LOQ) for the 11 phenolic EDCs for SIM was 0.001-0.050 ng/mL and 0.003-0.050 ng/mL, and the SIM responses were linear with the correlation coefficient varying by 0.9717-0.9995 and 0.9842-0.9980, respectively. When these methods were applied to five selected wastewater influent samples, for isoBOC derivatization and TBDMS derivatization the ranges of concentration detected were 0.2-99.6 ng/mL and 0.4-147.4 ng/mL, respectively.

• Korean Journal of Environmental Agriculture
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• v.37 no.2
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• pp.104-116
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• 2018

BACKGROUND: This experiment was conducted to establish a simultaneous analysis method for 7 kinds of herbicides in 3 different classes having similar physicochemical property as diphenyl ether(bifenox and oxyfluorfen), dinitroaniline (ethalfluralin and trifluralin), and chloroacetamide (metolachlor, pretilachlor, and thenylchlor) in crops using GC-ECD/MS. METHODS AND RESULTS: All the 7 pesticide residues were extracted with acetone from representative samples of five raw products which comprised apple, green pepper, Kimchi cabbage, hulled rice and soybean. The extract was diluted with saline water and directly partitioned into n-hexane/dichloromethane(80/20, v/v) to remove polar co-extractives in the aqueous phase. For the hulled rice and soybean samples, n-hexane/acetonitrile partition was additionally employed to remove non-polar lipids. The extract was finally purified by optimized Florisil column chromatography. The analytes were separated and quantitated by GLC with ECD using a DB-1 capillary column. Accuracy and precision of the proposed method was validated by the recovery experiment on every crop samples fortified with bifenox, ethalfluralin, metolachlor, oxyfluorfen, pretilachlor, thenylchlor, and trifluralin at 3 concentration levels per crop in each triplication. CONCLUSION: Mean recoveries of the 7 pesticide residues ranged from 75.7 to 114.8% in five representative agricultural commodities. The coefficients of variation were all less than 10%, irrespective of sample types and fortification levels. Limit of quantitation (LOQ) of the analytes were 0.004 (etahlfluralin and trifluralin), 0.008 (metolachlor and pretilachlor), 0.006 (thenylchlor), 0.002 (oxyfluorfen), and 0.02 (bifenox) 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 residues. Therefore, this analytical method was reproducible and sensitive enough to determine the residues of bifenox, ethalfluralin, metolachlor, oxyfluorfen, pretilachlor, thenylchlor, and trifluralin in agricultural commodities.

• Journal of Food Hygiene and Safety
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• v.33 no.4
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• pp.266-271
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• 2018

The Ministry of Food and Drug Safety (MFDS) is amending its test methods for health-functional foods (dietary food supplements) to establish regulatory standards and specifications in Korea. In this regard, we continue our research on developing analytical methods for the items. Octacosanol is the major component of polycosanol and is a high-molecular-mass primary fatty alcohol, obtained from sugar cane wax. Previous researchers have shown that octacosanol can lower cholesterol and has antiaggregatory properties, cytoprotective uses, and ergogenic properties for human health. Recently, octacosanol products have been actively introduced into the domestic market because of their functional biological activity. We have developed a sensitive and selective test method for octacosanol that the TMS derivatives by means of gas-chromatographic-tandem mass spectrometry (GC-MS). The trimethylsilyl ether derivative of the target analyte showed excellent chromatographic properties. The procedure was validated in the range of $12.5{\sim}200{\mu}g/L$. Standard calibration curves presented linearity with the correlation coefficient ($r^2$) > 0.999, and the limits of detection (LOD) and limits of quantitation (LOQ) were $4.5{\mu}g/L$ and $13.8{\mu}g/L$, respectively. The high recoveries (92.5 to 108.8%) and precision (1.8 to 2.4%) obtained are in accordance with the established validation criteria. Our research can provide scientific evidence to amend the octacosanol test method for the Health-Functional Food Code.

• 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 the Korean Chemical Society
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• v.56 no.5
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• pp.583-590
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• 2012

The HF (Hollow fiber) extraction method was optimized to analysis seven species of pesticides in aqueous sample and analyzing samples by GC/MS. Hollow fiber extraction showed good efficiency when it was conducted under these conditions: organic solvent was toluene and agitation speed was 1200 rpm. The 15% concentration of NaCl was optimized when it was experimented between 5% and 25%. The equilibrium time was determined at 15 minutes. The pH 5 showed the best effect on the extraction efficiency. The linearities of calibration curves of seven species were good with correlation of regression ($r^2$) over 0.995 when they were experimented over a concentration range of $5{\mu}g/L$ to $50{\mu}g/L$. The analytical data exhibited the detection of limits (LODs) range of $0.37{\mu}g/L$ to $1.23{\mu}g/L$ and the limit of quantification (LOQs) range of $1.19{\mu}g/L$ to $3.91{\mu}g/L$. The optimized HF-LPME extraction method provides a simple and effective preparation and requires small amount of organic solvents and samples compared to conventional pre-treatment methods.

• Applied Biological Chemistry
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• v.50 no.1
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• pp.29-35
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• 2007

Levels of ethyl carbamate, a potential carcinogen produced naturally during fermentation, in major Korean fermented foods and some selected alcoholic beverages were determined by GC/MS/SIM, and their average daily intake and excess cancer risk of Korean people were estimated. In GC/MS/SIM analysis average 1.41, 19.44, 3.00 and 170.88 ${\mu}$g/kg of ethyl carbamates were detected in Baechu kimchi, Japanese soy sauces, Soju and fruit brandy, respectively. The average and maximum daily exposures to ethyl carbamate through major Korean fermented foods and alcoholic beverage consumption were 9.42 and 35.75 ng/kg bw/day for Korean female aged 20-64 years, and 12.73 and 48.87 ng/kg bw/day for Korean male respectively, which were mainly contributed by Baechu kimchi, Japanese soy sauces, Soju and fruit brandy. The average and maximum excess cancer risks were $4.7{\times}10^{-7}$ and $1.8{\times}10^{-6}$ for Korean female, and $6.4{\times}10^{-7}$ and $2.4{\times}10^{-6}$ for Korean male. Therefore, the industries related to fermented foods and alcoholic beverages need to make an effort to reduce the amount of ethyl carbamate in their products.

• Analytical Science and Technology
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• v.15 no.2
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• pp.172-179
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• 2002

Determination were performed for the presence of three common environmental endocrine disrupting compounds (EDC), namely nonylphenol (NP), octylphenol (OP), di(2-ethylhexyl)phthalate (DEHP) in rainwater, distilled water, millipore water, groundwater, tap water, and bottle water in market, using OASIS cartrige extraction and GC/MS-SIM. Octylphenol was not detected in any water samples. The order of nonylphenol concentrations were increased in rainwater < millipore water < distilled water < groundwater < tap water < bottle water. The concentration of nonylphenol in bolltle water was $0.44{\mu}g/L$(ppb) at highest. Di(2-ethylhexyl)phthalates were detected in every water samples, and the concentrations were to be $1.70{\sim}2.92{\mu}g/L$ in rainwater, $8.7{\sim}31.7{\mu}g/L$ in distilled water, $0.6{\sim}5.6{\mu}g/L$(mean: $2.5{\pm}0.3{\mu}g/L$) in millipore water, and that were very stable values than other waters, $1.1{\sim}6.0{\mu}g/L$ in groundwater at near Jeonju, $3.1{\sim}5.8{\mu}g/L$ by means in tap water, $0.5{\sim}67.6{\mu}g/L$ in bottle water from market. The concentration of DEHP in bottle water samples from market were in higher than USEPA regulation at over 40%.

• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.894-898
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• 1999

Aroma components of Ookjook tea made from Polygonatum involucratum Maxim roots were collected and identified. The extraction of aroma compounds was accomplished by a simultaneous distillation and extraction method using a Likens and Nickerson's extraction apparatus. The concentrated extract was analyzed and identified by GC and GC-MS. The most abundant aroma components of this tea were furanic compounds including 2-furfural, 2-methyl-dihydro-3(2H)-furanone, 2-acetylfuran and 5-methylfurfural. These compounds seem to be originated from the thermal degradation of carbohydrates during the roasting process. Alkylpyrazines and acids including propionic acid increased slightly during the period of manufacturing process of Ookjook tea. Furanic compounds originated from the thermal degradation of carbohydrates and alkypyrazines from aminocarbonyl reaction seemed to be the important contributors to the aroma of the Ookjook tea.

• Journal of the Korean Society of Food Science and Nutrition
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• v.15 no.3
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• pp.258-262
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• 1986

The aroma component analysis of raw and cooked Korean edible mushroom (pleurotus ostreatus) by GC, GC-MS is as follows; 1) The volatile aroma component of raw mushroom is identified such as 3-octanol (46.01%), 3-octanone (18.75%), 1-octen-3-01 (15.39%), isobutyl alcohol (3.48%), and isoamyl alcohol (3.07%) consists 89.04% of total aroma component. 2) Meanwhile, the volatile aroma component of cooked one is identified as 16 kinds and six of them 1-octen-3-ol (66.50%), 3-octanol (10.99%), 3-octanone (9.77%), 1-octene-3-one (1.23%), octyl alcohol (1.12%), and octanol (0.96%) consists 89.61% of total aroma component. 3) The major compositions of aroma component of both raw and cooked ones carbonyl compounds and alcohols. Their number of carbons are $C_2-C_8$ short chain aliphatic compounds