• 한국환경보건학회지
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• 제28권4호
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• pp.27-30
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• 2002

A thermal desorption-gas chromatography/mass spectrometric method was developed for the determination of methyl bromide in fumes formed during preservation of cultural materials from insects. Methyl bromide in lunes was collected by drawing 10ι of air through the adsorbent tube filled with a solid adsorbent (Chromosorb). The air samples were analyzed by using a special thermal desorption device and GC/MS determination. The recovery of methyl bromide by air sampling was 88% and the detection limit of the assay was 0.1 pptv based upon assayed air of 10ι. The method was applied to the determination of fumed methyl bromide used for the preservation of papers in a library. The mean concentration of methyl bromide determined in a library was 280.2 $\pm$ 25.4 pptv.

• 한국축산식품학회지
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• 제29권4호
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• pp.482-486
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• 2009

The aim of this study was to optimize a simple, fast, and economical analysis procedure for the determination of 16 different pesticides in raw milk via GC/MSD. Analyses were performed via gas chromatography with electron impact mass spectrometric detection in the selected ion monitoring mode (GC/MSD-SIM) using Pentachloronitrobenzene as the internal standard. The modified sample preparation methodology was based on the Pesticide Analytical Manual (PAM) of the FDA concerning fat extraction, ACN-ether partitioning, and clean-up of the Sep-Pak florisil cartridge. The modified methodology for the determination of the 16 pesticides was validated. The range of LOQs of the 16 pesticides was likely three times lower than their Maximum Residence Levels (MRLs). The recoveries of most of the pesticides were acceptable at the fortification levels of 0.5 and 1.0 ${\mu}g/mL$ and their RSD (%) level was less than 20%. None of the 16 pesticides were detected in the selected raw milk samples.

• Bulletin of the Korean Chemical Society
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• 제25권10호
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• pp.1508-1512
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• 2004

A gas chromatography/mass spectrometric (GC/MS) method has been developed for the determination of trace mono-n-butyltin (MBT), di-n-butyltin (DBT), and tri-n-butyltin (TBT) compounds in sediments. Samples were extracted by 10% acetic acid in methanol containing 0.03% tropolone and were then derivatized for GC/MS analysis. Ethylation by sodium tetraethylborate and phenylation by sodium tetraphenylborate were evaluated as a derivatization reaction of the organotins in sample extract. n-Hexane was added into reaction media in the beginning of the reaction for the continuous extraction of derivatized organotins. Ethylation requires less than 2 hours to get proper derivatization yields for MBT, DBT, and TBT altogether and produces relatively low amounts of side reaction products. Compared to ethylation, phenylation requires much longer time but provides relatively lower yield and produces considerable amounts of side reaction products. Therefore, the ethylation reaction was applied for the analysis of organotin compounds in sediment. An isotope dilution mass spectrometric (IDMS) method based on GC/MS has been applied to the accurate determination of DBT compounds in the sediments. The IDMS results from the analyses of sediment samples showed a reasonable repeatability and a good agreement with the values obtained by IDMS based on liquid chromatography/induced coupled plasma/mass spectrometry.

• Bulletin of the Korean Chemical Society
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• 제25권10호
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• pp.1489-1494
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• 2004

A gas chromatography/mass spectrometric assay method was developed for the determination of persistent organochlorine pollutants (POPs) in hair. For the exact extraction study was used hair of rat exposed with POPs. Sonication of the hair matrix with 3 M HCl solution in methylene chloride of the extraction methods studied was the most efficient and rapid sample preparation method. After sonication of rat hair was achieved clean up with a solid phase extraction procedure using silica gel-florisil. Elution was performed with 8 mL of methylene chloride. The eluate was concentrated to approximately 100 ${\mu}L$ and analyzed by gas chromatography-mass spectrometry (GC-MS). Detection limits of POPs were in the concentration range of 0.6-1.2 ng/g in rat hair. Aldrin, dieldrin, p,p-DDT and mirex were dosed rat for 4 weeks at concentration of 0.01 mg/L in drinking water and detected in rat hair at concentration of 2.8, 11.3, 7.9 and 15.6 ng/g, respectively. Aldrin and p,p-DDT were metabolized to dieldrin and p,p-DDE, which were detected in concentration of 9.7 and 2.9 ng/g in rat hair, respectively. The developed method may be valuable to be used to analyze POPs in human hair.

• 한국환경보건학회지
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• 제32권1호
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• pp.67-70
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• 2006

A gas chromatography/mass spectrometric method was developed for the determination of formaldehyde in hair. 0.3mg of hair was placed in 10ml headspace vial. 1.5mM pentafluorophenylhydrazine solution (pH 2) in 0.03 M phosphoric acid and $20\;{\mu}l$ of 500 mg/l $acetone-d_6$ as internal standard were added in vial and sealed tightly with cap. The solution was heated for 30 min at $90^{\circ}C$ in heating block. The extraction, the derivatization and the evaporation were performed simultaneously. After heating of the solution, 0.5 ml of headspace was taken up and analyzed by gas chromatography-mass spectrometry (GC-MS). Low limit of detection (LaD) and Low limit of quantitation (LOQ) of formaldehyde were 0.5 and 1.5 ng/g, respectively. The method was used to analyze formaldehyde in rat hair after oral exposure. The developed method may be valuable to be used to analyze formaldehyde in human hair.

• 분석과학
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• 제35권5호
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• pp.197-204
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• 2022

A gas chromatography-mass spectrometric method was developed for determining 5-chloro-2-methyl-4-isothiazolin-3-one (CMIT), 2-methyl-4-isothiazolin-3-one (MIT), 1,2-benzisothiazolin-3-one (BIT), 3-iodo-2-propynyl butyl carbamic acid (IPBC) and benzoic acid (BA) in household products. A 0.5 g sample was placed in a test tube and dissolved with 5 mL water, 5 mL methylene chloride and 1.0 mL methanol. The solution was extracted by ultra-sonication followed by mechanical shaking using the salting out effect. Under the established condition, the lowest quantification limits of all analytes were in the range of 0.04-10 mg/kg and their relative standard deviations were less than 8.0 %. The method was used to analyze 10 household products. As a result of analyzing 10 household products, MIT was detected in the range of 1.2-3.5 mg/kg in 3 of 10 samples, CMIT was detected in the range of 2.6-8.2 mg/kg in 3 of 10 samples, and BA was detected in the range of 5.0-15 mg/kg in 4 of 10 samples. Meanwhile, BIT and IPBC were not detected in any of the products. It has been shown that this method can be used for the simultaneous determination of biocides with various physical and chemical properties in household products.

• Bulletin of the Korean Chemical Society
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• 제29권5호
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• pp.985-987
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• 2008

Parathion is an organophosphate pesticide being legally applied for the purpose of agriculture and is being manufactured in Korea. A gas chromatography/mass spectrometric method was developed for the determination of parathion urinary metabolite, p-nitrophenol. p-Nitrophenol was extracted from weak acidic urine, and then measured by gas chromatography-mass spectrometry (selected ion monitoring). The recovery of pnitrophenol in the overall procedure was 88.2%. The detection limit of the assay was 1.0 $\mu$ g/L based upon assayed urine of 2.0 mL. The method was applied to the determination of p-nitrophenol in urine of workers of a parathion industry. Spot urines of workers of a parathion industry were sampled at the end of shift and pnitrophenol was analyzed using above developed method. p-Nitrophenol could be detected in all of the urine samples at concentrations varying from 3.0 to 681 $\mu$ g/L.

• Bulletin of the Korean Chemical Society
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• 제25권6호
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• pp.806-808
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• 2004

A gas chromatography/mass spectrometric assay method has been developed for the simultaneous determination of icing inhibitors, ethylene glycol monomethyl ether and diethylene glycol monomethyl ether in ground water contaminated with JP-8. Ethylene glycol monobutyl ether and ethylene glycol monoethyl ether were used as the internal standard and surrogate, respectively. 100 mL of ground water was extracted twice with 20 mL of methylene chloride. The extract was concentrated to dryness, dissolved with 100 ${\mu}$L of methanol and analyzed by GC-MS (SIM). The use of an Innowax column gave the peaks good chromatographic properties, and the extraction of these compounds from samples gave recoveries of about 50% with small variations. The method detection limits of the target compounds were in a range of 0.5-0.8 ng/mL in ground water.

• Bulletin of the Korean Chemical Society
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• 제22권7호
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• pp.685-688
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• 2001

A gas chromatography/mass spectrometric assay method has been developed for the simultaneous determination of benzidine (BZ), N-acetyl benzidine (ABZ) and N,N-diacetyl benzidine (DABZ) in rat urine. BZ, ABZ and DABZ were extracted from urine at pH 8 with ethyl ether. Conjugated urinary metabolites were extracted at pH 8 after hydrolysis with 1 M HCl for 30 min at 100 $^{\circ}C.$ The dried extract was dissolved in 100 ${\mu}{\ell}$ of ethylacetate and then injected in gas chromatography-mass spectrometric (GC-MS) system without further purification or modification. BZ, ABZ and DABZ have good chromatographic properties and offer very sensitive response for the EI-MS (SIM) without any derivatization. The recoveries for BZ, ABZ and DABZ were about 98.0, 81.8 and 71.4%, respectively, at pH 8.0 and the concentration of 5.0 ng/mL. The coefficients of variation of BZ and ABZ were less than 9.5% from 0.1 to 100 ng/mL and that of DABZ was less than 13% in the same concentration range. The detection limits of the assay were 0.01 ng/mL for both BZ and ABZ, and 0.05 ng/mL for DABZ in urine or plasma 1.0 mL.

• 한국연초학회지
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• 제30권2호
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• pp.117-124
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• 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.