• Journal of Korean Society of Environmental Engineers
• /
• v.36 no.11
• /
• pp.764-770
• /
• 2014

This study assessed analysis of N-nitrosamines by separation, identification, and quantification using a gas chromatography (GC) mass spectrometer (MS) with electron impact (EI) mode. Samples were pretreated by a automated solid phase extraction (SPE) and a nitrogen concentration technique to detect low concentration ranges. The analysis results by EI-GC/MS (SIM) and EI-GC/MS/MS (MRM) on standard samples with no pretreatment exhibited similar results. On the other hand, the analysis of pretreated samples at low concentrations (i.e. ng/L levels) were not reliable with a EI-GC/MS due to the interferences from impurity peaks. The method detection limits of eight (8) N-nitrosamines by EI-GC/MS/MS analysis ranged from 0.76 to 2.09 ng/L, and the limits of quantification ranged from 2.41 to 6.65 ng/L. The precision and accuracy of the method were evaluated using spiked samples at concentrations of 10, 20 and 100 ng/L. The precision were 1.2~13.6%, and the accuracy were 80.4~121.8%. The $R^2$ of the calibration curves were greater than 0.999. The recovery rates for various environmental samples were evaluated with a surrogate material (NDPA-$d_{14}$) and ranged 86.2~122.3%. Thus, this method can be used to determine low (ng/L) levels of N-nitrosamines in water samples.

• Mass Spectrometry Letters
• /
• v.2 no.2
• /
• pp.33-36
• /
• 2011

The misuse of anabolic androgenic steroids is of particular concern in sports and society. Thus, it is of great importance to discriminate endogenous steroids such as testosterone or testosterone prohormones from their chemically identical synthetic copies. In this study, gas chromatography-combustion/isotope ratio mass spectrometric (GC-C/IRMS) method has been developed and validated for discriminating the origin of anabolic androgenic steroids. The method involves the solid-phase extraction, enzymatic hydrolysis with ${\beta}$-glucuronidase, HPLC-fractionation for the cleanup and analysis by GC-C/IRMS. The difference(${\Delta}^{13}C$) of urinary ${\delta}^{13}C$ values between synthetic analogues and endogenous reference compounds (ERC) by GC-C/IRMS was used to elucidate the origin of steroids, and intra- and inter-day precision, specificity and isotope fractionation were evaluated. The present GC-C/IRMS method combined with HPLC cleanup was accurate and reproducible enough to be successfully applied to the test of urine sample from suspected anabolic steroid abusers.

• Analytical Science and Technology
• /
• v.13 no.5
• /
• pp.592-600
• /
• 2000

The concentration of free fatty acids and fatty acid composition as well as cholesterol supersaturation in bile may be an important factor in the gallstone formation. Therefore, we simultaneously determinded 23 fatty acids in bile by selected ion monitoring (SIM) method of gas chromatography-mass spectrometry (GC-MS). Biliary fatty acids were extracted by aminopropyl column and the extracts with (phospholipid fraction) or without (free fatty acid fraction) alkaline hydrolysis of phospholipid were derivatized with MSTFA/TMCS (N-methyl-N-trimethylsilyl-trifluoroacetamide/trimethylsilylchloride) mixture in order to be detected on the GC-MS. The recovery range of this method was 61.1-99.0% and the RSD value of within-a-day and day-to-day test were 3.1-25.6% and 3.8-27.0%, respectively. Using this method, biliary profile was investigated in the bile of normal controls and patients with gallstones. The amounts and their distribution of free and phospholipid fatty acids showed different pattern between normal subjects and patients.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.31 no.3
• /
• pp.543-545
• /
• 2002

The volatile compounds in kimchi adsorbed with solid phase microextraction (SPM) were analyzed by using a gas chromatograph-atomic emission detector (GC-AED) and a gas chromatograph-mass spectrometer (GC-MSD). The volatile compounds were effectively adsorbed in SPME. Twenty five compounds such as dimethyl-sulfide were identified by GC-MSD and some of these were further confirmed to contain a sulfur and a nitrogen by GC-AED.

• Korean Journal of Veterinary Service
• /
• v.28 no.3
• /
• pp.285-294
• /
• 2005

This study was conducted to investigate the extraction method for the determination of organochlorine, organophosphorus and synthetic pyrethroid pesticide residues in beef fat by gas chromatography-mass selective detector(GC-MSD). Twenty one pesticide residues in fat were determined using a simple and rapid procedure based on solid- phase extraction(SPE) clean-up cartridges with octadecyl $(C_{18})-bonded$ porous silica, florisil, $10\%$ deactivated florisil. a tandem $C_{18}$ and florisil and a tandem $C_{18}$ and $10\%$ deactivated florisil. Solvent-solvent extraction using acetonitrile was not satisfied to eliminate fat interference for pesticide residue analysis by GC-MSD, and the recoveries of the method in fat ranged from 16.2 to $57.3\%$ except DDT$(83.2\%)$. The recoveries of SPE methods using a tandem $C_{18}$ and Florisil was $59.6\~123.8\%$ except fenitrothion $(135.2\%)$. the SPE method was verified the satisfactory performance of pre-treatment for pesticide residues analysis in fat by GC-MSD. The efficiency of florisil deactivated with $10\%$ water has been not proved significantly on recoveries of pesticide residues in fat.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.11 no.1
• /
• pp.38-42
• /
• 2006

When whole cells are subjected to pyrolysis gas chromatography/mass spectrometry (Py-GC/MS) analysis, it provides biochemical profiles containing overlapping signals of the majority of compounds. To determine marker compounds that discriminate embryogenic calluses from nonembryogenic calluses, samples of embryogenic and nonembryogenic calluses of five higher plant species were subjected to Py-GC/MS. Genetic programming of Py-GC/MS data was able to discriminate embryogenic calluses from nonembryogenic calluses. The content ratio of 5-meyhyl-2-furancarboxaldehyde and 5-(hydroxymethyl)-2-furancarboxaldehyde was greater in nonembryogenic calluses than in embryogenic calluses. However, the content ratio of phenol, p-cresol, and $^1H-indole$ in embryogenic calluses was 1.2 to 2.4 times greater than the ratio in nonembryogenic calluses. These pyrolysates seem to be derived from the components of the cell walls, which suggests that differences in cell wall components or changes in the architecture of the cell wall playa crucial role in determining the embryogenic competence of calluses.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2008.10a
• /
• pp.114-115
• /
• 2008

• Journal of Environmental Science International
• /
• v.9 no.1
• /
• pp.89-93
• /
• 2000

Twenty organic chemical substances(Table 2) were isolated from untreated wastewater, as well as treated wastewater, collected at 76 companys of 9 industry group located in the basin of Youngsan River. Those organic compounds were analyzed by Gas Chromatography/Mass Spectrometry(GC/MS) and confirmed through comparison with each standard reagents. Phenol, which was not detected in the raw wastewater, was identified in the effluent of treatment facility, indicating that phenol is generated from isopropylbenzene of plant wastewater.

• Analytical Science and Technology
• /
• v.21 no.6
• /
• pp.495-501
• /
• 2008

Agilent 5973 GC-MS instrument was modified so that the capillary direct interface was removed and that a silicone membrane was installed between GC and MS. Feasibility study of the membrane interface GC-MS has been carried out. Vacuum of the mass spectrometer was not affected by the carrier gas flow rate up to $4.7m{\ell}/min$. As the carrier flow rate was increased, peak tailing was reduced and chromatogram peaks appeared earlier. Chromatogram peaks showed better separation and higher sensitivity as the membrane thickness was reduced from $127{\mu}m$ to $75{\mu}m$, and also as the interface temperature was increased. However, the membrane interface GC-MS had drawbacks such as background ions at 73 and 147 m/z and poor peak separation due to peak tailing.

• Mass Spectrometry Letters
• /
• v.14 no.3
• /
• pp.104-109
• /
• 2023

Anabolic-androgenic steroids (AAS) are used illegally to enhance muscle development and increase strength and power. In this study, a reliable, and sensitive quantitative method was developed and validated using heptafluorobutyric acid anhydride (HFPA) derivatives for the simultaneous detection of prohibited AAS (testosterone [TS], boldenone [BD], 5α-estrane-3β,17α-diol [EAD]) using gas chromatography-tandem mass spectrometry (GC-MS/MS). For processing the samples, solid phase extraction, methanolic hydrolysis, and liquid-liquid extraction were used. For detection using mass spectrometry, the multiple reaction monitoring (MRM) mode was used with the electron ionization (EI) positive mode. The method was evaluated for selectivity, linearity, lower limit of quantification, intra- and inter-day precision, accuracy, and stability. The results showed that the method was accurate and reproducible for the quantitation of the three steroids. The developed method was finally applied to the analysis of a suspect gelding urine sample received from the Asian Quality Assurance Program (AQAP).