• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3151-3155
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• 2010

This study was performed to develop analytical methods to better understand the properties and reactivity of petroleum, which is a highly complex organic mixture, using high-resolution mass spectrometry and statistical analysis. Ten crude oil samples were analyzed using negative-mode electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). Clustering methods, including principle component analysis (PCA), hierarchical clustering analysis (HCA), and k-means clustering, were used to comparatively interpret the spectra. All the methods were consistent and showed that oxygen and sulfur-containing heteroatom species played important roles in clustering samples or peaks. The oxygen-containing samples had higher acidity than the other samples, and the clustering results were linked to properties of the crude oils. This study demonstrated that clustering methods provide a simple and effective way to interpret complex petroleomic data.

• Bulletin of the Korean Chemical Society
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• v.23 no.10
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• pp.1389-1393
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• 2002

The non-spectroscopic interference effects that occurred in inductively coupled plasma/mass spectrometry were studied for Ge, As and Se in human urine and serum. Many biological samples contain Na, K, Cl and organic compounds, which may cause the enhancement and depression on the analyte signal. The effect of 1% concomitant elements such as N, Cl, S, P, C, Na, and K on a 100 ㎍/L germanium, arsenic and selenium signal has been investigated by ICP/MS. The interference effects were not in the same direction. It appeared that concomitant elements such as Cl, S, and C induce an enhancement effect, whereas N and P did not show any significant effect. And, Na and K caused a depression. We have found a link between the abundance of analytes and the ionization potential of concomitant elements (eV), except carbon and nitrogen.

• Mass Spectrometry Letters
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• v.9 no.1
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• pp.37-40
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• 2018

Farinomalein is a maleimide-bearing compound well known for its anti-fungal activity. In the present study, synthesis of farinomalein is achieved via Stobbe condensation followed by Haval-Argade contrathermodynamic rearrangement. Kinetically driven Stobbe condensation followed by condensation with beta-alanine reveals formation of two isomers of farinomalein. This article describes application of LC-MS/MS in structure elucidation of farinomalein 1 and its isomers 2 and 3 encountered in its synthesis. The proposed distinct fragmentation pathway is supported by rational organic reaction mechanism. These fragmentation pathways are significant for analytical method development of farinomalein in near future. The structures of farinomalein 1 and its isomers 2 and 3 have been assigned undisputedly.

• Bulletin of the Korean Chemical Society
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• v.20 no.8
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• pp.910-916
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• 1999

A current interest in chemistry concerns traceability of analytical measurements to the International System of Units (SI) and the proper estimation of their uncertainties in accordance with the internationally agreed guide provided by the International Organization for Standardization (ISO). Isotope dilution mass spectrometry (IDMS) is regarded as a primary method, which make the measurement results traceable to SI units without significant empirical correction factors. Our laboratory, as the national standards institute of Korea, participated in an intercomparison of environmental analysis, pp'-DDE in corn oil, which was organized by the CCQM under supervision of the CIPM to test feasibility of IDMS as a primary method for the trace analysis of organic compounds. In this report, we provide basic equations used for the calculation of the concentration of the analyte in a sample and a precise description of the processes for the evaluation of the uncertainties of the measurement results. Also, we report the experimental conditions adopted to improve the accuracy of the IDMS measurement. The principles contained in ？？Guide to the Expression of Uncertainty in Measurement'' provided by ISO are followed for the uncertainty evaluation.

• Analytical Science and Technology
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• v.25 no.1
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• pp.60-68
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• 2012

A gas chromatography-mass spectrometric (GC-MS) method was developed for determining 25 semivolatile organic compounds in water. A 1.0 L water sample was placed in a separatory funnel and saturated with NaCl, and the solution was extracted two times with 40 mL of methylene chloride. Under the established condition, the linear quantification range was 0.02-800 ng/L and the relative standard deviation was less than 15%. The method was used to analyze 16 surface water samples collected from various regions in Gum-River. The samples revealed SVOC concentrations in the range of 0.02-96.8 ng/L. Maximum concentrations of VOCs detected were not exceeded the EPA or Germany guidelines in any of the samples. The developed method may be valuable for monitoring SVOCs in water.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.17 no.3
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• pp.77-84
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• 2017

Purpose: From the early 1990's, use of Tandem mass spectrometry in neonatal screening test, made early stage detection of disorders that was not detectable by the previous methods of inspection. This research aims to evaluate the frequency of positive results in national neonatal screening test by Tandem mass spectrometry and its usefulness. Methods: A designated organization for inherited metabolic disorder executed neonatal screening test on newborns using Tandem mass spectrometry from January 2006 to December 2015, followed by the investigation of these data by the Planned Population Federation of Korea (PPFK), and this research analyzed those inspected data from the PPFK. Results: Among total childbirth of 4,590,606, from January 2006 to December 2015, 3,445,238 were selected for MS/MS and conduction rate was 75.1%. 261 out of the selected 3,445,238 were confirmed patients and for last decade, detection rate of total metabolic disorder was 1/13,205. In 261 confirmed patients, 120 had an amino acid metabolic disorder and its detection rate was 1/28,710 and 110 had an organic acid metabolic disorder and detection rate was 1/31,320. Also, 31 had a fatty acid metabolic disorder and detection rate was 1/13,205. Conclusion: Inherited metabolic disorder is very rare. Until now, it was difficult to precisely grasp an understanding on the national incidence of inherited metabolic disorder, due to lack of overall data and inconsistent and incomplete long-term result analysis. However, this research attempted to comprehensively approach the domestic incidence, by analyzing previous 10 years of data.

• Bulletin of the Korean Chemical Society
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• v.35 no.7
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• pp.2057-2064
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• 2014

Thermochemical sulfate reduction (TSR) was conducted in autoclave on the system of crude oil and $MgSO_4$ at different temperatures. Gas chromatography pulsed flame photometric detector (GC-PFPD) was used to detected the composition of organic sulfur compounds in oil phase products. The results of the analysis indicate that with increased temperature, the contents of organic sulfur compounds with high molecular weight and thermal stability, such as benzothiophenes and dibenzothiophenes, gradually became dominated. In order to gain greater insight into the formation and distribution of organic sulphur compounds from TSR, positive ion electrospray Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used in detecting the detailed elemental composition and distribution of them. The mass spectra showed that the mass range of sulfur compounds was 200-550 Da. Four sulfur class species, $S_1$, $N_1S_1$, $O_1S_1$ and $O_2S_1$, were assigned in the positive-ion spectrum. Among the identified sulfur compounds, the $S_1$ class species was dominant. The most abundant $S_1$ class species increase associated with the DBE value and carbon number increasing which also indicates the evolution of organic sulfur compounds in TSR is from the labile series to the stable one. In pure blank pyrolysis experiments with crude oil cracking without TSR, different composition and distribution of organic sulfur compounds in oil phase products were seen from mass spectra in order to evaluate their pyrolysis behaviors without $MgSO_4$. FT-IR and XRD were used in analyzing the products of solid phases. Two distinct crystallographic phases MgO and $MgSO_4$ are found to coexist in the products which demonstrated the transformation of inorganic sulfur compounds into organosulfur compounds exist in TSR.

• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1393-1396
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• 2006

The 1+1 two-photon Resonant Enhanced Multiphoton Ionization (REMPI) spectra of 1,4-dichlorobenzene was obtained from 240 nm through to 250 nm on a laser mass spectrometer. Special care was taken to build up a heatable sample inlet system suitable for detecting a trace semi-volatile organic compound and reducing the memory effort on the inner wall of the inlet system. The detection limits of 1,4-dichlorobenzene in ppbV/V concentration range at certain wavelengths are presented.

• Journal of Genetic Medicine
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• v.5 no.1
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• pp.21-25
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• 2008

Purpose : In recent years, many countries have adopted newborn screening programs that use tandem mass spectrometry (MS/MS) to screen and the number of diseases screened has also increased. We began screening for inherited metabolic disorders using MS/MS in April, 2001. Our goal was to determine the overall prevalence of metabolic disorders and to assess the effectiveness of newborn screening by MS/MS in Korea. Methods : From April, 2001 to December, 2007, we screened newborns and high risk groups using MS/MS. Acylcarnitines and amino acids were extracted and butylated and were introduced into the inlet of MS/MS. Confirmatory testing including a repeat newborn screening, and urine organic acid and plasma amino acid analysis were performed on a case-by-case basis. Results : The total number of screened subjects 284,933 which comprised 251,799 neonates and 33,134 high risk subjects. The recall rate was 0.4% (1158 tests) and true positive cases were 117 (0.04%). Confirmed metabolic disorders (newborn/high risk group) were as follows; 78 (25/53) amino acid disorders, 27 (16/11) organic acid disorders, and 12 (5/7) fatty acid oxidation disorders. The estimated prevalence of inherited metabolic diseases in newborns was 1:5,000 and that in the total group was 1:2,000. Conclusion : Newborn screening by MS/MS improved the detection of many inherited metabolic disorders. We therefore propose that all newborns be screened by a MS/MS national program and followed-up using a systemic organization strategy.

• Journal of Microbiology and Biotechnology
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• v.11 no.1
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• pp.56-60
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• 2001

A kerosene fungus of Cladosporium resinae NK-1 was examined for its ability to degrade individual n-alkanes and aromatic hydrocarbons by gas chromatography-mass spectrometry, and its organic solvent-tolerance was investigated by making use of the water-organic solvent suspension culture method. It grew on a wide range of solvents of varying hydrophobicities and it was found to have tolerance to various kinds of toxic organic solvents (10%, v/v) such as n-alkanes, cyclohexane, xylene, styrene, and toluene. A hydrocarbon degradation experiment indicated that NK-1 had a greater n-alkane degrading ability compared to that of the other selected strains. C. resinae NK-1, which could utilize 8-16 carbon chain-length n-alkanes of medium chain-length as a carbon source, could not assimilate the shorter chain-length n-alkanes and aromatic hydrocarbons tested so far. The n-alkane degrading enzyme activity was found in the mycelial extract of the organism.