• Journal of Life Science
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• v.11 no.1
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• pp.19-23
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• 2001

To develop the effective microbial screening method, pyrolysis mass spectrometry (PyMS) fingerprinting was evaluated as a tool that discriminate various yeast strains. The target yeast strains were isolated from industrial wastewater. Seventeen environmental isolated yeast strains were examined by pyrolysis mass spectrometry and sequencing analysis of the large subunit rRNA gene D1/D2 region. The PyMS results were compared with those of sequencing analysis. Taxonomic correlations were observed between the PyMS data and the sequencing results. It was concluded that PyMS provides a rapid, reliable and cost-reducing method for discrimination of the yeast strains.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.2
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• pp.289-298
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• 2011

TMAH-based Py-MS has been investigated to apply for a real-time classification of biological agents in the field. Acquiring reproducible data from mass spectrometry is a key to biological detection in the field. Nevertheless, it has been little studied on what factors could affect to the reproducibility of the TMAH-based Py-MS spectrum patterns. Given the TMAH-based Py-MS applied to the field system, several factors which could affect to the reproducible pattern of TMAH-based Py-MS spectra are needed to be examined, including changes in TMAH injection volume, growth temperature for microorganism, and number of cells collected in pyrolyzer, and implication of stabilizer used for lyophilization. This study showed that the reproducibility of the spectrum patterns was significantly hindered by changes in TMAH concentration and cell number, and stabilizer implication but not by growth temperature. Among those at low TMAH concentration(0.015m) was not observed the significant alterations of the spectrum pattern even when its injection volume was changed, yet was in different cell numbers and stabilizer implication.

• Analytical Science and Technology
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• v.24 no.4
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• pp.256-265
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• 2011

Ambers have been used as a gemstone and a religious object since the ancient times and found in several archaeological sites in Korea. To prepare an enhanced conservation measures, we surveyed the chemical and spectroscopic properties of the ambers according to the provenance. Total 14 amber samples were collected from 6 different provenances including Baltic, Chiapas, Colombian, Dominican, Fushun and Madagascar amber. Infrared (IR) spectroscopic analysis was conducted for the non-destructive examination of the amber samples. They were also analyzed with pyrolysis/GC/MS (py/GC/MS) at the pyrolysis temperature of $300^{\circ}C$ with the on-line derivatization to trimethylsilyl ester. Baltic shoulder corresponding to the absorption at $1250cm^{-1}{\sim}1150cm^{-1}$ appeared in the IR spectrum of Baltic amber. IR spectra of the other ambers also showed somewhat distinctive characteristic peaks. In py/GC/MS analysis peaks assignable to succinic acid, dehydroabietic acid and pimaric acid were detected, which are known to be the components of the amber. In the meanwhile, the presence of compounds appearing in certain amber will be applied to differentiate the provenances of amber relics if their fragments are available for the analysis. These results are expected to help the confirmation of archaeological amber relics and archaeometric interpretation of provenances and manufacturing techniques.

• Journal of the Korean Wood Science and Technology
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• v.46 no.1
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• pp.1-9
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• 2018

Nowadays, synthetic resin varnish such as cashew nut shell liquid (CNSL) is being used as well as traditional lacquer. The code of ethics states that material must be identical to the original when preserving cultural heritage. Therefore, lacquer should be used. However, problem is that even experts have difficulties differentiating lacquer and CNSL as they have similar components. Therefore, this study was carried out to identify the difference between lacquer and CNSL using IR and Py-GC/MS. As a result of IR, in lacquer, $720cm^{-1}$ peak was detected and in CNSL, $750cm^{-1}$, $720cm^{-1}$ and $700cm^{-1}$ peaks were detected. The results of Py-GC/MS detect benzene compounds and alkyl chains for both varnishes. However, hexanoic acid was detected from CNSL but not lacquer. Using these analytical methods, the differences between lacquer and CNSL can be identified on the scene. This is expected to be applied to the authentic conservation and restoration of lacquerware.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.4
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• pp.719-725
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• 2011

To apply TMAH-based Py-MS to a field biological detection system for real-time classification of cell-type, reproducible patterns of the TMAH-based Py-MS spectra was known as a critical factor for classification but was seriously disturbed by quantity of cells injected into pyro-tube. This factor is an exterior variable that could not be complemented by improving the performance of the TMAH-based Py-MS instrument. One of idea to solve the knotty problem has been flashed from "Top-down proteomics for identification of intact microoganisms". That is, biomarker peaks are selected from complicate Py-MS spectra for intact microoganisms by tracing out their origins, based on Py-MS spectra for the featured components of different cell-types, in Top-down approach. This idea has been tested in classification of different Gram-type microoganisms. Through the analyses of spectra for the featured components - peptidoglycan and lipoteichoic acid for Gram-positive cells and lipopolysaccharide and lipid A for Gram-negative cells - with comparing to the spectra the corresponding Gram-type cells in the Top-down approach, biomarker peaks were selected to carry out PCA(Principal Component Analysis) in order to see classification of different Gram-types, resulting in significant improvement of their classification. Furthermore, weighting biomarker peaks on intact cell's spectra, based on the data for the featured components of the Gram-types, contributed to elevate classification performance.

• Elastomers and Composites
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• v.52 no.1
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• pp.59-68
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• 2017

The effect on the hydrolysis resistance properties by the addition of maleic anhydride grafted EMDM (MA-g-EPDM) and PP (MA-g-PP) to a PA66/GF composite was investigated with respect to the mechanical properties, thermal properties, and morphology. The degree of hydrolysis of the PA66/GF composite was measured using py-GC/MS analysis. When compared to the PA66/GFcomposite in MEG/water solution, the composites where MA-g-EPDM and MA-g-PP were added to PA66/GF showed a higher degree of hydrolysis resistance, impact strength, and thermal properties, whereas their tensile strength, tensile modulus, flexural strength and flexural modulus decreased. As immersion time in the solution increases, the rate of tensile strength drop of the MA-g-PP added composite appeared lower than that of the PA66/MA-g-EPDM/GF and PA66/GF composites. The py-GC/MS analysis confirmed the formation of PA66 hydrolysis reaction by products such as carboxylic acid and alkylamine with increasing immersion time.

• Elastomers and Composites
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• v.55 no.4
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• pp.281-288
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• 2020

A calibration curve is needed to determine the SBR and BR blend ratio of SBR/BR blend rubber compounds using pyrolysis-gas chromatography/mass chromatography (Py-GC/MS) or Py-GC. In general, a calibration curve is obtained using reference SBR/BR vulcanizates with various blend ratios. In this study, the calibration curves were obtained using reference samples made of rubber solutions and were compared to those plotted using the reference SBR/BR vulcanizates. Calibration curves using variations of 1,3-butadiene/styrene, 4-vinylcyclohexene (VCH)/styrene, 2-phenylpropene (PhP)/butadiene, PhP/VCH, 4-phenylcyclohexene (PhCH)/butadiene, and PhCH/VCH ratios with the BR content were examined for the suitability. We found that the calibration curves obtained using the mixed rubber solution references (1,3-butadiene/styrene and PhP/butadiene) could replace those constructed using the reference SBR/BR vulcanizates. The calibration curves of 1,3-butadiene/styrene and PhP/butadiene obtained using the raw references can be used for the determination of the SBR/BR blend ratios by applying some correction factors.

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

• Journal of Microbiology and Biotechnology
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• v.8 no.5
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• pp.523-530
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• 1998

Rapid and quantitative analysis of physiological change and clavulanic acid production was studied by the combination of pyrolysis mass spectrometry (PyMS) and artificial neural network (ANN) in Streptomyces clavuligerus. Firstly, the continuous culture studies were carried out to get the physiological background and PyMS samples. Clavulanic acid production was inversely related to growth rate: Mycelium growth and $q_{cal}$ were optimum at 0.1 $h^{-1}\; and \;0.025 h^{-1}$ respectively. Changes in specific nutrient uptake rates ($q_{gly}$ and $q_{amn}$) also affected clavulanic acid production since clavulanic acid production appeared to be stimulated by the limitation of carbon and nitrogen. Fermentation broth containing mycelium taken from continuous cultures was analyzed by PyMS, and the PyMS spectra were analyzed with multivariate statistics. PCCV plots revealed that samples harvested under the same culture condition were clustered together but samples from different culture conditions formed separate clusters. To deconvolute the pyrolysis mass spectra so as to obtain quantitative information on the concentration of clavulanic acid, ANN was trained on Py MS data using a radial basis function classifier. The results showed that the physiological stages with different growth rate were successfully differentiated and it was possible to monitor the clavulanic acid production precisely and rapidly.

• Applied Chemistry for Engineering
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• v.30 no.6
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• pp.707-711
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• 2019

The feasibility of waste concrete as a catalyst for the effective pyrolysis of polyethylene terephthalate (PET) was examined using thermogravimetric (TG) and pyrolyzer-gas chromatography/mass spectrometry (Py-GC/MS) analyses. TG analysis results indicated that the maximum decomposition temperature of PET is not altered by the use of waste concrete, showing similar values (407 ℃ and 408 ℃ at 5 ℃/min). Meanwhile, the volatile product distribution data obtained from the Py-GC/MS analysis revealed that the use of waste concrete promoted the deoxygenation reaction via converting the oxygen containing products such as benzoic acids, benzoates, and terephthalates to valuable deoxygenated aromatic hydrocarbons including benzene, toluene, ethylbenzene, and styrene. This suggests that the waste concrete can be used as a potential catalyst for the production of valuable aromatic hydrocarbons from PET pyrolysis.