• Journal of the Korean Society of Tobacco Science
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• v.36 no.1
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• pp.26-33
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• 2014

Simultaneous determination of crop protection agents(CPAs) in food are done with multi-residue methods, which are composed of sample clean-up, concentration, chromatographic separation and detection. Stir Bar Sorptive Extraction(SBSE) technique is used for sample preparation of various analytes in several fields. The aim of this study was to develop a sensitive and fast method based on SBSE followed by thermal desorption - gas chromatography - mass spectrometry(TD - GC/MS) to determine CPAs in tobacco sample. For the analysis of tobacco sample prior to the SBSE method, solvent extraction or ultrasound-assisted solvent extraction was performed. methanol was used as the extraction solvent. The extract was then diluted with water. Finally, the sample was subjected to SBSE. A method for fast screening of crop protection agents in tobacco using SBSE-TD - GC/MS has been developed. About 17 CPAs including organochlorine, organophosphorous and others were identified and quantified. This method showed good linearity and high sensitivity for most of the target CPAs. The method was applied to the determination of CPAs at ng/mL levels in tobacco sample. This method is simple, rapid and may be applied in detection of other components.

• Bulletin of the Korean Chemical Society
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• v.25 no.4
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• pp.545-548
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• 2004

A sensitive, selective and rapid method for the determination of nickel based on the rapid reaction of nickel(II) with QADMAA and the solid phase extraction of the Ni(II)-QADMAA chelate with $C_{18}$ membrane disks has been developed. In the presence of pH 6.0 buffer solution and sodium dodecyl sulfonate (SDS) medium, QADMAA reacts with nickel to form a violet complex of a molar ratio of 1 : 2 (nickel to QADMAA). This chelate was enriched by solid phase extraction with $C_{18}$ membrane disks. An enrichment factor of 50 was obtained by elution of the chelates form the disks with the minimal amount of isopentyl alcohol. The molar absorptivity of the chelate was $1.32{\times}10^5L\;mol^{-1}cm^{- 1}$ at 590 nm in the measured solution. Beer's law was obeyed in the range of 0.01-0.6 ${\mu}$g/mL. This method was applied to the determination of nickel in water and biological samples with good results.

• Bulletin of the Korean Chemical Society
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• v.25 no.4
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• pp.549-552
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• 2004

A sensitive, selective and rapid method has been developed for the determination of mercury based on the rapid reaction of mercury(II) with p-sulfobenzylidenethiorhodanine (SBDTR) and the solid phase extraction of the colored chelate with $C_{18}$ disks. In the presence of pH 3.5 sodium acetate-acetic acid buffer solution and Emulsifier-OP medium, SBDTR reacts with mercury(II) to form a red chelate of a molar ratio 1 : 2 (mercury to SBDTR). This chelate was prconcentrated by solid phase extraction with $C_{18}$ disks. An enrichment factor of 50 was achieved. The molar absorptivity of the chelate is $1.28{\times}10^5 L{\cdot}mol^{-1}{\cdot}cm^{-1}$ at 545 nm in measured solution. Beer's law is obeyed in the range of 0.01-3 ${\mu}$g/mL. The relative standard deviation for eleven replicates sample of 0.01 ${\mu}$g/mL is 1.65%. This method was applied to the determination of mercury in tobacco and tobacco additive with good results.

• Bulletin of the Korean Chemical Society
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• v.25 no.2
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• pp.263-266
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• 2004

A sensitive, selective and rapid method has been developed for the determination ${\mu}$g/L level of vanadium ion based on the rapid reaction of vanadium(V) with 2-(2-quinolylazo)-5-diethylaminophenol (QADEAP) and the solid phase extraction of the colored chelate with $C_{18}$ cartridge. The QADEAP reacts with V(V) in the presence of citric acid-sodium hydroxide buffer solution (pH = 3.5) and cetyl trimethylammonium bromide (CTMAB) medium to form a violet chelate of a molar ratio 1 : 2 (V(V) to QADEAP). This chelate was enriched by solid phase extraction with $C_{18}$cartridge and the enrichment factor of 50 was obtained by elution of the chelates from the cartridge with ethanol. The molar absorptivity of the chelate is $1.28 {\times}10^5L\;mol^{-1}cm^{-1}$ at 590 nm in the measured solution. Beer's law is obeyed in the range of 0.01-0.6 ${\mu}$g/mL. The detection limit is 0.04 ${\mu}$g/L in the original samples. This method was applied to the determination of vanadium(V) in water and biological samples with good results.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.423.1-423.1
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• 2002

A simple. specific and sensitive method for the determination of cyclosporine A (CsA) in human serum has been developed by a high performance liquid chromatography/diode array detector (DAD) and applied to pharmacokinetic study of CsA. This method involves the use of solid phase extraction procedure following rapid protein precipitation with zinc sulphate from 1 $m\ell$ of human serum, using a disposable $C_{18}$ extraction cartridge. (omitted)

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.3
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• pp.586-592
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• 1999

Microwave assisted extraction(MAE) is known as a more environmental friendly process with economic advantages in terms of less time, less solvent, less energy and less wastes than the current time consuming reflux method. It was applied to develop a rapid extraction method for soluble ginseng components that are major materials used for the processing of ginseng products. In a comparative study between pre established MAE(ethanol 60%, power 80 W, process time 4 min$\times$5) and current extraction method(ethanol 80%, temp. 85oC, time 8 hr$\times$5), MAE was more efficient than the current method to obtain an extract yield(soluble solid), but it was insufficient to extract individual ginsenosides, total phenols, reducing components and acidic polysaccharides. MAE with 80% ethanol by 5 times showed, however, that its extraction efficiency on soluble solid, crude saponin, major ginsenosides, and the other components was equal or superior to that of the current method, indicating that ethanol concentration is one of the critical parameters influencing the MAE process. The quality of ginseng extracts from MAE was assured by evaluating the corresponding standards and by comparing TLC and HPLC patterns with the control.

• Bulletin of the Korean Chemical Society
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• v.29 no.2
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• pp.352-356
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• 2008

An analytical method has been developed for measuring chlorostyrenes in fish tissue sample. Extraction of chlorostyrenes from fish tissue was carried out by ultrasonication using acetone/n-hexane (5:2, v/v) mixture. Most of the lipids in the extract were eliminated by freezing-lipid filtration, prior to solid-phase extraction (SPE) cleanup. During freezing-lipid filtration, about 90% of the lipids extracted from the fish samples were easily removed without any significant losses of chlorostyrenes. For purification, SPE using Florisil was used for the rapid and effective cleanup. Quantification was performed using gas chromatography-mass spectrometry in the selected ion monitoring mode. Spiking experiments were carried out to determine the recovery, precision, and limits of detection (LODs) of the method. The overall recovery was above 80% in the spiked fish tissue sample at 10 and 100 ng/g levels, respectively. The detection limits for chlorostyrenes were ranged from 0.05 to 0.1 ng/g. This developed method is demonstrated to give efficient recoveries and LODs for detecting chlorostyrenes spiked into fish tissue with high lipid content.

• Mycobiology
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• v.42 no.4
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• pp.311-316
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• 2014

Lichen studies, including biodiversity, phylogenetic relationships, and conservation concerns require definitive species identification, however many lichens can be challenging to identify at the species level. Molecular techniques have shown efficacy in discriminating among lichen taxa, however, obtaining genomic DNA from herbarium and fresh lichen thalli by conventional methods has been difficult, because lichens contain high proteins, polysaccharides, and other complex compounds in their cell walls. Here we report a rapid, easy, and inexpensive protocol for extracting PCR-quality DNA from various lichen species. This method involves the following two steps: first, cell breakage using a beadbeater; and second, extraction, isolation, and precipitation of genomic DNA. The procedure requires approximately 10 mg of lichen thalli and can be completed within 20 min. The obtained DNAs were of sufficient quality and quantity to amplify the internal transcribed spacer region from the fungal and algal lichen components, as well as to sequence the amplified products. In addition, 26 different lichen taxa were tested, resulting in successful PCR products. The results of this study validated the experimental protocols, and clearly demonstrated the efficacy and value of our KCl extraction method applied in the fungal and algal samples.

• Plant Biotechnology Reports
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• v.4 no.1
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• pp.49-52
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• 2010

A DNA extraction method using Chelex 100 is widely used for bacteria, Chlamydomonas, and animal cell lines, but only rarely for plant materials due to the need for additional time-consuming and tedious steps. We have modified the Chelex 100 protocol and successfully developed a rapid and simple method of DNA extraction for efficient PCR-based detection of transgenes from a variety of transgenic plant and algal species. Our protocol consists of homogenizing plant tissue with a pestle, boiling the homogenized tissue in a microfuge tube with 5% Chelex 100 for 5 min, and centrifuging the boiled mixture. The supernatant, which is used for PCR analysis, was able to successfully amplify transgenes in transgenic tobacco, tomato, potato, Arabidopsis, rice, strawberry, Spirodela polyrhiza, Chlamydomonas, and Porphyra tenera. The entire DNA extraction procedure requires <15 min and is therefore comparable to that used for bacteria, Chlamydomonas, and animal cell lines.

• Analytical Science and Technology
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• v.31 no.3
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• pp.134-142
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• 2018

The uranium isotopic ratio in environmental samples around nuclear facilities is important because it reveals information regarding illegal activities or anthropogenic pollution. Determination of uranium isotopes, however, is a challenging task requiring much labor and time because of the complex separation procedures and lengthy process. In this study, a rapid determination method for uranium isotopes in environmental samples was developed using. The sample was completely decomposed using the alkali fusion method. The separation procedure using extraction chromatography (UTEVA) was simplified in a single step without any further removal process for Si and major matrix elements. The established method can be completed within 3 h from sample dissolution to ICP-MS measurement. Most matrix elements and uranium isotopes in the soil samples were well separated and purified. Five types of were used to assess the method's accuracy and precision for a rapid uranium analysis method. The analytical accuracy for all CRM samples ranged from 95.1 % to 97.8 %, and the relative standard deviation was below 3.9 %. From the analytical results, one may draw conclusions that the evaluated method for uranium isotopes using alkali-fusion, the extraction chromatography process, and ICP-MS measurements is fast and fairly reliable owing to its recovering efficiencies. Thus, it is expected that the evaluated method can contribute to the improvement of environmental monitoring ability.