• Bulletin of the Korean Chemical Society
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• v.21 no.11
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• pp.1101-1105
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• 2000

A simultaneous determination method of BTEX (benzene, toluene, ethylbenzene, o,m.p-xylene) and TPH (kerosene, diesel, jet fuel and bunker C) in soil with gas chromatography/flame ionization detection (GC-FID) was described. The effects of extracti on method, extraction solvent, solvent volume and extraction time on the extraction performance were studied. A sonication method was simpler and more efficient than Soxhlet or shaking methods. Sonication with 10 mL of acetone/methylene chloride (1 : 1, v/v) for 10 min was found to be optimal extraction conditions for 20 g of soil. Peak shapes and quantification of BTEX and TPH were excellent, with linear calibration curves over a wide range of 1-500 mg/L for BTEX and 10-5000 mg/L for TPH. Good reproducibilities by sonication were obtained, with the RSD values below 10%. By using about 20 g of soil, detection limits were 0.8 mg/L for BTEX and 10 mg/L for TPH. The advantages of this procedure are the use of simple and common equipment, reduced volumes of organic solvents, rapid extraction periods of less than 20 min, and simultaneous analysis of volatile and semivolatile compounds.

• Analytical Science and Technology
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• v.20 no.3
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• pp.255-260
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• 2007

A new method for the simultaneous determination of low molecular weight amines and quaternary ammonium ions based on the separation by IC with a suppressor and the detection by MS with ESI has been developed. The method has been applied to the analysis of a mixture containing tetramethylammonium ion, tetraethylammonium ion, tetrapropylammonium ion, triethanolamine, trimethylamine and triethylamine. The constituents were separated by isocratic elution using an IonPac CS17 column, a cation-exchange column, and detected by conductivity and mass spectrometry. The newly developed method for the six components demonstrated that the repeatability in terms of relative standard deviation for three measurements was in the range of 0.1-0.5 %. The detection limits were between 0.2 and $0.9{\mu}g/mL$ by the IC/ESI-MS.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.3
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• pp.375-383
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• 2023

Objectives: Coal-fired power plants feature diverse working conditions, including multi-layered employment structures and irregular work cycles due to outsourcing and non-standardized tasks. The current uniform occupational environment measurement systems have limitations in accurately assessing and evaluating these varied conditions. This study aims to propose alternative measurement and assessment strategies to supplement existing methods. Methods: Major domestic coal-fired power plants were selected as the study targets. To prepare for the study and establish strategies, work processes were identified and existing occupational environment measurement results were compared and analyzed. The study proceeded by employing three strategies: specific exposure groups (SEGs) measurement, continuous monitoring, and supplementary measurements, which were then compared and discussed. Results: Previous exposure index evaluations (5,268 cases) indicated that crystalline silica, a type of respirable particulate matter, had detection limits below the threshold (non-detectable) in 82.6% (4,349 cases) of instances. Exposures below 10% of the exposure limit were observed at a very low concentration of 96.1%. Similar exposure group measurements yielded results where detection limits were below the threshold in 38.2% of cases, and exposures below 10% of the limit were observed in 70.6%. Continuous monitoring indicated detection limits below the threshold in 12.6% of cases, and exposures below 10% of the limit were observed in 75.6%. Instances requiring active workplace management accounted for more than 30% of cases, with SEGs at 11.8% (four cases), showing a higher proportion compared to 3.0% (four cases) in continuous monitoring. For coal dust, exposures below 10% of the limit were highest in legal measurements at 90.2% (113 cases), followed by 74.0% (91 cases) in continuous monitoring, and 47.0% (16 cases) in SEGs. Instances exceeding 30% were most prevalent in SEGs at 14.7% (five cases), followed by legal measurements at 5.0% (eight cases), and continuous monitoring at 2.4% (three cases). When examining exposure levels through arithmetic means, crystalline silica was found to be 104.7% higher in SEGs at 0.0088 mg/m³ compared to 0.0043 mg/m³ in continuous monitoring. Coal dust measurements were highest in SEGs at 0.1247 mg/m³, followed by 0.1224 mg/m³ in legal measurements, and 0.0935 mg/m³ in continuous monitoring. Conclusions: Strategies involving SEGs measurement and continuous monitoring can enhance measurement reliability in environments with irregular work processes and frequent fluctuations in working conditions, as observed in coal-fired power plants. These strategies reduce the likelihood of omitting or underestimating processes and enhance measurement accuracy. In particular, a significant reduction in detection limits below the threshold for crystalline silica was observed. Supplementary measurements can identify worker exposure characteristics, uncover potential risks in blind spots of management, and provide a complementary method for legal measurements.

• Natural Product Sciences
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• v.22 no.4
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• pp.238-245
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• 2016

Gumiganghwal-tang has been used for the treatment of common cold for a long-time. We developed an accurate and sensitive high performance liquid chromatography-diode array detection (HPLC-DAD) and electrospray ionization mass spectrometry method for the simultaneous determination of ferulic acid, baicalin, bergapten, methyl eugenol, glycyrrhizin, oxypeucedanin, wogonin, nodakenin, atractylenolide III, imperatorin, and atractylenolide I in Gumiganghwal-tang samples. The analytes were separated on a Shiseido C18 column ($5{\mu}m$, $4.6mm\;I.D.{\times}250mm$) with gradient elution with acetonitrile and 0.1% trifluoroacetic acid. Eleven compounds were quantitatively determined by HPLC-DAD and identified by LC-MS data. We also validated this method. The calibration curves of all the compounds showed good linear regression. The limits of detection and the limits of quantification ranged from 0.04 to 0.63 and from 0.12 to $1.92{\mu}g/mL$, respectively. The relative standard deviation values of intra- and inter-days of this method represented less than 2.9%. The recoveries were found to be in the range of 90.06 - 107.66%. The developed method has been successfully applied to the analysis of Gumiganghwaltang samples. The established HPLC method could be used to quality control of Gumiganghwal-tang.

• Korean Journal of Veterinary Service
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• v.34 no.4
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• pp.429-439
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• 2011

This article described the comparison of a quick, easy, cheap, effective, rugged and safe (QuEChERS) sample preparation and the classical method established by National Veterinary Research and Quarantine Service (NVRQS) for the determination of pesticide residues in livestock products using GC-tandem mass spectrometry. The classical method by NVRQS used liquid-liquid partioning followed by evaporizing. The modified QuEChERS entailed extraction of 2 g sample with 15 ml acetonitrile containing 1% acetic acid followed by addition of 6 g anhydrous magnesium sulfate and 1.5 g sodium acetate. After centrifugation, 6 ml of the extract underwent a cleanup step (in a technique known as column-based solid phase extraction) using 400 mg each of $C_{18}$ and primary secondary amine sorbents plus 1,200 mg magnesium sulfate. The quantitation of individual pesticides by both methods was based on tissue standard calibration curves with a correlation coefficient in excess of 0.98 for the 24 pesticides. The detection limits by the classical method were ranged 1.3~5.0 ${\mu}g$/kg, with mean recoveries between 76.2% and 114.3% except aldrin (59.3%) and deltamethrin (63.6%). The detection limits by modified QuEChERS were ranged 0.3~6.2 ${\mu}g$/kg, with mean recoveries between 68.0% and 114.3% except dimethipin (152.6%), chlorfenvinphos (138.1%), 4,4-DDT (61.5%), aldrin (60.4%) and chinomethionate (30.3%).

• Food Science and Biotechnology
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• v.17 no.5
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• pp.925-930
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• 2008

Norovirus has become the most common cause of human gastroenteritis in developed countries. Detection procedures of foodborne viruses from foods require several steps. The concentration step using polyethylene glycol (PEG) is time-consuming and the detection efficiency of reverse transcription-polymerase chain reaction (RT-PCR) is affected by inhibitors from food components. In this study, a rapid detection method based on buoyant density centrifugation was developed to replace the time-consuming chloroform-polyethylene glycol-Tris Tween method. Feline calicivirus that belongs to the family Caliciviridae was used as a surrogate model for norovirus. After artificial inoculation of feline calcivirus (FCV) to oyster and lettuce, 830 ${\mu}L$ of homogenized sample suspension was layered on the top of 670 ${\mu}L$ 20% percoll and centrifuged. Then RNA extraction step was proceeded with the supernatant. By varying several physical conditions, the detection limits were lowered to $2.4{\times}10^2$ PFU per 1 g in oyster and $2.4{\times}10^0$ PFU per 1 g in lettuce. The protocol obtained in this study could be used to develop new detection method for norovirus in foods.

• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.284-289
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• 2004

A PCR assay for the rapid detection of Vibrio vulnificus strains was developed using a virulence gene for elastase found in various Vibrio species. The DNA sequences in the elastase gene facilitated the identification of a species-specific probe for pathogenic V. vulnificus strains from both clinical and environmental sources. Using an elastase gene-based PCR reaction, a species-specific 507-bp PCR product was visualized by agarose gel electrophoresis. Three different DNA extraction methods were then compared to improve the simplicity and rapidity of detection. A PCR assay using the conventional DNA extraction or boiling method was able to detect as few as 25 V. vulnificus cells, making the detection limits at least 1-log-scale lower than that for the EDT A-treated DNA extraction method. In particular, the boiling method, which does not require purification of the chromosomal DNA, was very effective in terms of simple and rapid detection. Meanwhile, the detection limit in a mixed bacterial culture that included other bacteria, such as Escherichia coli or Bacillus subtilis, was two V. vulnificus cells, which was 1-log-scale lower than that for the control. Accordingly, when coupled with a new DNA extraction method, the elastase gene-based PCR can provide a rapid, specific, and sensitive method for identifying V. vulnificus in clinical and environmental samples.

• Nuclear Engineering and Technology
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• v.55 no.11
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• pp.4039-4047
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• 2023

This contribution describes the application of HPGe detector for the airborne quantitative analysis. The hardware of the airborne HPGe system was designed from the commercial components with only exception of the newly designed AirHPGeSpec special software to control, measure and process the data. The system was calibrated for the local air kerma rates measured on helicopter board and its conversion to the air kerma rates at 1 m above the ground was proposed. Two examples of the air kerma rates measured over the former uranium mining areas are presented and compared with the results of other airborne system on the board. This airborne HPGe system could be also used for measuring the surface activities in a radiation event. The nuclides of ¹³¹I, ¹³²Te - ¹³²I, ¹³³I, ¹³⁴I, ¹³⁵I, ¹³⁷Cs, ¹³⁴Cs, ⁸⁸Rb and ¹⁰³Ru were selected from possible nuclear power plant emergency scenarios. The Monte Carlo simulation was used to calculate HPGe detector efficiencies for the flight altitudes from 25 to 300 m for the energies from 300 keV to 3 MeV of the nuclides in question. Also, the detection limits according to the Currie method as well as ISO 11929-2010 for selected nuclides are presented.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.17 no.2
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• pp.39-47
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• 2017

Purpose: A sensitive gas chromatography mass spectrometry (GC-MS) method was developed for screening of fatty acid oxidation disorders. Methods: The assay utilized a simple protein precipitation with sulfosalicylic acid followed by tert-butyl dimethylsilyl (TBDMS) derivatization of hydroxyl functional group by N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA). Results: Calibration curves of spiked pooled plasma showed a linear relationship in the range of 0.01 ng -2 mg with correlation coefficient value greater than 0.98. Limits of detection (LOD) and limits of quantification (LOQ) were found in the range of 0.9-8.8 ng and 9-88 ng, respectively. Conclusion: The new developed method might be useful for a rapid, sensitive screening of inherited fatty acid oxidation disorders. In addition, the method expected to be one of the alternative method for screening newborns of metabolic disorders in the laboratories where expensive MS/MS is unavailable.

• The Korean Journal of Food And Nutrition
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• v.35 no.6
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• pp.543-551
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• 2022

There has been increased interest in lignans due to their potential effect in reducing the risk of developing several diseases. To evaluate lignan contents, sensitive and accurate methods should be developed for their quantification in food. The present study aimed to validate a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of 5 lignans: lariciresinol (Lar), matairesinol (Mat), pinoresinol (Pin), secoisolariciresinol (Seco), and syringaresinol (Syr). The validation included selectivity, linearity, recovery, accuracy, and precision. The method was proved to be specific, with a linear response (R²≥0.99). The limits of detection were 0.040~0.765 ㎍/100 g and the limits of quantification were 0.114~1.532 ㎍/100 g. Recoveries were 90.588~109.053% for black sesame powder. Relative standard deviations of repeatability and reproducibility were below 5%. Total lignan contents of roasted coffee bean, oat, and blacksoy bean were 105.702 ㎍/100 g, 78.965 ㎍/100 g, and 165.521 ㎍/100 g, respectively. These results showed that LC-MS/MS analysis would be effective in producing acceptable sensitivity, accuracy, and precision in five lignan analyses.