• Analytical Science and Technology
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• v.28 no.1
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• pp.1-7
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• 2015

4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a tobacco specific nitrosamine found only in tobacco products. The ability to monitor biomarker concentrations is very important in understanding environmental tobacco smoke (ETS). In this study, an efficient and sensitive method for the analysis of NNK in dust was developed and validated using liquid chromatography tandem mass spectrometry. Dust was collected with filter paper soaked in methanol. The standard solution and dust sample were diluted with 100 mM ammonium acetate and extracted using dichloromethane. Our calibration curves ranged from 25 to $10^4pg/mL$. Excellent linearity was obtained with correlation coefficient values between 0.9996 and 1.0000. The limit of detection (LOD) was 5 pg/mL ($S/N{\geq}3$) and the retention time was 10 min. The limit of quantification (LOQ) was 25 pg/mL, and the acceptance criteria was the rate of 98-103% (80-120% at levels up to $3{\times}LOQ$). The coefficient of variations (CV) was 2.8%. Accuracies determined from dust samples spiked with four different levels of NNK racurves ranged that from 25 to 104 pg/mL. Excellent linearity was obtained between 92.1% and 114%. The precision of the method was acceptable (5% of CV). The recovery rates of the whole analytical procedure at low, medium, and high levels were 105.7-116.5% for NNK. The carry-over effects during LC-MS/MS analysis were not observed for NNK. This manuscript summarizes the scientific evidence on the use of markers to measure ETS.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.284-289
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• 2005

According to the nuclear safety regulation policy including the administration of radionuclides in low level radwastes, the evaporator bottoms were mixed with cement to form a stable solidification for identifying the recovery possibility of the C-14. The chemical oxidation method was applied for the extraction of C-14 from the cement waste form. The emitting beta ray of the C-14 extracted from the radwastes was measured with the liquid scintillation counter and calculated by using the quenching correction curves. Only the beta emitting radioactive nuclides of the C-14 in the radwastes was showed the radioactivities with the range of $2.7E+00\;{\sim}\;3.07E+02$ Bq/g.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.3
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• pp.179-183
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• 1998

The cyanidin 3-glucoside (C3G) extracted from pigmented rice seeds in 0.5% TFA (Trifluoro acetic acid) -95% ethanol was separated by High Performance Liquid Chromatography (HPLC). A HPLC system using a Develosil ODS-5 column and 0.1 % TFA-$H_2O$～0.1 % TFA-$CH_3CN$ gradient elution was selected for separation and quantitative determination of C3G. Regression equation obtained for the standard content of C3G pigment was as Y=21.95293$^*$X-14.726771 (r=0.99$^{**}$). Using this method, 326 domestic and introduced collections were evaluated for the C3G content. The Korean bred cultivar 'Heugjinjubyeo', showed highest C3G content (552 mg/100g seed) among the tested cultivars. Among the pigmented rice cultivars ten cultivars were selected for containing a high content of C3G. The content of C3G per 100g seeds was in high order as follows: Heugjinjubyeo (552mg)>Cheng Chang (321mg)>Kilimgeugmi (240mg)>PI160979-2 (224mg)>Hong Shei Lo (221mg)>Heugnambyeo (191 mg)>Mitak =PIl60979-1 (186mg)>Suwon425 (163mg)>Sanghaehyanghyeolla (108mg). The C3G pigment was not detected in the common white rice cultivars.

• Korean Journal of Food Science and Technology
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• v.43 no.3
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• pp.255-262
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• 2011

Auto- and photo-oxidative stability of oil extracted from germinated perilla seeds during storage at $60^{\circ}C$ for 4 days was studied by determining peroxide and conjugated dienoic acid values. Tocopherol contents during oil oxidation were also monitored by high performance liquid chromatography. Perilla oil was oxidized and tocopherols were degraded during storage at $60^{\circ}C$ regardless of the presence of light. Light increased oil oxidation and tocopherol degradation. Seeds germinated for 12 h had increased tocopherol contents in the oil and improved the auto- and photo-oxidative stability of the perilla oil. Tocopherol played a more important role as an antioxidant in the presence of light than in the absence of light.

• Restorative Dentistry and Endodontics
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• v.8 no.1
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• pp.107-113
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• 1982

The purpose of this study was to observe the tensile strength of composite resins to etched dentin surface with the various methods of placing bonding agent before composite resin or placing composite resin alone. Recently extracted 60 maxillary incisors were chosen. These were divided into 6 groups: Group I : Immediate Silar adaptation to the etched dentin surface with 37% phosphoric acid for 60 seconds without bonding agent. Group II : Immediate Silar adaptation to the etched dentin surface with 37% phosphoric acid for 60 seconds with bonding agent. Group III : Silar adaptation to the etched dentin surface with 37% phosphoric acid for 60 seconds after 5 minutes of bonding agent. Group IV : Immediate Enamelite adaptation to the etched dentin surfaces with 50% phosphoric acid for 120 seconds without bonding agent. Group V : Immediate Enamelite adaptation to the etched dentin surface with 50% phosphoric acid for 120 second s with bonding again. Group VI : Enamelite adaptation to the etched dentin surface with 50% phosphoric acid for 120 seconds after 5 minutes of bonding agent. All specimens were immersed in water at $37^{\circ}C$ for 24 hours before testing. The results were as follows: 1. The tensile strength of powder/liquid composite resin system was higher than that of pastel paste composite resin system. 2. The tensile strength of the composite resin group II, III, V, & VI with bonding agent was higher than that of the composite resin group I & IV without bonding agent. 3. The tensile strength of the composite resin group III & VI after 5 minutes added to bonding agent was higher than that of the composite resin group II & V immediately added to bonding agent.

• Korean Journal of Food Science and Technology
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• v.22 no.7
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• pp.732-737
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• 1990

In this study, the rutin contents in buckwheat and buckwheat foods were determined. Rutin in buckwheat and buckwheat foods was extracted with methanol and separated by High Performance Liquid Chromatography(HPLC) equipped with Lambda-Max Model 481 detector set at 355 nm using a ${\mu}$ Bondapak $C_{18}$ column and a 2.5% acetic acid:methanol:acetonitrile (35:5:10, v:v:v) solvent. There were differences in the rutin contents among the different species of buckwheat. The rutin contents in buckwheat groats were ranged from 8.84 mg to 24.77 mg/100g. The rutin contents in commercial buckwheat groats and flours were ranged from 15.04 mg to 20.92 mg/100g. The rutin contents in commercial dried buckwheat noodles, steamed buckwheat noodles, and buckwheat cookies were ranged from 1.76 mg to 10.84 mg/100g.

• Korean Journal of Agricultural Science
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• v.17 no.1
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• pp.52-64
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• 1990

As a search for natural antioxidants, antioxdative fractions in Pueraria roots were extracted, identified using column chromatography, thin layer chromatography or high performance liquid chromatography. The components which have most effective antioxidative activities were further identified by IR and GC-MS. Separated antioxidative components were then added to four different oils to examine their antioxidative activities. Yield of extract obtained from pueraria root powder by solvent extraction using four step solvent systems was 2.54%. Antioxidative activity of the extracts was as effective as that of 100 ppm ${\delta}$-tocopherol addition, when 0.1% of the extracts was added to linoleic acid. The strongest antioxidative component of methanol extract of pueraria root was identified as puerarin. Aunioxidative activity of puerarin on lard was more effective than ${\alpha}$-tocopherol, but less effective than ${\delta}$-tocopherol. When the puerarin was added to edible oil and heat treated at $145^{\circ}C$, the acid value was lowest in lard and was highest in soybean oil. Antioxidative activity in terms of carbonyl value, thiobarbituric acid value and anisidine value was most high in palm oil and least in soybean and cottonseed oil.

• Journal of Ginseng Research
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• v.44 no.4
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• pp.552-562
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• 2020

Background: Ginsenosides are the unique and bioactive components in ginseng. Ginsenosides are affected by the growing environment and conditions. In New Zealand (NZ), Panax ginseng Meyer (P. ginseng) is grown as a secondary crop under a pine tree canopy with an open-field forest environment. There is no thorough analysis reported about NZ-grown ginseng. Methods: Ginsenosides from NZ-grown P. ginseng in different parts (main root, fine root, rhizome, stem, and leaf) with different ages (6, 12, 13, and 14 years) were extracted by ultrasonic extraction and characterized by Liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry. Twenty-one ginsenosides in these samples were accurately quantified and relatively quantified with 13 ginsenoside standards. Results: All compounds were separated in 40 min, and a total of 102 ginsenosides were identified by matching MS spectra data with 23 standard references or published known ginsenosides from P. ginseng. The quantitative results showed that the total content of ginsenosides in various parts of P. ginseng varied, which was not obviously dependent on age. In the underground parts, the 13-year-old ginseng root contained more abundant ginsenosides among tested ginseng samples, whereas in the aboveground parts, the greatest amount of ginsenosides was from the 14-year-old sample. In addition, the amount of ginsenosides is higher in the leaf and fine root and much lower in the stem than in the other parts of P. ginseng. Conclusion: This study provides the first-ever comprehensive report on NZ-grown wild simulated P. ginseng.

• Mycobiology
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• v.41 no.4
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• pp.234-242
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• 2013

A total of 62 bacterial isolates were obtained from Gomsohang mud flat, Mohang mud flat, and Jeju Island, Republic of Korea. Among them, the isolate CNU114001 showed significant antagonistic activity against pathogenic fungi by dual culture method. The isolate CNU114001 was identified as Bacillus amyloliquefaciens by morphological observation and molecular data analysis, including 16SrDNA and gyraseA (gyrA) gene sequences. Antifungal substances of the isolate were extracted and purified by silica gel column chromatography, thin layer chromatography, and high performance liquid chromatography. The heat and UV ray stable compound was identified as iturin, a lipopeptide (LP). The isolate CNU114001 showed broad spectrum activity against 12 phytopathogenic fungi by dual culture method. The semi purified compound significantly inhibits the mycelial growth of pathogenic fungi (Alternaria panax, Botrytis cinera, Colletotrichum orbiculare, Penicillium digitatum, Pyricularia grisea and Sclerotinia sclerotiorum) at 200 ppm concentration. Spore germ tube elongation of Botrytis cinerea was inhibited by culture filtrate of the isolate. Crude antifungal substance showed antagonistic activity against cucumber scleotiorum rot in laboratory, and showed antagonistic activity against tomato gray mold, cucumber, and pumpkin powdery mildew in greenhouse condition.

• Korean Journal of Food Science and Technology
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• v.37 no.6
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• pp.1024-1027
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• 2005

Rapid and simple method was developed for simultaneous determination of vitamins $D_3\;and\;K_1$ contents in infant formula. Contents of vitamins $D_3\;and\;K_1$, extracted by column-switching HPLC with reversed phase column using enzymatic hydrolysis and organic solvent, in CRM determined by developed method were within certified ranges of standard values.