• 분석과학
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• 제6권3호
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• pp.267-274
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• 1993

두 가지 파라미터를 이용한 반복 회귀 최적화법을 미셀 액체 크로마토그래피에서 아미노산과 팹티드류의 분리에 적용하였다. 실험에 사용한 파라미터들은 계면활성제(surfactant)인 SDS와 2-propanol의 농도이다. 이 최적화 방법은 작은 횟수의 초기 실험 수행으로 효과적인 최적화점을 얻을 수 있었다.

• 분석과학
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• 제7권1호
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• pp.11-15
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• 1994

한국에서 자생하는 삼백초(Saururus Chinensis)의 지상부에서 Quercetin 배당체인 Hyperin, Isoquercitrin, Quericitrin, Rutin등 4종의 Flavonoid들이 고성능 액체 크로마토그래피(HPLC), 기체 크로마토그래피(GC) 및 얇은막 크로마토그래피(TLC)를 이용하여 분리, 확인되었으며 주요 Flavonoid 성분으로 알려져 있는 Avicularin은 검출되지 않았다.

• 분석과학
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• 제12권6호
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• pp.583-586
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• 1999

The quantitative analysis of nitrate and nitrite in rain, milk and infant formula was done by Ion Chromatography. The nitrite was not detected(<0.1 mg/L) in all the samples. However, the nitrate was detected in the range of 0.1~4.9 mg/L in rain, 9.8~19.8 mg/L in milk, and 80~300 mg/L in infant formula, respectively. Some content of nitrate is close to the maximum contaminant level(MCL) which is 10 mg/L as $NO_3-N$, 44.3 mg/L as $NO_3$.

• 분석과학
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• 제8권4호
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• pp.405-410
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• 1995

A study on elemental speciation of trace metals in lake water (Lake Biwa in Japan) has been carried out by a size exclusion chromatography (SEC) / inductively coupled plasma mass spectrometry (ICP-MS) system. Before analysis, the water sample was preconcentrated with a ultrafiltration technique, where the large molecules with molecular weight larger than 10,000 were concentrated. Then the preconcentrated water samples (500-1000 fold) were analyzed by a SEC/ICP-MS system. Most trace metals were found at the UV absorption peaks corresponding to the molecular weights of ca. 300,000 and 10,000-50,000, where trace metals were on-line detected by ICP-MS. The results suggest that many of trace metals exist as the large organic molecules-metal complexes in natural water.

• 분석과학
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• 제11권6호
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• pp.495-498
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• 1998

The effect of high concentration ion matrix on the analysis of low anion concentration in the suppressed ion chromatography was studied. The anions studied were $Br^-$, $NO_3{^-}$, $HPO_4^{2-}$, $SO_4^{2-}$, and $C_2O_4^{2-}$ in the presence of excess NaCl and $CaCl_2$. In this study we suggested that the erroneous results in the suppressed ion chromatographic determination of small concentration of anions were not caused by the interaction of large amount of cation in the suppressor, but by the interaction of cation with concerned anion in the original solution. The error in the analysis of such anion can not be eliminated just by dilution. Therefore, we suggested that standard addition method might be adequate for analyses of those samples.

• 분석과학
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• 제16권1호
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• pp.59-69
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• 2003

Benzophenone (BZP) and 4-nitrotoluene (4-NT) listed as endocrine disrupting chemicals are suspected to contaminate ground water sites and soil. Analytical method for simultaneous determination of the two chemicals in soil and ground water was developed by gas chromatography-mass spectrometry. Water (100 ml) was extracted with hexane, and soil (10 g) was extracted with methanol and hexane. Recovery in water was >72% for BZP and 90-118% for 4-NT. Recovery for 4-NT and BZP in soil was 51-59% with coefficient variation of less than 19.5%. Calibration curves showed a good linearity with $r^2=0.997$. In water and soil collected at nation-wide sites, BZP was found at 5 sites among 43 water sites at the concentration of $14.87{\pm}3.83ng/100 ml$. No 4-NT was found. It is suggested that this method is appropriate to the simultaneous quantitation of 4-NT and BZP in ground water and soil samples.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.3114-3114
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• 2001

During the last years phytochemistry and phytopharmaceutical applications have developed rapidly and so there exists a high demand for faster and more efficient analysis techniques. Therefore we have established a near infrared transflectance spectroscopy (NIRS) method that allows a qualitative and quantitative determination of new polyphenolic pharmacological active leading compounds within a few seconds. As the NIR spectrometer has to be calibrated the compound of interest has at first to be characterized by using one or other a combination of chromatographic or electrophoretic separation techniques such as thin layer chromatography (TLC), high performance liquid chromatography (HPLC), capillary electrophoresis (CE), gas chromatography (GC) and capillary electrochromatography (CEC). Both structural elucidation and quantitative analysis of the phenolic compound is possible by direct coupling of the mentioned separation methods with a mass spectrometer (GC-MS, LC-MS/MS, CE-MS, CEC-MS) and a NMR spectrometer (LC-NMR). Furthermore the compound has to be isolated (NPLC, MPLC, prep. TLC, prep. HPLC) and its structure elucidated by spectroscopic techniques (UV, IR, HR-MS, NMR) and chemical synthesis. After that HPLC can be used to provide the reference data for the calibration step of the near infrared spectrometer. The NIRS calibration step is time consuming, which is compensated by short analysis times. After validation of the established NIRS method it is possible to determine the polyphenolic compound within seconds which allows to raise the efficiency in quality control and to reduce costs especially in the phytopharmaceutical industry.

• 한국물환경학회지
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• 제32권6호
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• pp.649-669
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• 2016

This study explored the analytical conditions for 21 veterinary antibiotics which have been popularly sold in South Korea in 2014 but have not yet been targeted in EPA method 1694. Most of the selected antibiotics were separated by a reverse-phase C18 column with a combination of (buffered) water and organic polar solvent, which was commonly methanol and acetonitrile in the gradient elution mode. Volatile additives such as formic acid, ammonium acetate and ammonium formate were usually added to the mobile phases to minimize asymmetrical and tailing of antibiotics' peaks and to increase their ionization in mass spectrometry. The analytical methods of aminoglycoside antibiotics were distinct from those of the other antibiotics in terms of adoption of ion-pair chromatography (IPC) and hydrophilic interaction liquid chromatography (HILIC) capable of retaining and separating extremely polar compounds due to their hydrophilicity. Trifluoroacetic acid or heptafluorobutyric acid was frequently added to the mobile phase as an ion-pair reagent for the IPC. Tandem mass spectrometry was numerously applied to the detection of antibiotics using positive electrospray ionization (ESI) and the selected reaction monitoring (SRM) mode. All reviewed analytical methods had been/were validated by evaluating recovery, limits of detection and quantification, decision limit or detection capability of the methods.

• Mass Spectrometry Letters
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• 제9권1호
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• pp.30-36
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• 2018

A quantitation method for free amino acids in human serum was developed using a stepwise-dilution method and a bimodal cation exchange (CEX)/hydrophilic interaction liquid chromatography (HILIC)-tandem mass spectrometry system equipped with an electrospray ionization source (ESI/MS/MS). This method, which was validated using quality control samples, was optimized for enhanced selectivity and sensitivity. Dithiothreitol (DTT) was used as a reducing agent to prevent the oxidation of a serum sample ($50{\mu}L$), which was then subjected to stepwise dilution using 3, 30, and 90 volumes of acetonitrile containing 0.1% formic acid. Chromatographic separation was performed on an Imtakt Intrada Amino Acid column ($50mm{\times}3mm$, $3{\mu}m$) in mixed mode packed with CEX and HILIC ligands embedded in the stationary phase. Underivatized free amino acids were eluted and separated within 10 min. As a result of the validation, the precision and accuracy for the inter- and intraday assays were determined as 2.11-11.51% and 92.82-109.40%, respectively. The lowest limit of quantification (LLOQ) was $0.5-4.0{\mu}g/mL$ and the matrix effect was 80.22-115.93%. The proposed method was successfully applied to the quantitative analysis of free amino acids in human serum.

• 한국식품과학회지
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• 제43권2호
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• pp.224-229
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• 2011

시중 유통 중인 과자류, 빵, 떡류, 면류 및 선식 등 432건을 immunoaffinity column으로 정제하여 HPLC-FLD로 제랄레논에 대한 오염실태를 조사하였다. 제랄레논의 검량선은 결정계수($R^2$)가 0.999 이상으로 양호한 직선성을 보였고 검출한계 및 정량한계는 각각 2.0, $6.0{\mu}g/kg$, 회수율 80.2-98.4%이었으며 RSD가 0.82-6.40%로 양호한 재현성을 나타내었다. 제랄레논 모니터링 결과, 과자류 중 스낵과자류 66건 중 3건에서 $6.02-11.82{\mu}g/kg$ 검출되었고 비스킷 71건 중 2건에서는 $14.78-17.83{\mu}g/kg$ 검출되었다. 면류, 빵류 및 떡류에서는 제랄레논이 검출되지 않았으며 침출차 14건에서 최고 $53.76{\mu}g/kg$ 검출, 선식 24건 중 16건에서 가장 높은 검출율(66.7%)을 나타내었다. 전분 2건, 시리얼두유 1건에서 제랄레논이 각각 5.55-8.56, $10.26{\mu}g/kg$ 검출되었다. 제랄레논 모니터링 결과는 기준이 설정되어 있는 유럽연합(곡류분말: $75{\mu}g/kg$, 빵, 비스킷, 스낵, 아침식사대용 시리얼류: $50{\mu}g/kg$, 영아 및 유아용 시리얼류: $20{\mu}g/kg$) 기준이하의 수준이었으며 국내외 연구보고와 비교한 결과 낮거나 비슷한 수준으로 검토되었다. 연구결과 곡류가공품에 대한 제랄레논 오염수준은 높지 않았으나 지구 온난화로 기후변화에 민감한 곰팡이독소와 같은 자연독소의 발생 증가가 우려되므로 선제적으로 대응하는 안전관리가 요구된다.