• Bulletin of the Korean Chemical Society
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• 제34권6호
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• pp.1783-1790
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• 2013

A simultaneous analytical method has been developed for the fluorimetric determination of haloacetonitriles (HANs) [dichloroacetonitrile (DCAN), trichloroacetonitrile (TCAN), dibromoacetonitrile (DBAN), haloacetamides [dichloroacetamide (DCAD), and trichloroacetamde (TCAD)] in drinking water by using the combined on-line perconcentration/reversed phase liquid chromatography (RPLC)-postcolumn detection system. This on-line perconcentration system was achieved by employing a precolumn packed with a commercial solid phase extraction (SPE) sorbent for the enrichment and purification of the target analytes. The haloacetonitriles and haloacetamides were separated on CN analytical column in a 7.5% methanol-0.02 M phosphate buffered mobile phase at pH 3. The column effluents were reacted with postcolumn reagents of ophthaldialdehyde (OPA) and sulfite ion at pH 11.5, to produce a highly fluorescent isoindole fluorophore, which were measured with a fluorescence detector. Under the optimized conditions for RPLC and the postcolumn derivatization system all of the coefficient of determination of the standard calibration curves for the target analytes were over 0.99 and had a linear range from 5 to 100 ${\mu}g/L$. The detection limits showed 1.6 ${\mu}g/L$ for DCAD, 0.1 ${\mu}g/L$ for TCAD, 0.6 ${\mu}g/L$ for DCAN, 1.6 ${\mu}g/L$ for TCAN and 1 ${\mu}g/L$ for DBAN, and the recoveries were ranged from 64 to 99% except for DCAD with precisions less than 4.9% in distilled water, and from 72(${\pm}4%$) to 116%(${\pm}2%$) in tap water.

• 분석과학
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• 제23권6호
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• pp.551-559
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• 2010

본 연구는 칼럼 전 유도체화와 HPLC-형광검출을 이용해 염소 소독 음용수 중 7가지 nitrosamine 화합물을 분석하는 방법을 추출 과정(액-액 추출 vs. 고상 추출)과 형광 유도체화 과정(denitrosation 및 dansylation)으로 나누어 평가하여 확립하였다. 최적화된 유도체화 방법으로 두 가지의 추출법을 비교하였을 때, Ambersorb 572를 이용한 고상 추출에 대한 회수율과 재현성(상대표준편차, RSD)이 각각 54.4-88.7%와 1.9-19.4%로 액-액 추출의 51.4-87.7%와 4.2-33.3%에 비해 더 좋게 나타났다. 확립된 방법은 기존의 HPLC를 이용한 분석 방법에 비해 회수율과 재현성 모두 개선되었으며, 방법검출한계(method detection limits, MDLs)는 0.5-4.4 ng/L이었다. 이 방법으로 춘천의 염소로 소독하는 두 곳의 정수장과 10 곳의 수도꼭지에서 채취한 물 시료 중 nitrosamine 화합물을 분석한 결과, N-nitrosodimethylamine (NDMA)이 주요 화합물이었으며, 농도 범위는 26.1-112 ng/L이었다.

• 한국식품과학회지
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• 제37권3호
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• pp.334-338
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• 2005

본 연구는 식품병마개 PVC 가스켓과 식품에 함유된 SEM을 효과적으로 분석하기 위해 연구했다. SEM은 발포제로 사용되는 ADC의 열분해산물로 알려졌다. 그러나 SEM은 분자량이 낮으며 ultraviolet light나 fluorescence에 활성을 갖지 않는다. 따라서 2-NBA-SEM으로 유도체화하여 HPLC triple column system으로 분석했을 때 상관관계는 0.9997이상이며 검출한계는 0.48ng/g으로 나타났다. 식품병마개 PVC 가스켓에서 SEM의 검출율은 77.08%로 나타났으며, 유통중인 병마개 PVC 가스켓에서 SEM은 812.20-5771.30ng/g 수준이였다. 그리고 회수율은 PVC 가스켓과 식품에서 각각 92.12-98.71%와 83.45-97.33%로 측정되었다.

• 분석과학
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• 제9권2호
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• pp.198-202
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• 1996

Histamine을 정확하고 신속하게 정량하기 위해 9-Fluorenylmethyl chloroformate를 형광유도체화제로 하여 역상 HPLC법으로 정량하였다. 히스타민을 형광유도체화할 때 반응액의 pH, 반응시간, 형광유도체화제의 농도 등 최적 반응 조건을 검토하였다. 이 방법으로 히스타민을 분석한 결과 $0.1{\sim}0.5{\mu}g/ml$의 농도범위에서 상관계수가 0.992인 양호한 직선성을 나타내였으며 검출한계는 $0.01{\mu}g/ml$였다.

• 한국식품조리과학회지
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• 제23권3호통권99호
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• pp.409-412
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• 2007

녹차재배의 대표적인 지역인 A, B 및 C지역에서 재배, 가공 처리되어 시판되는 녹차의 GABA 함량 분석결과, A와 C지역의 녹차의 GABA 함량은 비슷한 함량은 비슷하였으나, B지역의 것인 경우 GABA 함량의 변이가 현저하게 달랐다. 특히, 이 지역의 녹차의GABA 함량은 분석 시료 7종류에서 가장 높은 시료와 가장 낮은 시료가 같이 생산되고 있는 것으로 나타나, 녹차의 GABA 함량은 녹차의 지역간의 차이는 물론이고, 가공 처리 과정에 의한 함량 변이가 높은 것으로 사료된다. 본 연구에서는 녹차 의 대표적 생산지 3개의 지역에서 생산된 7개의 시판녹차 중 채엽시기에 따른 분류 중 중작만을 분석시료로 사용하였지만, 현재대형마켓에서 판매되는 녹차는 여러 지역에서 생산되는 수십 종류에 해당하며, 이들 시판녹차의 GABA함량은 또한 다양할 것으로 추정된다. 따라서, 추후에는 좀 더 많은 녹차시료에 대한 분석을 통해 현재 시판녹차의 평균 GABA 함량의 기준을 설정하고, 이를 바탕으로 생리활성 물질인 GABA가 다량 함유된 기능성건강 녹차식품 개발이 바람직할 것으로 사료된다.

• KSBB Journal
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• 제28권6호
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• pp.423-427
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• 2013

A new convenient derivatization method of ${\alpha}$-amino acid esters as nitrobenzoxadiazole (NBD) derivatives for chiral resolution was introduced and the enantiomer separation of ${\alpha}$-amino acid esters as NBD derivatives was performed by normal HPLC using chiral columns based on polysaccharide derivatives. The NBD derivatives were readily prepared by stirring NBD-Cl and ${\alpha}$-amino acid methyl ester HCl with $NaHCO_3$ in ethanol. The performance of Chiralpak IA was superior to the other chiral stationary phases for enantiomer resolution of NBD derivatives of several ${\alpha}$-amino acid methyl esters. Owing to fluorescence detection as well as strong UV absorption, it is expected that the convenient analytical method developed in this study will be very useful for enantiomer separation of ${\alpha}$-amino acid esters as NBD derivatives on polysaccharide-derived chiral columns.

• Mycobiology
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• 제42권4호
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• pp.339-345
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• 2014

During 2011~2013, a total of 729 samples for 19 types of medicinal plant were collected from Seoulyekryungsi in Seoul, Korea, and investigated for the presence of aflatoxins. The samples were analyzed using immunoaffinity column cleanup and high-performance liquid chromatography coupled to a fluorescence detector after post-column derivatization. Aflatoxins were found in 124 out of the 729 analyzed samples: 65 containing aflatoxin B1 (AFB1), 24 with aflatoxin B2 (AFB2), 15 with aflatoxin G1 (AFG1), and 20 samples with aflatoxin G2 (AFG2). The ranges for positive samples were $0.1{\sim}404.7{\mu}g/kg$ for AFB1, $0.1{\sim}10.0{\mu}g/kg$ for AFB2, $0.1{\sim}635.3{\mu}g/kg$ for AFG1, $0.1{\sim}182.5{\mu}g/kg$ for AFG2, and $0.1{\sim}1,043.9{\mu}g/kg$ for total aflatoxins. Most of the medicinal plant samples (721, 98.9%) were below legal limits, but 8 samples exceeded the legal limits of 10 and $15{\mu}g/kg$ established by the Korean standard for AFB1 and total aflatoxins (the sum of AFB1, AFB2, AFG1 and AFG2), respectively.

• 한국대기환경학회지
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• 제22권3호
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• pp.297-307
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• 2006

During January $2002{\sim}April\;2004$, hydrogen peroxide ($H_{2}O_{2}$) measurements were performed at the campus of Korea University, which is located in the northeastern part of Seoul. Gas phase hydroperoxide was collected in aqueous solution and separated by HPLC. Concentrations were determined by fluorescence using postcolumn enzyme derivatization. This measurement system was improved to be run automatically from sample collection at every 10 minutes through chemical analysis for data collection. Detection limits of $H_{2}O_{2}$ is $10{\sim}17\;pptv$, and the overall uncertainty of the measurements is better than 8%. Two-year measurements of $H_{2}O_{2}$ show typical seasonal variations. Concentrations of $H_{2}O_{2}$ were higher during $June{\sim}October$ and lower during $January{\sim}February$. Maximum concentration of 1-hour averaged $H_{2}O_{2}$ was 6.5 ppbv, which was observed in August and September. In general $H_{2}O_{2}$ concentrations were well correlated with $O_{3}$ concentrations and largely affected by meteorological factors such as temperature and wind direction.

• Bulletin of the Korean Chemical Society
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• 제25권6호
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• pp.900-906
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• 2004

An RPLC-postcolumn detection method has been developed for the fluorimetric determination of dichloroacetamide (DCAD) in water. After ammonia and DCAD were separated on a $C_{18}$ nonpolar stationary phase with 2.5% methanol-0.02 M phosphate buffer at pH 3, the column eluant was reacted with post column reagents, o-phthaldialdehyde (OPA) and sulfite ion at pH 11.5, to produce a highly fluorescent isoindole fluorophore, which was measured with a fluorescence detector ( ${\lambda}_{ex}$ = 363 nm, ${\lambda}_{em}$ = 425 nm). With the optimized conditions for RPLC and the postcolumn derivatization, the calibration curve was found to be linear in the concentration ranges of 0.5 and 20 ${\mu}$M for DCAD, and the detection limit for DCAD was 0.18 ${\mu}$M (23${\mu}$g/L). This corresponded to 18 pmol per 100 ${\mu}$L injection volume for a signal-to-noise ratio of 3, and the repeatability and reproducibility of this method were 1.0% and 2.5% for five replicate analyzes of 2 ${\mu}$M DCAD, respectively. The degradation yields DCAD to ammonia were 94 and 99%, and the percent recoveries of DCAD from 4 and 6 ${\mu}$M DCAD-spiked tap water were shown mean more than 97%.

• 약학회지
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• 제36권4호
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• pp.370-378
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• 1992

A simple and sensitive high performance liquid chromatographic method to quantitate ${\alpha}-keto$ acids in serum and urine was investigated. ${\alpha}-Keto$ acids react with 1,2-diamino-4,5-methylenedioxybenzene (DMB) in the presence of 2-mercapto-ethanol and sodium hydrogen sulfite to form highly fluorescent derivatives, substituted 6,7-methylenedioxyquinoxalinol. The derivatization procedure was performed in water bath at $100^{\circ}C$, and completed within 50 min. By the use of a reversed-phase column and multi-step gradient with two solvents, a mixture containing twelve of these derivatives were efficiently resolved within 35 minutes. The optimal wavelengh of the fluorescence detector are ${\lambda}_{ex}=364\;nm$ and ${\lambda}_{em}=445\;nm$. The quantitation of the individual ${\alpha}-Keto$ acids was reproducible with relative standard deviation of $3.0{\sim}7.9%$ and had a detection limits of $10{\sim}60$ fmol, except for p-hydroxyphenylpyruvic acid (960 fmol).