• 한국대기환경학회지
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• 제11권4호
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• pp.339-349
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• 1995

The purpose on this study is to optimize the chromatographic determination method of trace aldehydes in ambient air. Carbonyl compounds in urban air were trapped at $C_{18}$ DNPH-coated cartridges, and generated hydrazone derivatives were separated by HPLC and detected by UV-vis spectroscopic detector at 360nm. Formaldehyde and acetaldehyde compounds could be isolated from urban(Seoul) air with more than 95% collection efficiency. The analytical detection limits for formaldehyde and acetaldehyde are 0.06pp $b_{v}$, 0.08pp $b_{v}$ for 108 L air samples, respectively. The precision of this method are 3 .sim. 4%(RSD) for mutiple injection of hydrazone standards. Separation of seven dinitrophenylhydrazones could be achieved in appoximately 20 minutes operation time using $C_{18}$ column with apprepriate eluent. The method was applied to the analysis of aldehydes and ketone in Seoul ambient air. The 24-h ambient levels of formaldehyde, acetaldehyde reached up to 6 .sim. 14 and 3 .sim. 8ppbv, respectively. The daily average concentration ratio were 0.60 for acetaldehyde/formaldehyde.yde.

• 약학회지
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• 제39권3호
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• pp.283-288
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• 1995

Rapid gas chromatographic profiling method was applied to saliva from healthy subjects for the analysis of free organic acids. Saliva samples were first saturated with NaHCO$_{3}$ and extracted with diethyl ether. The aqueous phase was solid-phase extracted using Chromosorb P as the adsorbent and diethyl ether as the eluent after the acidification and NaCl saturation, followed by triethylamine treatment. The resulting tiiethylammonium salts of acids were directly converted into stable tert.-butyl-dimethylsflyl derivatives, with subsequent analysis by dual-capiuary column gas chromatography and gas chromatograpy -mass spectrometry. From the ten saliva samples studied, twenty eight free organic acids including various fatty acids, hydroxy acids, dicarboxylic acids, md aromatic acids were tentatively identified. Among the acids identified , the concentration of lactic acid was highest for five saliva samples while $\alpha$-hydroxyisocaproic acid was most abundant for me sample, and succinic acid and glycolic acid for two samples. respectively. When the GC profiles were simplified to the corresponding acid retention index spectra of bar graphical form, they presented characteristic patterns for each individual.

• 대한화장품학회지
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• 제14권1호
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• pp.1-15
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• 1988

A new method for liquid chromatography with post column reaction is suggested for the separation and quantification of tertiary amines. A mixture of triethanolamine and N-ethyl diethanolamine was separated by a strong cation exchange column, followed by spectrophtometric detection of the blue colors generated from the reaction of each amine with the Folin-Ciocalteau reagent. The tertiary amines were properly separated when an eluent of pH 9.5 containing 0.5M sodium nitrate was used. Under this condition, calibration curve of triethanolamine in 2-10mg/100ml concentration range was attained. Good results were obtained when cream and shampoo preparations containing known amount of triethanolamine were analysed according to this method. In case the sample did not contain any other interfering reducing substances, the amine was quantitatively determined by the simple reaction of the samples with Folin-Ciocalteau reagent, and the subsequent spectrophotometric measurement.

• Bulletin of the Korean Chemical Society
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• 제9권6호
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• pp.341-345
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• 1988

Separation of optical isomers of dansyl amino acids by a reversed phase liquid chromatography has been accomplished by adding a copper (II) chelate of N-benzyl-L-proline to the mobile phase. The pH, the eluent composition and the concentration of copper (II) chelate all affect the optical separations. The elution orders between D and L DNS-amino acids were consistant except dansyl phenylalanine showing that D forms of DNS-amino acids elute earlier than L forms. These behaviors are different from the results obtained by the use of copper (II) proline. The retention mechanism for the optical separation of the dansyl amino acids can be explained by the equilibrium of liqand exchange and by hydrophobic interaction.

• 대한화학회지
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• 제42권3호
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• pp.292-296
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• 1998

Amberlite IRC-718 킬레이트수지에서 Cu(Ⅱ)와 Fe(Ⅱ) 이온의 PSA(phenol sulfonic acid) 리간드에 의한 용리현상을 연구하였다. 여러 가지 농도의 PSA에 녹인 Cu(Ⅱ)와 Fe(Ⅱ) 용액 일정량을 수지에 흡착시키고 여러 가지 농도의 PSA로 용리하면 Cu(Ⅱ)와 Fe(Ⅱ) 이온이 각각 두 개의 봉우리로 용리되고, 이 두 개의 봉우리 면적을 PSA의 농도에 따라 변한다. 이를 이옹하여 두 이온과 PSA간의 착물의 안정도상수를 계산하였다. 그 값은 Cu(Ⅱ)는 7.0이고 Fe(Ⅱ)은 $4.5{\times}10^4$이었다.

• Bulletin of the Korean Chemical Society
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• 제25권7호
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• pp.1019-1024
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• 2004

The present paper is focused on simultaneous sorption concentration of gold (III) and silver (I) from thiocyanate solutions using high-selective anion exchanger AN-25 and subsequent separation of these ions at various concentrations of thiocarbamide (eluent). As a result, silver (I) ions are completely eluted from AN-25 and gold (III) ions remain in the resin phase and can be determined directly in the solid phase by diffuse reflection spectroscopy. It is proposed to use the sorption-spectroscopic method for Au(III) determination in aqueous solutions. The calibration curve is linear in the concentration range of 1-19 mg/L (sample volume is 10.0 mL) and the detection limit is 0.05 ${\mu}g/mL$. The presence of Cu(II), Co(II), Fe(II) do not hinder this determination. Au(III) was determined in industrial solutions.

• Journal of Microbiology and Biotechnology
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• 제27권6호
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• pp.1065-1070
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• 2017

This study aimed to examine the anti-candidal efficacy of a novel ketone derivative isolated from Diaporthe sp. ED2, an endophytic fungus residing in medicinal herb Orthosiphon stamieus Benth. The ethyl acetate extract of the fungal culture was separated by open column and reverse phase high-performance liquid chromatography (HPLC). The eluent at retention time 5.64 min in the HPLC system was the only compound that exhibited anti-candidal activity on Kirby-Bauer assay. The structure of the compound was also elucidated by nuclear magnetic resonance and spectroscopy techniques. The purified anti-candidal compound was obtained as a colorless solid and characterized as 3-hydroxy-5-methoxyhex-5-ene-2,4-dione. On broth microdilution assay, the compound also exhibited fungicidal activity on a clinical strain of Candida albicans at a minimal inhibitory concentration of $3.1{\mu}g/ml$. The killing kinetic analysis also revealed that the compound was fungicidal against C. albicans in a concentration- and time-dependent manner. The compound was heat-stable up to $70^{\circ}C$, but its anti-candidal activity was affected at pH 2.

• Bulletin of the Korean Chemical Society
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• 제28권4호
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• pp.601-606
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• 2007

The chromatographic behaviors of nucleotides (inosine 5'-monophosphate, uridine 5'-monophosphate, guanosine 5'-monophosphate, and thymine monophosphate disodium salts) on a C18 column were studied with different types of ionic liquids (ILs) as additives for the mobile phase in reversed-phase liquid chromatography (RPLC). Three ILs, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4]), 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIm][BF4]), and 1-ethyl-3-methylimidazolium methylsulfate ([EMIm][MS]), were used. Eluents were composed of water and methanol (90/10%, vol) with the addition of 0.5-13.0 mM of ILs. The effects of the concentration of ILs on retention and separation were investigated and discussed. The results showed that the addition of ILs affects the retention and resolution of the tested compounds. Use of 13.0 mM of [BMIm][BF4] as the eluent modifier resulted in a baseline separation of nucleotides without requiring gradient elution. This study demonstrates that ILs can be potentially applied as a mobile phase modifier in RPLC.

• 분석과학
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• 제13권5호
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• pp.601-607
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• 2000

란탄은 사용후핵연료의 연소도 지표원소들 중 하나로써 이용되고 있다. $U_3Si/Al$ 사용후핵연료는 다량의 U과 Al 속에 미량의 La이 포함되어 있어 정량시 매질의 영향을 줄이기 위해 화학적 분리가 요구된다. La의 분리 및 측정을 위해 IC-ICP-MS를 이용하였으며, 우선 방사성 시료를 취급하기 위하여 유도결합 플라스마 질량분석기의 플라스마 부분 및 분리관을 방사선 차폐 글로브박스 내에 설치하였다. CG10 분리관과 ${\alpha}$-HiBA 용리액을 사용하여 U, Al, La 및 몇 가지 핵분열생성물 (Sr, Zr, Y, Mo, Ru, Pd, Rh, Cs, Ba, Ce, Pr, Nd, Sm, Eu 및 Cd)의 머무름 거동을 살펴보았다. 0.2 M ${\alpha}$-HiBA 용리액에서 U과 Al이 초기에 용출되므로 분리관과 ICP-MS의 시료분무기 사이에 3방향 밸브를 연결하여 다량의 U과 Al이 ICP-MS로 유입되지 않도록 하므로써 매질의 영향을 줄일 수 있었다. 이 조건에서 La은 약 12분 정도에 분리 및 측정이 가능하였으며, $1-10{\mu}g/L$ (ppb)의 농도범위가 측청에 적합하였고 시료양을 $200{\mu}L$ 취할 경우 La의 검출한계는 $0.25{\mu}g/L$이었다.

• 대한화학회지
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• 제37권9호
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• pp.820-825
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• 1993

새로운 HDBPDA 이온교환체, {(4,5) : (13,14)-dibenzo-6,9,12-trioxa-3,15,21-triazabicyclo[15.3.l]heneicosa-(1,17,19)(18,20,21) triene ion exchanger: HDBPDA ion exchanger}의 이온교환용량은 3.8 meq/g이었다. 그리고 이 이온교환체에 대한 알칼리 및 알칼리토금속 이온들의 분포계수를 물과, 여러 농도의 염산용액중에서 측정하였다. 금속이온들의 분포계수는 염산농도의 영향을 거의 받지 않았으나, 대체적으로 염산의 농도가 감소할수록 점진적으로 약간 증가하는 경향을 보였다. 그리고 물속에서의 분포계수가 가장 컸다. HDBPDA 이온교환체를 사용하여 알칼리 및 알칼리토금속 이온들을 컬럼이온교환크로마토그래피로 분리하였으며, 이때 용리액으로 물을 사용하였다. 또한 알칼리 및 알칼리토금속 이온들의 분포계수는 그들 이온들의 이온반경이 증가함에 따라 증가하였다.