• 대한화학회지
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• 제8권2호
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• pp.85-87
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• 1964

Alloxan에 의한 Amino acids의 spot test에 있어서, alloxan수용액에 lactose를 가해주면, alloxan 자신의 착색을 막을 수 있다. lactose를 포함하는 alloxan수용액은 매우 안정하여서, 실온에서 수 개월 동안 두어도 착색되지 않으며, lactose의 존재로 말미암아, alloxan과 amino acids와의 색반응은 조금도 영향을 받지 않았다. 이시약에 의한 amino acids의 spot test법은 ninhydrin에 의한 spot test보다 예민하고, 또 alloxan 또는 dimethylalloxan을 발색약으로 사용하는 paper chromatography법에 비해, proline (1 ${\gamma}$), hydroxyprolin (5 ${\gamma}$)를 확인할 수 있다는 장점을 가지고 있다.

• 환경위생공학
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• 제23권4호
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• pp.37-44
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• 2008

In this study we developed the analytical methods for the determination of three neurotoxin; anatoxin-a, saxitoxin and neosaxitoxin using HPLC/FLD system and this analytical methods were applied to real sample; algae culture and algae extracts. For the HPLC/FLD analysis of anatoxin-a samples were concentrated on WCX(Weak Cation Exchanger) SPE and then anatoxin-a in concentrate was derivatized with NBD-F solution. Supernatant was injected on HPLC system. For the HPLC/FLD analysis of saxitoxin and neosaxitoxin samples were separated on the column and then derivatizied by post column reactor for fluorescen detection. For post column reaction of saxitoxin we feed two kinds of reaction solution; Oxidizing Reagent of which composition was periodic acid(7mM) in 50mM potassium phosphate buffer, pH 9 and acidifying reagent of which Composition was 0.5M acetic acid. The LOD value for anatoxin-a, saxitoxin and neosaxitoxin in HPLC/FLD method was 24.3 ng. $35{\mu}g/L$, $27{\mu}g/L$ respectively. We determined the anatoxin-a content of lyophilized anabaena flos-aquae and $20{\mu}g/g$ d.w. of anatoxin-a was detected. We analyzed saxitoxin and neosaxitoxin in algae culture media and extracts of lypopyllized algal cell cultured and that of Deachung reservior. Saxitoxin and neosaxitoxin in real sample were below the limit of detection. Although there are various water treatment processes for removing neurotoxins were suggested no process give simultaneous and complete removal of neurotoxins. It was cocluded that nanofiltration which reject material by size can be a process for removal of neurotoxins.

• Bulletin of the Korean Chemical Society
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• 제30권2호
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• pp.441-444
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• 2009

The formation and structure of self-assembled monolayers (SAMs) by the adsorption of acetyl-protected octylthioacetate (OTA) on Au(111) in a catalytic tetrabutylammonium cyanide (TBACN) solution were examined by means of scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV). Molecular-scale STM imaging revealed that OTA molecules on Au(111) in a pure solvent form disordered SAMs, whereas they form well-ordered SAMs showing a c(4 × 2) structure in a catalytic TBACN solution. XPS and CV measurements also revealed that OTA SAMs on Au(111) formed in a TBACN solution have a stronger chemisorbed peak in the S 2p region at 162 eV and a higher blocking effect compared to OTA SAMs formed in a pure solvent. In this study, we clearly demonstrate that TBACN can be used as an effective deprotecting reagent for obtaining well-ordered SAMs of thioacetyl-protected molecules on gold.

• 대한화학회지
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• 제34권1호
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• pp.98-101
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• 1990

스칸듐을 Methyl Thymol Blue(MTB)를 사용하여 가시선 흡수분광법으로 정량하는 새로운 방법을 확립하였고 주석슬러그에 스칸듐은 음이온교환수지와 용리액으로는 황산암모늄과 황산의 혼합용액을 사용하여 분리 회수하였다. 스칸듐과 MTB간의 착물의 결합비는 1:1이었고 최대흡수파장은 585nm이고 몰흡광계수는 $2.0 {\times} 10^4\;\iota{\cdot}mol^{-1}{\cdot}cm^{-1}$이다. 주석슬러그 용액을 음이온교환수지에 흡착시키고 위의 용리액으로 용리시키면 스칸듐 이외의 공존이온은 빨리 용출되고 늦게 용출되어 분리 회수된다.

• 한국환경과학회지
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• 제24권8호
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• pp.981-992
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• 2015

This study is mainly focused on micellar effect of tetradecyltrimethyl ammonium bromide(TTABr) solution including alkylbenzimidazole(R-BI) on dephosphorylation of diphenyl-4-nitrophenylphosphinate(DPNPIN) in carbonate buffer(pH 10.7). Dephosphorylation of DPNPIN is accelerated by $BI^{\Theta}$ ion in $10^2$ M Carbonate buffer(pH 10.7) of $4{\times}10^{-4}$ M TTABr solution up to 80 times as compared with the reaction in Carbonate buffer by no benzimidazole(BI) solution of TTABr. The value of pseudo first order rate constant($k_{\psi}$) of the reaction in TTABr solution reached a maximum rate constant increasing micelle concentration. The reaction mediated by $R-BI^{\Theta}$ in micellar solutions are obviously slower than those by $BI^{\Theta}$, and the reaction rate were decreased with increase of lengths of alkyl groups. It seems due to steric effect of alkyl groups of $R-BI^{\Theta}$ in Stern layer of micellar solution. The surfactant reagent, TTABr, strongly catalyzes the reaction of DPNPIN with R-BI and its anion($R-BI^{\Theta}$) in Carbonate buffer(pH 10.7). For example, $4{\times}10^{-4}$ M TTABr in $1{\times}10^{-4}$ M BI solution increase the rate constant($k_{\psi}=99.7{\times}10^{-4}1/sec$) of the dephosphorylation by a factor ca. 28, when compared with reaction($k_{\psi}=3.5{\times}10^{-4}1/sec$) in BI solution(without TTABr). And no TTABr solution, in BI solution increase the rate constant($k_{\psi}=3.5{\times}10^{-4}1/sec$) of the dephosphorylation by a factor ca. 39, when compared with reaction ($k_{\psi}=1.0{\times}10^{-5}1/sec$) in water solution(without BI).

• 분석과학
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• 제30권6호
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• pp.312-318
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• 2017

감열지에 부착된 잠재지문을 현출하는 시약으로 알려진 1,2-indandione/zinc (1,2-IND/Zn) 용액과 polyvinylpyrrolidone (PVP) 용액의 보존기한을 연구하였다. 감열지의 감열면과 비감열면에 출력세기가 동일한 인공잠재지문을 인쇄하여 이를 표준지문으로 사용하였다. 미리 혼합한 1,2-IND/Zn과 PVP 용액으로 표준지문을 처리한 결과, 혼합시약 제조 후 3 일까지는 감열지에 부착된 지문을 성공적으로 현출할 수 있었으나 3 일이 경과하면 감열지 표면에서 흑화현상이 나타나 시약의 성능이 저하되었다는 것을 알 수 있었다. 미리 혼합하지 않고 별도로 보관한 1,2-IND/Zn 및 PVP 용액을 사용직전에 혼합하여 표준지문에 부착된 잠재지문을 현출한 결과, 시약 제조 후 20 일이 경과하면 시약의 성능이 저하되는 것을 알 수 있었다. 또한, 1,2-indandione/zinc 용액과 polyvinylpyrrolidone 혼합용액의 보존기한은 polyvinylpyrrolidone 용액에 의해 결정된다는 것을 알 수 있었다. 산소와 수분 중 어느 것이 PVP의 성능저하에 영향을 미치는지 조사한 결과, 산소의 영향은 받지 않으나 수분의 영향을 받아서 시약의 성능이 저하된다는 것을 알 수 있었다.

• 환경위생공학
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• 제10권3호
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• pp.99-104
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• 1995

The objective of this study was to investigate the effect on denuclearization and decertification of flue gas by utilizing Mg( OH)$_{2}$ and NaOH as reagents in industrial boiler. We used packed absorber with Tellerette in all cases. And pH of circulation solution, rate of liquid per gas in absorber, COD concentration by pH variation in oxidation basin were inves- tigated. The following conclusions were obtained from experimental results: 1. Concerning running cost for reagents, Mg( OH)$_{2}$ reagent for treatment of flue gas was more economical than NaOH. 2. While Mg( OH )$_{2}$ and NaOH as absorbents were used, then the ratio of denuclearization was 96 and 97% respectively and nitrification was recorded 29 and 25% . 3. In this absorption tests the optimum condition for ratio of liquid per gas, pH and nonregenerable salt concentration of circulation solution were 3.6ℓ /Nm$^{3}$, 6.0, 0.5∼1.0% respectively, 4. Initial COD in oxidation basin was 800 ∼ 1,00099ut after adjusting to pH 7.0, COD of effluent water was less than 20ppm.

• 대한화학회지
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• 제17권6호
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• pp.439-443
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• 1973

은에 한하여 대단히 예민한 시약으로서 2-mercaptothiazoline를 알게 되었으며, 이 시약으로 은의 전류법 정량에 뛰어나게 이용할 수 있다. 이 방법은 암모니아 수용액에서 2-mercaptothiazoline으로써 전류법적정에 의한 미량의 은을 정량하는데 EDTA를 막기제로 사용하여 많은 다른 이온들의 존재하에 대기중에서 미량의 은을 직접 적정할 수가 있었으며 방해 이온들은 금과 백금 뿐이나, 미량의 은을 이 방법에 의하여 상대오차 ${\pm}$5% 이내로 정량할 수 있다.

• 대한화학회지
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• 제20권4호
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• pp.277-279
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• 1976

은 전극을 지시전극으로 하고 표준칼로멜 전극을 기준전극으로 하여 전압플로위회로를 이용하여 수용액에서 2,5-dimercapto-1,3,4-thiadiazole에 의한 구리의 전위차 적정법을 연구하였다. 이 시약은 구리의 전위차 적정 정량에 뛰어나게 이용할 수 있었고 여러가지 가리움제를 사용하여 다른 이온들의 존재하에 대기중에서 미량의 구리를 직접 적정할 수 있었다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.528-531
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• 2004

For a simple one-dimensional ignition problem a mathematical model is described to investigate the difficulties in numerical simulations. Some computation results are obtained and comparison is made with analytical solution. Discussions are made on topics such as 1) coordinate transformation, 2) gas-phase and solid-phase analysis; (divergence form of the governing system, a finite-volume discretization, implicit time integration, upwind split flux, spatial accuracy improvement are described. Mass, reagent mass, and energy conservations are solved.), and 3) method to determine quantities on the burning surface (matching). Results obtained for small values of the non-dimensional pressure show a steady-combustion and good agreement with the analytical solution. Numerical instability appeared for larger values of the pressure, discussion on the cause of the problem is made. This effort is a part of a study of flame spread phenomena on solid propellant surface.