• 대한화학회지
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• 제47권1호
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• pp.19-25
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• 2003

흡수 분광법에 의해 얻은 스펙트럼을 주성분분석(principal analysis, PCA) 으로 자료를 요약하여 주성분 회귀분서(principal component regression, PCR)과 부분 최소자승법(partial least squares, PLS)으로 음이온과 비이온 계면활성제(anionic and nonionic surfactant)를 동시에 정량하는 방법에 대하여 연구하였다. 두 가지 계면활성제가 서로 다른 농도로 혼합되어 있는 26개의 시료용액을 400~700 nm 범위에서 스펙트럼을 얻었고, 이를 이용하여 PCR과 PLS회귀모델을 얻었다. 두 가지 계면활성제가 서로 다른 농도로 포함된 5개의 외부검정용 시료들의 스펙트럼들을 이용해서 회귀모델의 적합성을 검정하기 위하여 외부검정용 시료의 농도를 계산하였다. 계산된 농도를 이용하여 relative standard error of prediction(RSEP$_{\alpha}$)를 구하여 회귀모델의 적합성을 검정하였다.

• 대한화학회지
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• 제40권4호
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• pp.254-263
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• 1996

두 자리 또는 세 자리의 질소 리간드를 갖는 5종류의 코발트(III) 착물을 합성하였다. 이 착물들의 촉매 작용을 질소의 위치가 다른 세 종류의 기질, 즉 P-Nitrophenyl Picolinate, P-Nitrophenyl nicotinate, 및 P-Nitrophenyl isonicotinate의 가수분해 반응에 대하여 자외선 분광법으로 측정하였다. 이 세 가지 기질 중에서 P-Nitrophenyl Picolinate가 촉매에 가장 민감한 반응을 보였으며, 이 화합물의 가수분해 반응은 pquohydroxo형태의 착물이 가장 많이 존재하는 pH 6.5에서 이 촉매들에 의하여 21-40배 촉진 되었다. P-Nitrophenyl Picolinate의 가수분해 반응에 대한 착물의 효과는 $Co(ibpn)(OH)>Co(aepn)(OH)_2(OH_2)>Co(tn)_2(OH)(OH_2)>Co(bpy)_2(OH)(OH_2)>Co(dien)(OH)_2(OH_2)$와 같이 나타났으며 이 가수 분해 반응은 분자내 일반 염기성 촉매 반응이 우세한 과정을 따르며 부분적으로 분자내 친핵성 촉매반응 메카니즘을 따르고 있음을 알 수 있었다.

• 대한화학회지
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• 제37권6호
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• pp.555-561
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• 1993

메탄올용매내에서 요오드와 테트라메틸주석 사이의 Iododestannylation에 대한 반응속도를 분광학적 방법으로 연구하였다. 이 결과로부터 일시적인 전하이동착물의 흡수 스펙트럼이 관찰되었으며, 흡수 스펙트럼의 후속적인 감소현상으로 요오드에 의한 테트라메틸주석의 분해반응임을 알았다. 따라서 iododestannylation에 대한 속도상수를 온도 10, 25 및 35$^{\circ}C$ 압력을 1600 bar 까지 변화시켜 가면서 측정하였으며, 이때의 반응속도상수는 온도와 압력에 따라 증가함을 알았다. 이 반응속도상수로부터 ${\Delta}V^\neq,\;{\Delta}{\beta}^{\neq},\;{\Delta}H^{\neq},\;{\Delta}S^{\neq}$ 및 ${\Delta}G^{\neq}$의 값을 구하였다. 활성화 부피와 활성화 압축율계수는 모두 음의 값이며, 활성화 엔탈피는 양의 값을, 활성화 엔트로피는 음의 값을 나타내었다. 이들 값으로부터 전이상태의 용매구조변화 및 메카니즘을 규명하였다. 이러한 사실로부터 본 반응은 $S_E2$ 메카니즘이 지배적이며 압력이 증가함에 따라 $S_E2$의 성격이 약화됨을 알았다

• 약학회지
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• 제30권1호
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• pp.42-46
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• 1986

The binding characteristics of five cephalosporins, cefamandole, ceftriaxone, cefoxitin, latamoxef, and cefotetan to bovine serum albumin (BSA) was examined by UV difference spectrophotometry. 2-(4'-hydroxybenzeneazo) benzoic acid was used as the spectrophotometric probe. Competitive bindings between the probe and cephalosporins were observed. Based on the Scatchard plot, the BSA appeared to have two classes of binding sites in BSA binding with cephalosporins. The number of primary binding sites appears to be one, secondary binding sites appears to be three. The binding constants were found as follows: BSA-HBAB; $K_1^{obs}$=8.39$\times$$10^4$ $M^{-1}$, $K_2^{obs}$=1.60$\times$$10^4$ $M^{-1}$, BSA-Cefamandole; $K_1^{obs}$=5.44$\times$$10^3$ $M^{-1}$, $K_2^{obs}$=0.74$\times$$10^3$ $M^{-1}$, BSA-Cefotriaxone; $K_1^{obs}$=6.78$\times$$10^3$ $M^{-1}$, $K_2^{obs}$=0.88$\times$$10^3$ $M^{-1}$, BSA-Cefoxitin; $K_1^{obs}$=7.24$\times$$10^3$ $M^{-1}$, $K_2^{obs}$=1.13$\times$$10^3$ $M^{-1}$, BSA-Latamoxef; $K_1^{obs}$=8.87$\times$$10^3$ $M^{-1}$, $K_2^{obs}$=1.92$\times$$10^3$ $M^{-1}$, BSA-Cefotetan; $K_1^{obs}$=15.41$\times$$10^3$ $M^{-1}$, $K_2^{obs}$=2.7$\times$$10^3$ $M^{-1}$.

• 한국식품과학회지
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• 제32권1호
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• pp.42-49
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• 2000

미세캡슐화된 고추올레오레진 capsicum을 사용하여 core material인 올레오레진을 파괴하지 않고, wall material를 제거함으로써 올레오레진 중의 capsaicinoids 함량을 측정하는 방법을 확립하였다. 미세캡슐을 용해할 수 있는 용매로서 dimethyl sulfoxide(DMSO)를 선발하였으며, DMSO에 혼합되는 용매로서 탄수화물을 침전시킬 수 있으면서 올레오레진에 대하여 높은 용해성을 가진 용매인 에탄올을 wall material 침전에 이용하였다. Wall material은 DMSO사용량에 대한 미세캡슐의 사용량의 비율이 $7.5{\sim}10%(w/v)$범위에서 최적이었으며 DMSO 사용량의 8배 이상의 에탄올을 첨가하였을 때 완벽한 추출이 되었다. 또한 동량의 에탄올을 사용하여 추출하였을 때 1회 추출 보다는 2회 반복추출이 완벽하게 capsaicinoids를 용해 할 수 있었다. 가열처리조건은 $55^{\circ}C$, 30분에서 DMSO가 wall materials를 용해시키기에 용이하였고 에탄올 첨가후 capsaicinoids를 추출하기 위한 vortexing time은 40㎐에서 3분 이상의 혼합에서 일정한 값을 보여주었고, 원심분리조건은 21000rpm의 회전속도에서 15분이상이 capsaicinoids함량에 최고치를 나타내었다. 확립된 방법은 고추올레오레진 미세캡슐의 제조 및 저장등의 capsaicinoids의 함량변화측정에 응용이 기대된다.

• Journal of Dental Anesthesia and Pain Medicine
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• 제18권3호
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• pp.143-149
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• 2018

Background: We evaluated the changes in mean arterial pressure (MAP) and heart rate (HR), and the anesthetic and hemostatic effects, after injection of 2% lidocaine containing various concentrations of epinephrine in rats and mice to determine the appropriate concentration of epinephrine in various anesthetic mixtures. Methods: Rats and mice were randomly allocated to experimental groups: 2% lidocaine without epinephrine (L0), 2% lidocaine with epinephrine 1:200,000 (L200), 1:100,000 (L100), and 1:80,000 (L80). Changes in MAP and HR after administration of the anesthetic mixture were evaluated using a physiological recording system in rats. Onset and duration of local anesthesia was evaluated by pricking the hind paw of mice. A spectrophotometric hemoglobin assay was used to quantify the hemostatic effect. Results: MAP increased in response to epinephrine in a dose-dependent manner; it was significantly higher in the L80 group than in the L0 group at 5 min post-administration. The HR was relatively lower in the L0 group than in the L80 group. The time required for onset of action was < 1 min in all evaluation groups. The duration of action and hemostatic effect of the local anesthetic were significantly better in the L200, L100, and L80 groups than in the L0 group. Conclusion: L200 demonstrated relatively stable MAP and HR values with satisfactory efficacy and hemostatic effect. L200 might be a better local anesthetic for dental patients in terms of anesthetic efficacy and safety.

• Journal of Pharmaceutical Investigation
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• 제19권3호
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• pp.163-171
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• 1989

To investigate the protein binding characteristics of cephalothin, the effects of ionic strength, pH and temperature on the binding of cephalothin to bovine serum albumin (BSA) were studied by UV difference spectrophotometric method. With increasing ionic strength at constant PH and temperature, association constant decreased, but the number of binding sites sites was about 2 constantly. It may be deduced that the binding process is not only due to electrostatic forces. And the increased association constant at high ionic strength is explained by conformational changes of BSA from complex to subunits. The pH effect on the affinity of interaction indicated that the binding affinity of drug is higher in the neutral region than in the alkaline region. And, at high pH value, the number of binding sites decreased from 2 to 1 because of the conformational changes of BSA in alkaline region. The decrease in binding affinity of BSA to drug with increasing temperature was characteristic of an exothermic reaction. And the negative sign of ${\Delta}G^{\circ}$ meant that the binding process occurs spontaneously under the experimental conditions. In cephalothin-BSA complex formation, since the net enthalpy change value and entropy change value are positive, it is assumed that hydrophobic bindings are predominant in this binding process.

• 한국작물학회지
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• 제51권1호
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• pp.95-100
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• 2006

Sesamin and sesamolin, antioxidant lipidsoluble lignan compounds, are abundant in sesame (Sesamum indicum L.) seed oil and provide oxidative stability of oil related to sesame quality. The sesamin and sesamolin contents of 403 sesame land races of Korea were determined by HPLC analysis of methanol extract (HPLC value), and their total lignan content was compared with those by using UV-Vis spectrophotometric analysis (UV method) of methanol (UV-MeOH value) and hexane (UV-Hexane value) extracts. HPLC values of total lignan content were strongly associated with UV-Hexane (r=0.705**) and UV-MeOH (r=0.811**) values. The UV values from both the extracts were 3.8-4.7 times higher than those of HPLC values. Lignan content was overestimated by UV method because total compounds in the mixture solution were quantified by absorbing at the same ultraviolet wavelength as in HPLC method. UV method could more rapidly analyze small amount of sample with higher sensitivity of detection than HPLC method. Average contents of lignans in sesame germplasm evaluated in this study were $2.09{\pm}1.02mg/g$ of sesamin, and $1.65{\pm}0.61mg/g$ of sesamolin, respectively, showing significant variation for lignan components. The results showed that UV method for the determination of sesamin and sesamolin could be practically used as a faster and easier method than HPLC by using the regression equations developed in this study.

• Journal of Biosystems Engineering
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• 제27권2호
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• pp.133-142
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• 2002

This is a fundamental study to develop a sensor to detect weeds in paddy field using machine vision adopted spectralphotometric technique in order to use the sensor to spread herbicide selectively. A set of spectral reflectance data was collected from dry and wet soil and leaves of rice and 6 kinds of weed to select desirable wavelengths to classify soil, rice and weeds. Stepwise variable selection method of discriminant analysis was applied to the data set and wavelengths of 680 and 802 m were selected to distinguish plants (including rice and weeds) from dry and wet soil, respectively. And wavelengths of 580 and 680 nm were selected to classify rice and weeds by the same method. Validity of the wavelengths to distinguish the plants from soil was tested by cross-validation test with built discriminant function to prove that all of soil and plants were classified correctly without any failure. Validity of the wavelengths for classification of rice and weeds was tested by the same method and the test resulted that 98% of rice and 83% of weeds were classified correctly. Feasibility of CCD color camera to detect weeds in paddy field was tested with the spectral reflectance data by the same statistical method as above. Central wavelengths of RGB frame of color camera were tried as tile effective wavelengths to distingush plants from soil and weeds from plants. The trial resulted that 100% and 94% of plants in dry soil and wet soil, respectively, were classified correctly by the central wavelength or R frame only, and 95% of rice and 85% of weeds were classified correctly by the central wavelengths of RGB frames. As a result, it was concluded that CCD color camera has good potential to be used to detect weeds in paddy field.

• 공업화학
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• 제25권1호
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• pp.20-26
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• 2014

양이온성 계면활성제인 tetradecyltrimethylammonium bromide (TTAB) 수용액에서 p-할로겐화 페놀유도체들의 가용화현상을 UV/Vis 분광광도법을 이용하여 연구하였다. 가용화현상에 미치는 치환기, 첨가제 및 온도의 효과를 조사하였다. 모든 페놀유도체의 가용화에 대한 ${\Delta}G^o$와 ${\Delta}H^o$ 값은 측정범위 내에서 모두 음의 값을 나타내었으며, ${\Delta}S^o$ 값은 모두 양의 값을 나타내었다. 특히 이들 열역학 함수값들은 할로겐 치환기의 크기, 전기음성도 및 소수성에 크게 영향을 받았다. n-부탄올 첨가제는 모든 페놀유도체의 가용화를 감소시켰으며, NaCl 첨가제는 오히려 가용화를 촉진시켰다. 이런 결과들로부터 페놀유도체들은 치환기의 성질에 따라 미셀 내에서 가용화되는 위치가 서로 다름을 알 수 있었다.