• Title/Summary/Keyword: 분광 광도법

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Flow Injection Spectrophotometric Determination of Cobalt with 2-(5-Bromo-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino)aniline (2-(5-브로모-2-피리딜아조)-5-(N-프로필-N-슬포프로필아미노)아닐린을 사용하여 흐름주입법에 의한 코발트의 분광광도법적 정량)

  • Kang, Sam Woo;Kim, In Yong;Han, Hong Seok;Lee, Seung Seok
    • Analytical Science and Technology
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    • v.6 no.1
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    • pp.57-63
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    • 1993
  • Spectrophotometric determination of cobalt by flow injection method is described. 2-(5-Bromo-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino) aniline rapidly forms a water-soluble complex with cobalt in $NH_3-NH_4Cl$ buffer solution at pH 10.5. The absorption maxima of this complex is at 545 nm with molar absorptivity of $58000L\;mol^{-1}\;cm^{-1}$. The calibration curve of cobalt is linear over the range of 0.1 to 0.6ppm and the detection limit is 25ppb. The relative standard deviation is ${\pm}0.72%$ for 0.5ppm and the sampling rate is $60samples\;hr^{-1}$. The interfering effect of some cations and anions was investigated. Ni(II), Cu(II), Fe(III) and $CN^-$ interfered severely. The interfering effect of these matallic ions could be decreased by adding $1.0{\times}10^{-3}M$ EDTA solution to the carrier stream.

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Quantitative Analysis of Total Phenolic Content in Apple (사과의 총 페놀함량 정량분석)

  • Whang, Hea-Jeung;Han, Wan-Soo;Yoon, Kwang-Ro
    • Analytical Science and Technology
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    • v.14 no.5
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    • pp.377-383
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    • 2001
  • Total amounts of phenolic compounds of Korean apples were determined by UV-visible spectrphotometry of Folin-Dennis, Prussian-blue and vanillin-HCI, respectively. The analytical data from the method of Folin-Dennis were estimated to be the most reasonable to determine the total amounts of phenolic compounds in Korean apples. It was also confirmed that the amounts of total phenolics could be calculated as chlorogenic acid equivalence, more effectively than that of other phenolic compound equivalence.

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A study on the growth and properties of KTP single crystals ($KTP(KTiOPO_4)$단결정 육성 및 물성 연구)

  • Lee, M.J.;Cha, Y.W.;Jang, J.Y.;Orr, K.K.;Kim, P.C.
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.4 no.1
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    • pp.100-104
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    • 1994
  • KTP seed crystals were grown by the hydrothermal method and the properties of grown crystals were investigated by means of infrared spectrophotometer. The hydrothermal conditions for high growth rates of seed crystals are as follows: temperature ranges, between , $430 and 450^{\circ}C $ ; hydrothermal solvent, 4m KF solution ; temperatures difference, $30<{\triangle}T<65^{\circ}C$ ; filling %, 65% ; growth method, vertical temperature gradient method. Under these conditions, morphologies of the grown KTP single crystals tended to be bounded by (100), (011) and (201) faces and hydroxyl groups were observed in the grown crystals.

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Kinetic Study on the Alkaline Hydrolysis of the Substituted Phenyl N,N-diethyl-P-benzylphosphonamidates (치환 Phenyl N,N-diethyl-P-benzylphosphonamidates의 염기성 가수분해 반응에 대한 속도론적 연구)

  • Shon, Kyoung Hwa;Shin, Gap Cheol
    • Journal of the Korean Chemical Society
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    • v.43 no.1
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    • pp.85-91
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    • 1999
  • The second order rate constants for the hydrolysis of substituted phenyl N,N-diethyl-P-benzylphosphonamidates (2,4-$(NO_2)_2$, 4-$NO_2$, 4-CN, 4-Cl, 4-H)in 20% dioxane-water (v/v) have been determined by UV/Vis spectrophotometric method at various temperatures. The activation parameters (Ea, ${\Delta}H^{\neq}$,${\Delta}S^{\neq}$) were calculated from the rate constants and the reaction constant ($\rho$) was also estimated by Hammett equation. The activation entropies of the title reactions show considerably negative values, this result is not consistent with a dissociative mechanism (EA) in which a positive or a slightly negative value of the entropy of activation should be expected. Further, kinetic evidence for an associative mechanism (AE) was obtained from the linear free energy relationship. By the results of kinetic study for the alkaline hydrolysis of substituted phenyl N,N-diethyl-P-benzylphosphonamidates, it may be concluded that these reactions proceed through an associative mechanism.

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Kinetics and Mechanism of the Hydrolysis of Phenyl N-Benzenesulfonylchloroformimidate Derivatives (Phenyl N-Benzenesulfonylchloroformimidate 誘導體의 加水分解 反應메카니즘과 反應速度論的 硏究)

  • Nack-Do Sung;Ki-Sung Kwon;Tae-Rin Kim
    • Journal of the Korean Chemical Society
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    • v.28 no.5
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    • pp.328-334
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    • 1984
  • A series of phenyl N-benzenesulfonylchloroformimidate derivatives (p-H, p-Cl, p-CH3 & p-OCH3) were prepared and the hydrolysis of these compounds were studied kinetically at various pH by UV spectrophotometry in 1 ; 4 dioxane-water at $25^{\circ}C$. Hammett ${\rho}$ values measured at pH 5.0 (${\rho}$ = -0.45) and pH 10.0 (${\rho}$ = 0.40) indicate that the reaction proceeds via an azocarbonium ion intermediate in the acidic medium, whereas, it involves direct attack by hydroxide ion on the azomethine carbon atom occurs under the basic medium. The formation of stabilized azocarbonium ion species at pH 5.0 is also consistent with the large solvent effect(m = 1.3-1.5 & n = 5.0-5.5). On the basis of these findings, we may concluded that the hydrolysis of phenyl N-benzenesulfonylchloroformimidate derivatives proceeds by $SN_1$ below pH 8.0, however, above pH 10.0, the hydrolysis proceeds through $SN_2$ and in the range of pH 8.0-10.0, these two reactions occur competitively.

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On Board Comparison of Total Hydrogen Ion Concentration (pH) and Total Alkalinity Measurements in Seawater (해수의 총수소이온농도(pH)와 총알칼리도 측정방법에 대한 선상 비교 연구)

  • Kang, Dong-Jin;Tishchenko, Pavel Ya;Kahng, Sung-Hyun
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.14 no.3
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    • pp.205-211
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    • 2011
  • On board comparison of pH and total alkalinity measurement in seawater was carried out during the JES expedition on R/V Roger Revelle in the East Sea using 550 real seawater samples from the surface to the bottom. Spectrophotometry and potentiometry without liquid junction were compared for pH measurement. The pH values of two methods are generally in a good agreement. Spectrophotometry with a pipette provides higher value compare with the potentiometry in the deep layer, where pH values are lower. However, spectrophotometry without a pipette shows same values with potentiometry within their precision range. The pipetting procedure may remove of $CO_2$ in the sample, which causes increase of pH. Potentiometric titration methods using a closed-cell and an open-cell were compared for the total alkalinity measurement. Values from open cell method are smaller by about 5~10 ${\mu}mol\;kg^{-1}$ than those from closed cell method. This may be caused by the bubble formed in the closed cell during the experiment. Although any analytical method compared in this study for the pH or TA measurement can be applied, special attentions should be paid for satisfactory results.

A Sensitive Detection of Actinide Species in Solutions Using a Capillary Cell (모세관 셀을 이용한 수용액 내 악티나이드 화학종의 고감도 검출)

  • Cho, Hye-Ryun;Park, Kyuong-Kyun;Jung, Euo-Chang;Song, Kyu-Seok
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.7 no.2
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    • pp.109-114
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    • 2009
  • Absorption spectra for a quantitative analysis of actinide elements such as U(VI) and Pu(V) were measured by using a liquid waveguide capillary cell (LWCC) which has an optical path length of 1.0 meter. In order to investigate radioactive elements, a LWCC is installed in a glove box and is coupled to a spectrophotometer with optical fibers. Limits of detection (LOD) for the system were determined as 0.74 and 0.35 M with molar absorption coefficients of 8.14${\pm}$0.07 (414 nm) and 17.00${\pm}$0.16 (569 nm) $M^{-1}cm^{-1}$ for U(VI) and Pu(V) ions, respectively. The measured LOD values are about 30 times more sensitive when compared to those achievable by using a conventional quartz cell with an optical path length of 1.0 cm. As an application with an enhanced sensitivity, a quantitative analysis for micromolar concentrations of Pu(V) has been performed to decrease the uncertainty in the formation constant of the Pu(VI)-OH complex.

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Spectrophotometric Determination of Soil Chemical Properties Using Soiltek® KA-P Spectrophotometer (Soiltek KA-P 분광광도계률 사용한 토양 화학적 성질의 분광학적 분석)

  • Hyun, Hae-Nam;Oh, Sang-Sil;Koo, Bon-Jun;Kang, Ho-Jun
    • Korean Journal of Soil Science and Fertilizer
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    • v.33 no.2
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    • pp.127-138
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    • 2000
  • To enable rapid and convenient soil test, new soil analytical methods, which require only one instrument, UV/Vis spectrophotometer, were developed and named "Soiltek KA-P spectrophotometric methods". The Soiltek$^{(R)}$ KA-P spectrophotometric method was compared with standard method of RDA in analytical capability for soil chemical properties. Using the 78 soils collected from upland, paddy, orchard, and vinyl house soils, soil organic matter, exchangeable K, Ca, and Mg. CEC, available $SiO_2$, and nitrate were analyzed by the two methods. The color stability(ratio of the absorbance at elapsed time t to the absorbance at time t=0) of organic matter. Ca, Mg, and available $SiO_2$ decreased to about 2% within one hour. However, that of exchangeable K, CEC, and nitrate remained constant. The results obtained with Soiltek$^{(R)}$ KA-P spectrophotometric method showed highly significant correlation with those measured by the standard method of RDA($R^2$ >0.9501), in which the slopes were near unity of $1.0{\pm}0.05$. The standard deviation values of organic matter, exchangeable K, Ca, and Mg, CEC, available $SiO_2$, and nitrate were apparently lower than ${\pm}1.8gkg^{-1}$, ${\pm}0.05cmol^+kg^{-1}$, ${\pm}0.18cmol^+kg^{-1}$, and ${\pm}0.13cmol^+kg^{-1}$, ${\pm}1.0cmol^+kg^{-1}$, ${\pm}5.0mgkg^{-1}$, and ${\pm}10.0mgkg^{-1}$, respectively. All the measurements showed coefficients of variation of less than 7~17% and were within the confidence level of 95%, which means both the methods are precise. Considering the relative simplicity, low cost, precision and accuracy, the proposed Soiltek$^{(R)}$ KA-P spectrophotometric methods could be recommended as an alternative to standard method.

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Synthesis and characterization of LiCoO2 thin film by sol-gel process (Sol-gel법에 의한 LiCoO2 박막의 합성과 특성평가)

  • Roh, Tae-Ho;Yon, Seog-Joo;Ko, Tae-Seog
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.24 no.3
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    • pp.94-98
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    • 2014
  • $LiCoO_2$ thin film has received diverse attention as cathodes material of thin-film micro-batteries. In this study, $LiCoO_2$ thin films were synthesized on Au substrates by sol-gel spin coating method and an annealing process. Their structures were studied using X-ray diffraction and Raman Spectroscopy. The particle morphologies of these thin films were observed by Scaning electron microscope. From the results of X-ray diffractometry and Raman Spectroscopy analyses, it was found that as-grown films had the structure of spinel (LT-$LiCoO_2$) and layered-Rock-salt (HT-$LiCoO_2$) at $550^{\circ}C$ and $750^{\circ}C$ respectively. The annealed films at $650^{\circ}C$ were presumed to be the mixed state of these two types. Throlugh the scanning electron microscope, It was estimated that the particle size in as-grown films at $750^{\circ}C$, were larger crystilline particle than in those at the other lower temperature and well distributed in the film.

Rates and Mechanism of the Reduction of Vanadium(V) by Benzyl Alcohol in Aqueous Dimethylformamide (DMF 수용매에서 벤질알코올에 의한 바나듐(V)의 환원반응속도와 메카니즘)

  • Chang-Su Kim;Woo-Sik Lee
    • Journal of the Korean Chemical Society
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    • v.32 no.3
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    • pp.179-185
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    • 1988
  • The reaction of VO_2\;^+$ with benzyl alcohol in perchloric acid and aqueous dimethylformamide leads to the formation of $VO^{2+}$ and benzaldehyde. The products, $VO^{2+}$ and benzaldehyde, are identified by infrared spectroscopy and gas chromatography. Kinetic studies on the reaction of VO_2\;^+$ with benzyl alcohol have been carried out using visible spectroscopy. The empirical rate equation can be expressed as $-d[VO_2\;^+]/dt=2\{\\{k_O+k_H[HClO_4]\}\[VO_2\;^+][C_6H_5CH_2OH]$ The rate determining step for the reaction is the process for the formation of $VO^{2+}$ and $C_6H_5CHOH$. The activation parameters are ${\Delta}H^{\neq}=13.32{\pm}1.73\;kcalmol^{-1}$ and ${\Delta}S^{\neq}=-31.02{\pm}0.09\;calmol^{-1}K^{-1}$ for the oxidation of benzyl alcohol in aqueous dimethylformamide.

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