• Title/Summary/Keyword: ion concentration

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Relationship Between the Groundwater Resistivity and NaCl Equivalent Salinity in Western and Southern Coastal Areas, Korea (국내 서.남해 해안지역 지하수의 전기비저항과 등가 NaCl 염분도와의 관계)

  • Hwang, Se-Ho;Park, Kwon-Gyu;Shin, Je-Hyun;Lee, Sang-Kyu
    • Geophysics and Geophysical Exploration
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    • v.10 no.4
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    • pp.361-368
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    • 2007
  • In this paper, we suggested the relationship between resistivity of coastal groundwater and NaCl equivalent salinity for the quantitative interpretation the results of surface/borehole resistivity and electromagnetic data. 38 groundwater samples having electrical conductivity higher than about 1,000 ${\mu}S/cm$ were analyzed to derive the empirical relationship between groundwater resistivity and NaCl equivalent salinity. We used Schlumberger chart GEN-8 to convert ion concentration from hydrochemical analysis to the equivalent NaCl salinity, and the portable meter to measure the in situ electrical conductivity of groundwater samples. From the hydrochemical analysis, relationship between the groundwater resistivity $(R_w)$ and equivalent NaCl salinity (Eq_NaCl) is expressed as Eq_NaCl=$5935.3551{\times}R_w^{-1.0993}$, and relationship between the groundwater electrical conductivity (EC) and total dissolved solids (TDS) is expressed as TDS=0.721*EC. We believe these relationships are very useful to assess the seawater intrusion in western and southern coastal area.

Analysis of Methamphetamine and Amphetamine in Oral Fluid of Eleven Drug Abusers (마약남용자 11명의 타액 중 메스암페타민의 분석)

  • Kim, Eun-Mi;Lee, Ju-Seon;Choi, Hye-Young;Choi, Hwa-Kyung;Chung, Hee-Sun
    • YAKHAK HOEJI
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    • v.52 no.6
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    • pp.419-425
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    • 2008
  • A qualitative and quantitative analytical method was developed for detection of methamphetamine (MA) and its main metabolite amphetamine (AM) in oral fluid. Oral fluids of eleven drug abusers were provided by Police, specimens were collected by stimulation with a cotton swab treated with 20 mg of citric acid ($Salivette^{(R)}$; Sarstedt, USA). As the preliminary test, oral fluid samples were screened for amphetamines by Fluorescence Polarization Immunoassay (TDxFLx, Abbott Co.). Extraction for MA was performed using solid-phase extraction (SPE) by $RapidTrace^{TM}$ (Zymark, USA) with mixed mode cation exchange cartridge, CLEAN $SCREEN^{(R)}$ (130 mg/3 ml, UCT) after dilution with phosphate buffer. Samples were evaporated and derivatized by pentafluoropropionic acid anhydride (PFPA). Quantitation of MA and AM was performed by gas chromatography-mass spectrometry (GC-MS) using selective ion monitoring (SIM), the quantitation ions were m/z 204 (MA), 208 (MA-$D_5$), 190 (AM) and 194 (AM-$D_5$). The selectivity, linearity of calibration, limit of detection (LOD) and quantification (LOQ) within- and between day precision, accuracy and recoveries were examined as parts of the method validation. All oral fluid samples gave positive results to immunoassay for MA (cut-off level, 50 ng/ml as d-amphetamine). Concentrations of MA and AM by GC-MS in eleven samples were ranged 104.2${\sim}$4603.3 ng/ml and 32.4${\sim}$268.6 ng/ml, respectively. Extracted calibration curves of MA and AM were linear over the two concentration range of 1${\sim}$100 and 50${\sim}$1000 ng/ml with correlation coefficient of above 0.999. LOQ of MA and AM was 1 and 3 ng/ml, respectively. The intraand inter-day run precisions (CV) for MA and AM were less than 10%, and the accuracies (bias) for MA and AM were also less than 10% at the two different concentrations 5 and 100 ng/ml at low calibration range, 50 and 1000 ng/ml at high calibration range. The absolute recoveries of MA and AM at low and high calibration ranges were more than 82% and 75%, respectively. In this study the qualitative and quantitative analytical method of MA in oral fluid was established. Oral fluid testing may detect drug use in past hours because of its shorter detection window than urine, and be useful in post-accident situations. So oral fluids will be most useful for testing drug abuse in the driving under the influence of drug (DUID) as the alternative specimens of urine.

Construction and Optimization of Selective Membrane Electrodes for Determination of Doxepin Hydrochloride in Pharmaceutical Preparations and Biological Fluids (약의 조제와 생물학적 유체에서 독스핀 하이드로클로라이드의 확인을 위한 선택적 막 전극의 구성과 최적화)

  • El-Tohamy, Maha;Razeq, Sawsan;El-Maamly, Magda;Shalaby, Abdalla
    • Journal of the Korean Chemical Society
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    • v.54 no.2
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    • pp.198-207
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    • 2010
  • The construction and performance characteristics of doxepin hydrochloride selective electrodes were developed. Three types of electrodes: plastic membrane I, coated wire II, and coated graphite rod III were constructed based on the incorporation of doxepin hydrochloride with ammonium reineckate. The influence of membrane composition, kind of plasticizer, pH of the test solution, soaking time, and foreign ions on the electrodes was investigated. The electrodes showed a Nernstain response with a mean slope of 57.41 ${\pm}$ 0.5, 56.22 ${\pm}$ 0.2 and 52.88 ${\pm}$ 0.7 mV at $25^{\circ}C$ for electrode I, II and III respectively, over Doxepin hydrochloride concentration range from $1{\times}10^{-2}-1{\times}10^{-6}M$, $5{\tims}10^{-2}-1{\times}10^{-6}M$ and $1{\times}10^{-3}-5{\times}10^{-6}M$, and with a detection limit $5.0{\times}10^{-7}M$, $6.3{\times}10^{-7}M$ and $2.5{\times}10^{-6}M$ for electrode I, II and III respectively. The constructed electrodes gave average selective precise and usable within the pH range 3 - 7. Interferences from common cations, alkaloids, sugars, amino acids and drug excipients were reported. The results obtained by the proposed electrodes were also applied successfully to the determination of the drug in pharmaceutical preparations and biological fluids.

The Crystal Structure of an Iondine Sorption Complex of Dehydrated Calcium and Silver Exchanged Zeolite A ($Ag^+$이온과 $Ca^{2+}$이온으로 치환한 제올라이트 A를 탈수한 후 요오드를 흡착한 결정구조)

  • Bae, Myung-Nam;Kim, Yang;Kim, Un-Sik
    • Korean Journal of Crystallography
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    • v.6 no.2
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    • pp.118-124
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    • 1995
  • The crystal structure of an iodine sorption complex of vacumm-dehydrated Ag+ and Ca2+ exchanged zeolite A(a=12.174(3)Å) has been determined at 21℃ by single-crystal X-ray diffraction techniques in the cubic space group Pm3m. The crystal was prepared by flow method for three days using exchange solution in solution in which mole ratio of AgNO3 and Ca(NO3)2 was 1:150 with total concentration of 0.05 M. The complex was prepared by dehydration at 360℃ and 2×10-6 Torr for 2 days, followed by exposure to about 14.3 Torr of iodine vaporat 80℃ for 24 hours. Full-matrix least-squares refinement converged to the final error indices of R1=0.082, R2=0.068 using 122 reflections for which I > 3σ(I). Two Ag+ ions, 1.1 Ag+ ions, and 4.45 Ca2+ ions per unit cell are located on three different three-fold axes associated with 6-ring oxygens. Two Ag+ ions per unit cell are in the large cavity, 1.399(4)Å from the (111) plane of three oxygens. Another 1.1 Ag+ ions are found at opposite sites. Six iodine molecules are sorbed per unit cell. Each I2 molecule approaches a framework oxide ion axially (O-I=3.43(2)Å, I-I=2.92Å, I-I-O;166.1(3)°), by a charge transfer complex interaction. Two Ag+ ions make a close approach to the iodine molecules (Ag-I ; 2.73(2)Å).

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A STUDY ON THE ENAMEL EROSION CAUSED BY ORANGE JUICES (오렌지쥬스의 치아 법랑질 침식효과에 대한 연구)

  • Lee, Chang-Yun;Jung, Tae-Sung;Kim, Shin
    • Journal of the korean academy of Pediatric Dentistry
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    • v.31 no.4
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    • pp.617-623
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    • 2004
  • Acidic drink has been known as a cause of tooth erosion. The purpose of this study is to verify the acid levels of orange juices in market and evaluate the erosion effects on the enamel of deciduous teeth by orange juices in relatively short period of time. With four kinds of orange juice selected from market, pH, buffering capacity and concentration of Ca and P ion were measured. And forty segments of normal enamel of deciduous incisors were divided into four groups and level of erosion was measured by surface hardness test before and after soaking at 50ml of orange juice for 10 minutes. The results of this study showed that the average pH of orange juices was 4.0 and this pH value was so acidic as to cause the tooth erosion. There were differences in small quantity for each group of teeth, however, the result was statistically so significant that orange juices can cause enamel erosion in relatively short period of time.

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Organotitanium Chemistry (IV). The Molecular and Electronic Structure of $TiCl(OC_6H_5)_3{\cdot}C_6H_5OH\;and\;Ti(OC_6H_5)_4{\cdot}C_6H_5OH$ (유기티탄 화학 (제4보). $TiCl(OC_6H_5)_3{\cdot}C_6H_5OH\;및\;Ti(OC_6H_5)_4{\cdot}C_6H_5OH$의 분자 및 전자구조)

  • Lee Hoosung;Uh Young Sun;Sohn Youn Soo
    • Journal of the Korean Chemical Society
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    • v.19 no.2
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    • pp.92-97
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    • 1975
  • The molecular and electronic structures of $TiCl(OC_6H_5)_3{\cdot}C_6H_5OH\;and\;Ti(OC_6H_5)_4{\cdot}C_6H_5OH$ have been studied by employing cryoscopic and electronic spectroscopic methods. The cryoscopic data have shown that the dimeric tetraphenoxytitanium(Ⅳ) phenolate in solid undergoes complete dissociation into monomer in solution and also the chlorocomplex starts dissociation around the concentration of 8 m mole/l. Therefore, these two Ti-complexes are pentacoordinated in dilute solution and the local symmetry of the titanium ion in these complexes seems to be trigonalbipyramid. The electronic spectra of $TiCl(OC_6H_5)_3{\cdot}C_6H_5OH$ and $Ti(OC_6H_5)_4{\cdot}C_6H_5OH$ each show two band, systems, one vibration-structural band characteristic of the aromatic ring in the near UV and another visible band at 26.8 kK, 29.6 kK, respectively, which are assigned as a ligand to metal charge transfer band corresponding to $^1A_1''{\to}^1E'\;or\;^1E''$ transition.

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Studies on the Chelating Agent-Impregnated Resins for the Adsorption and Separation of Metal Ions (II). 5,7-Dihalo-8-Hydroxyquimoline(DXHQ)-Impregnated Resins (금속이온 흡착 및 분리를 위한 킬레이트 시약-침윤수지에 관한 연구 (제2보). 5,7-Dihalo-8-Hydroxyquinoline (DXHQ)-침윤수지)

  • Dai Woon Lee;Chul Hun Eum;Yong Soon Chung;Kyu Chang Park
    • Journal of the Korean Chemical Society
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    • v.28 no.6
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    • pp.403-411
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    • 1984
  • Amberlite XAD-7 and XAD-4 resins impregnated with DXHQ (5,7-dihalo-8-hydroxyquinoline) were prepared for the adsorption, separation and recovery of heavy metal ions from aqueous solutions. The characteristics of the impregnated resins, DXHQ (X : Cl, Br, I)-XAD were studied to find out the proper pairs of resin and DXHQ for the adsorption of metal ions. The increasing order of the impregnated amount of DXHQ onto XAD-7 resin was as follows: DCHQ < DBHQ < DIHQ. It was observed from the plot of log $K_d$ vs. pH that the optimum pH range for the adsorption of DIHQ onto XAD-4 resin was from 3.0 to 7.0. The stabilities of the DXHQ-XAD resins were investigated by measuring the amount of DXHQ remained on the XAD resin after shaking the DXHQ-XAD resins in various solutions of pH ranging from 2 to 12 and hydrochloric acid solutions. The impregnated resins were considerably stable in both acidic and neutral solutions. The amount of DIHQ leached from DIHQ-XAD-4 resin by eluting with various HCl solutions (1 ∼ 5M) was negligible, but in the case of XAD-7 resin it increases as the concentration of HCl solution increases. The optimum pH ranges, absorption mole ratio (M : DXHQ) and adsorption capacities (mmol metal per gram of resin) for the adsorption of metal ions onto the DXHQ-XAD resins were determined respectively. The stability of metal ion absorbed by the DXHQ-XAD resins was observed as the following order: M-DCHQ-XAD-7 < M-DBHQ-XAD-7 < M-DIHQ-XAD-7. The adsorbed metal ions were quantitatively recovered by eluting with HCl (0.5 ∼ 5M) and DXHQ-XAD resins could be reused over 5 times without re-impregnation of DXHQ.

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Studies of Magnesium-Eriochrome Black T Complex in Acetonitrile (Acetonitrile에서의 Mg-EBT$^-$ 착물에 관한 연구)

  • Doo Won Park;Won Hyung Choi;Heung Lark Lee
    • Journal of the Korean Chemical Society
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    • v.17 no.4
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    • pp.256-261
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    • 1973
  • Complex formation of magnesium-Eriochrome Black T at constant ionic strength and hydrogen ion concentration have been studied spectrophotometrically in acetonitrile solution. The measured pH values were calibrated with standard buffer solutions by using a glass electrode Ag/0.1M $AgNO_3$ reference electrode couple. The results are as follows;$E_{glass}=716+59.1\;logA_{H+}[mv]$+(in mv. vs. Ag reference electrode for picric acid $-10^{-3}M$ tetramethylammonium picrate buffer), and $E_{glass}=1,193+59.1\;logA_{H+}[mv]$(in mv. vs. Ag reference electrode for 1,3-diphenylguanidine $-3{\times}10^{-3}M $ 1,3-diphenylguanidine perchlorate buffer). The acid dissociation exponent of ligand, $ pK_{H,EBT-}$was found to be 9.1. The conditional formation constants of $MgEBT^{-}$complex by log-ratio method were 3.97 (when m = 2) and 5.02 (when m = 1) as $log K_n$, respectively, for the reaction of $H_mEBT^{(3-m)-} + Mg^{2+} {\leftrightarrow}MgEBT^{-} + mH^{+}$. The present study showed that$MgEBT^{-}$ has the composition of 1:1 which agrees with the result of Schwarzenbach et al. in aqueous solution.

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The Studies on The Tetrazotization of Aromatic Diamines (I). Tetrazotization of p-Phenylenediamine in Hydrochloric Acid and Perchloric Acid (방향족 디아민의 Tetrazo 화에 관한 연구 (제1보). 염산 및과염소산 중에서 p-Phenylenediamine의 Tetrazo 화)

  • Woo Young Lee;Youn Young Lee;Sae Hee Chang
    • Journal of the Korean Chemical Society
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    • v.17 no.4
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    • pp.262-268
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    • 1973
  • p-Phenylenediamine was tetrazotized with sodium nitrite in an excess amount of concentrated hydrochloric acid media at -10$^{\circ}$C. It was also tetrazotized almost completely in 45% perchloric acid media. The two diazo groups in the tetrazonium salt were substituted by halogen, and the degree of tetrazotization reaction was observed by dihalobenzene yielded. The result of the tetrazotization was dependent upon the stability of the tetrazonium salt, and the stability was determined by concentration and quantity of the acid media. In dilute acid media the tetrazonium salt was unstable and completely decomposed. In concentrated acid media, though the tetrazonium salt was stable, tetrazotization reaction was retarded. To harmonize the two opposing tendencies it was advisable to find the optimum acidity of media at which the salt was fairly stable. About $40{\sim}45$% of the acid media was suitable. The fact that the $H^+$ ion behaved as a negative catalyst supported the assumption that the diazotization reaction is primarily a reaction between the free amine and a nitroso group. The reaction of tetrazotization is expressed with respect to the kinetics and mechanism of diazotization.

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Oxygen Ring Formation Reaction of Mono-Oxo-Bridged Binuclear Molybdenum(V) Complex (II). Reaction of $[Mo_2O_3(Phen)_2(NCS)_4]$ with Solvent Water in Water + Co-Solvent Mixtures (한개의 산소다리를 가진 몰리브덴(V) 착물의 산소고리화 반응 (II). 2성분 혼합용매에서 용매물과 $[Mo_2O_3(Phen)_2(NCS)_4]$의 반응)

  • Sang-Oh Oh;Huee-Young Seok
    • Journal of the Korean Chemical Society
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    • v.32 no.3
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    • pp.203-210
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    • 1988
  • Mono-oxo-bridged binuclear molybdenum(V) complex, $[Mo_2O_3(Phen)_2(NCS)_4]$ produces di-oxo-bridged binuclear molybdenum(V) complex, $[Mo_2O_4(Phen)_2(NCS)_2]$ in water + co-solvent, where the co-solvent are acetone, acetonitrile and N,N-dimethylformamide. The rate of conversion of $[Mo_2O_3(Phen)_2(NCS)_4]\;into\;[Mo_2O_4(Phen)_2(NCS)_2]$ has been measured by spectrophotometric method. Temperature was $10^{\circ}C$ to $40^{\circ}C$ and pressure was varied up to 1500 bar. The rate constants are increased with increasing water mole fraction and decreased with increasing concentration of hydrogen ion. The order of oxygen ring formation reaction rate in various cosolvent is as follows, ACT > AN > DMF which is agreed with solvent dielectric constants. The observed negative activation entropy ($[\Delta}S^{\neq}$), activation volume($[\Delta}V^{\neq}$) and activation compressibility coefficient(${\Delta}{\beta}^{\neq}$) values show that the solvent water molecule is strongly attracted to the complex at transition state. From these results, the oxygen ring formation reaction of $[Mo_2O_3(Phen)_2(NCS)_4]$ is believed association mechanism.

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