• Journal of the Korean Chemical Society
• /
• v.29 no.2
• /
• pp.129-136
• /
• 1985

In the atomic absorption spectrometry using an air-acetylene flame, the interferences of Zr, Sn, Al, Sb, $SO_4^{2-},\;VO_3^-,\;and\;SiO_3^{2-}$, on the calcium absorption and the repression of this interference by the addition of cerium have been studied. The interference by Zr, Sn, Al, Sb, $SO_4^{2-},\;VO_3^-,\;and\;SiO_3^{2-}$ existed as the same concentration as calciurn ($3.0 {\times} 10^{-4}$M) in the sample solution are completely released by the addition of cerium twice as much as interfering cation. The interferences by the mixed interfering cations (Zr, Sn, Al and Sb) and by the mixed interfering anions ($SO_4^{2-},\;VO_3^-,\;and\;SiO_3^{2-}$) are larger than by each interfering cation and anion, and the releasing effect by cerium ($1.5 {\times} 10^{-2}$M) is effective up to some degree of the concentration of mixed interfering cations and of mixed interfering anions. The releasing effect by cerium to the mixed solution of interfering cations and anions is applicable to quite wide range of concentration.

• Journal of the Mineralogical Society of Korea
• /
• v.14 no.1
• /
• pp.31-38
• /
• 2001

방해석 결정 성장시 나타나는 미량금속 양이온의 분배현상을 표면침전 및 연속 결정 성장과정을 통하여 관찰하였다. A, B, C 유형의 순수한 방해석이 각각 3가지 다른 초기 농도 즉 0.02, 0.2, 0.4M의 $CaCl_2$.$2H_2$O로부터 형성되었으며 이들의 표면 형태는 합성용액의 조성과 성장 속도에 의해 조절됨을 알 수 있었다. B 유형이 표면형태가 좀더 복잡하지만 A, B 유형은 대체로 단순한{1014}면을 가진 방해석과 유사한 표면형태를 보여준다. 이에 반해 C 유형에서는 {0112}면이 주로관찰되었다. 순수한 방해석 위에 $(Ca, Me)CO_3$층의 대해 {1014}면 3 방향에 대한 전자현미분석 결과 금속이온의 특징적인 분배현상을 알수 있었다. $Mn^{2+}$ /과 $Co^{2+}$ 는 {0112} 에 수직으로 반면 $Sr^{2+ }$ /는 {1014}에 수직 또는 평행한 방향으로 선택적으로 분배되는 현상이 관찰되었다. 합성 방해석 표면 형태에 따른 금속 이온들의 분배 친화도를 Mn$^{2+}$ 이 C 유형>B 유형 >A 유형 그리고 $Co^{2+}$ 은 B 유형 >A 유형 >C 유형이다. 이들중 $Sr^{2+}$는 특히 {1014}면이 잘발달된 A유형에 더 많은 친화도를 갖는 것으로 나타났다.

• Journal of the Korean Chemical Society
• /
• v.39 no.12
• /
• pp.925-931
• /
• 1995

Urea sensors, prepared by immobilizing urease on ammonium-selective membrane electrodes doped with nonactin, can show interference from several ionic species present in blood samples (e.g., sodium, potassium, and endogenous ammonium ions). This interference problem does not arise from the immobilized biocatalytic reaction but rather from the innate response of the base transducer to ionic species in the sample. In this work, the use of calibrators containing adequate amounts of ionic species is examined to reduce errors caused by endogenous ionic interferences with blood urea measurements. Simultaneous measurements of the interfering species with additional sensors and subsequent substractions of these values from the urea electrode signals are also described. It is shown that the use of a potassium-selective electrode with an adequate calibrator system greatly enhances the accuracy of the urea sensor measurements.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2002.02a
• /
• pp.186-191
• /
• 2002

실시간 온라인 계측에 의한 순환식 양액조제 알고리즘을 위해서 이온센서를 사용하였다. 이온센서의 내구성이 약하고 배양액 내에는 이온센서의 정확한 계측의 방해요인인 이온성분들이 포함되어 있기 때문에 매번 정확한 측도 설정을 수행 해줌으로써 계측값의 신뢰도를 높일 수 있었고 이온센서를 이용한 온라인계측의 가능성을 확인할 수 있었다. 그러나 배양액 속에 장시간 넣어둔 상태로 사용하였을 경우 4시간 이상 경과하면 센서에서 나오는 신호가 지속적으로 상승하는 경향을 보였다. 장시간 동안 배양액에 노출되었던 센서는 측도설정이 불가능한 수준으로 일정농도의 용액 내에서 일정한 값을 나타내지 못하고 계측값이 지속적으로 상승하던가 하강하여 한계값 까지 이르렀다. 이러한 이유로 연구용이 아닌 실제 장치에 적용하여 실용화하기 위해서는 내구성이 강하고 계측하고자 하는 이온에 대해 영향을 주는 방해이온 속에서도 정확도를 유지 할 수 있는 센서의 개발이 선행되어야 한다. 또한 정확한 퇴액 성분의 측정을 위해서는 측도 설정이 선행되어야 하는데 계측이 필요할 때마다 측도 설정을 자동으로 해줄 수 있는 자동 측도 설정 모듈의 개발도 수행되어야 할 것으로 사료된다.

• Journal of the Korean Chemical Society
• /
• v.45 no.1
• /
• pp.25-30
• /
• 2001

A selective kinetic fluorimetric method for the determination of trace rhodium(Ⅲ), based on the catalytic effect of rhodium(Ⅲ) on the oxidation of nile blue by periodate have been studied. The effects of pH and concentrations of nile blue, sodium periodate, trioctyl phosphine oxide(TOPO) and temperature were investigated. The calibration curve for rhodium(Ⅲ) ion was linear over the range from 100 ng/mL to 0.1 ng/mL and the detection limit was 0.01 ng/mL under the optimal experimental conditions. Effects of interferences from several cations and anions for the determination of rhodium(Ⅲ) were also investigated.

• Journal of the Korean Chemical Society
• /
• v.36 no.4
• /
• pp.523-535
• /
• 1992

The conformations of hexapeptides, their complexation with alkali cations and the inhibition of the cation transport by 5,5-diphenylhydantoin(DPH) were studied theoretically using ECEPP/2 and MM2 force field. Several low energy conformations of uncomplexed cyclic hexapepides are obtained, and they adopt compact conformations in which most amide hydrogens form intramolecular hydrogen bond to amide carbonyl oxygens. The complexation energy of the peptide with $Na^+$ ion and DPH is -60 kcaal/mol and -18 kcal/mol, respectively. However, no suitable cavity to bind metal cation exists for the local minima of the peptide, and the internal energy of the uncomplexed hexapeptide having cavity is higher than that of the uncomplexed global minimum of this work by 10 kcal/mol. Also, one of the most important amino acid residue to bind DPH is Glycine, and this can explain experimental observation that the replacement of Gly by Sarcosine (N-methyl Glycine) reduce the inhibition ability of the cation transport.

• Journal of the Korean Chemical Society
• /
• v.20 no.4
• /
• pp.280-289
• /
• 1976

The silver selenide electrode has been prepared and its properties as an indicating electrode for silver ion have been investigated. Epoxy resin was used as a filler of silver selenide electrode. Silver metal plate was directly connected with the membrane of the electrode and the silver paste was used as its binder. The sintered electrode was more sensitive and stable than the pressed electrode, and the silver selenide electrode more sensitive than the silver sulfide electrode to silver ion. The linear relationship between the electrode potential and logarithmic concentration of silver ion has been observed down to 10-6 M for the electrode. Several heavy metal ions except mercuric ion did not interfere this linearity, but halide, cyanide, and thiocyanate ions did intensively interfere owing to the formation of silver compounds and complexes. This electrode has been applied to the potentiometric titration for determining halide ion. It is concluded that interferences from ,$CN^-, SCN^-, S^-, I^-, Br^-, Cl^- and Hg^{2+}$ ions are detrimental to the practical use of the electrodes for measuring pAg.

• Journal of the Korean Chemical Society
• /
• v.43 no.4
• /
• pp.430-437
• /
• 1999

The determination of total chlorine residuals in drinking water by flow injection analysis(FIA) with iodometric UV detection was investigated. The pH of the acid stream, the concentration of the iodide ion,the length of the mixing and reaction coils, the injection sample size, and flowrate were optimized as parameters for determining total chlorine residuals by FIA method. lodide was selectively oxidized to iodine by hypochlorite at pH 8.3 Ethylenediamine as masking agent for masking interference ions from the sample was given the best efficency. Calibration curve presented linear range of 0.03-3 mg/L for hypochlorite ion with a correlation coefficient of 0.999 or better. The detection limit was found to be 0.007 mg/L for hypochlorite ion. Under these analytical conditions, total chlorine residuals in several tap water sampled in the city of Jeonju were analyzed.

• Journal of the Korean Chemical Society
• /
• v.29 no.4
• /
• pp.382-389
• /
• 1985

The effect of plasma operational parameters for the determination of rare earth elements(REE) by means of inductively coupled plasma(ICP) spectrometry was investigated. While the increase in the flow rate of carrier gas argon enhanced the sensitivity and lowered the detection limit, significant ionization interferences were observed. The decrease in RF power increased the signal to background ratio. The observation point showing the lowest ionization interference was slightly higher than the position where the spatial profile of the analyte reached the maximum. The detection limits of the spectral lines commonly used for the determination of REE were measured and the spectral lines relatively free from spectral interferences were chosen.

• Journal of the Korean Chemical Society
• /
• v.46 no.5
• /
• pp.407-411
• /
• 2002

A method to determine lead ion in aqueous media using an optical sensor loaded on a fluorescent optode membrane incoporating a metal ion-selective ionophore, a proton-selective chromoionophore and lipophilic anionic sites has been studied. The effects of pH and thickness of membrane on the fluorescence intensity were investigated. The effects of foreign ions such as $Na^+$, $K^+$, $Mn^{2+}$ and $Zn^{2+}$ on the determination of lead ion were also studied. The linear range in the calibration curve for the determination of lead ion was found to be 5.0${\times}10^-7$ to 5.0${\times}$$10^-3$M and the correlation coefficient in this range was -0.99107 under the optimal experimental conditions. The relative standard deviation of the blank signals was 3.0% and the detection limit of lead ion was 5.0${\times}$$10^-9$M.