• Archives of Pharmacal Research
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• 제20권1호
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• pp.68-71
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• 1997

Penicillin sensor was prepared by immobilizing penicillinase (Pcase) on $H^{+}$-selective carboxylated poly (vinyl chloride) (PVC-COOH) membrane or cellulose filter membrane. The immobilization techniques are as follows. Pcase was immobilized with GTH on $H^{+}$-selective PVC-COOH membrane or some amount of BSA was dropped on that membrane. Another method to make immobilization is to mix type I Pcase with GTH and drop on a cellulose filter membrane. According to immobilization techniques, there were some differences in response properties of enzyme electrodes, however, all electrodes responded to Pcase-resistant penicillin derivatives. Pcase immobilized on cellulose filter membrane with $H^{+}$-selective PVC membrane eletrode was more stable and more sensitive to penicillinase-resistant penicillin derivatives than any other immobilization techniques.

• 대한화학회지
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• 제38권7호
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• pp.529-532
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• 1994

• Bulletin of the Korean Chemical Society
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• 제23권10호
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• pp.1409-1412
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• 2002

Polymeric membrane electrodes for acetate anion based on meso-(${\alpha}$,${\alpha}$,${\alpha}$,${\alpha}$)-5,10,15,20-tetrakis[2-(penta-fluorophenylurea) phenyl]porphyrin I and similar urea-functionalized porphyrins Ⅱ-Ⅳ as neutral ionophores were prepared. The membrane based on porphyrin I exhibits the best potentiometric properties in pH 6.0 rather than pH 7.0: linear stable response over a wide concentration range (6.0 ${\times}$$10^{-5}$-1.0 ${\times}$$10^{-2}$) with a slope of -59.6 mV/decade and a detection limit of log[CH3CO$O^-$] = -5.32. Selectivity coefficients obtained from the matched potential method (MPM) in pH 6.0 indicate that interferences of hydrophobic anions are very small for the membranes of porphyrins I and II having the strong withdrawing group. The electronic effect of urea-functionalized porphyrins and pH effect of buffer solutions are discussed on the potentiometric response.

• 대한화학회지
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• 제37권8호
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• pp.773-778
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• 1993

Tl$^+$이온 센서로서 크라운 에테르 B15C5와 DB18C6를 중성운반체로 한 PVC 액체막 이온 선택성 전극을 제작하였다. 막용매로는 DOA, NPPE 및 NPOE를 사용하였으며 친유성 염, KTClPB의 농도를 변화시킨 여러가지 조성의 막을 시험하였다. B15C5와 DB18C6 막 전극의 감응전위는 농도범위, 10$^{-1}$∼10$^{-5}$M에서 직선으로 나타났으며 최대 기울기는 전극에 따라서 40∼55 mV/decade였다. 선택계수는 분리용액법으로 결정하였으며 알카리금속 이온, 알칼리토금속 이온 및 일부 전이금속 이온에 대하여 좋은 선택성을 나타냈다. 제작된 액체막 전극은 Ph > 3 에서 안정한 감응전위를 보였다.

• 약학회지
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• 제46권5호
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• pp.320-323
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• 2002

A method for the determination of acidic drug, mefenamic acid and ibuprofen with ion-selective electrode(ISE) using Fe(II)-di-2-pyridyl ketone oxime complex as a counter ion were developed. Benzyl-2-nitrophenyl ether(BNPE) plasticized membrane was more selective and sensitive than the other tested membranes. The acidic drug selective electrode exhibits a linear response for 10$^{-2}$ M 510$^{-5}$ M of acidic drugs, mefenamic acid and ibuprofen with a slope of -55.9 and -56.3 mV/dec. in borate buffer solution (pH 8.9). Potentiometric selectivity measurements revealed negligible interferences from aromatic and aliphatic carboxylic acid salts. The electrodes were found to be useful for the direct determination of mefenamic acid and ibuprofen in pharmaceutical preparations.

• Journal of Biosystems Engineering
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• 제41권2호
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• pp.75-84
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• 2016

Purpose: In-situ water quality monitoring based on ion-selective electrodes (ISEs) is a promising technique because ISEs can be used directly in the medium to be tested, have a compact size, and are inexpensive. However, signal drift can be a major concern with on-line management systems because continuous immersion of the ISEs in water causes electrode degradation, affecting the stability, repeatability, and selectivity over time. In this study, a computer-based nitrate monitoring system including automatic electrode rinsing and calibration was developed to measure the nitrate concentration in water samples in real-time. Methods: The capabilities of two different types of poly(vinyl chloride) membrane-based ISEs, an electrode with a liquid filling and a carbon paste-based solid state electrode, were used in the monitoring system and evaluated on their sensitivities, selectivities, and durabilities. A feasibility test for the continuous detection of nitrate ions in water using the developed system was conducted using water samples obtained from various water sources. Results: Both prepared ISEs were capable of detecting low concentrations of nitrate in solution, i.e., 0.7 mg/L $NO_3-N$. Furthermore, the electrodes have the same order of selectivity for nitrate: $NO_3{^-}{\gg}HCO_3{^-}$ > $Cl^-$ > $H_2PO_4{^-}$ > $SO{_4}^{2-}$, and maintain their sensitivity by > 40 mV/decade over a period of 90 days. Conclusions: The use of an automated ISE-based nitrate measurement system that includes automatic electrode rinsing and two-point normalization proved to be feasible in measuring $NO_3-N$ in water samples obtained from different water sources. A one-to-one relationship between the levels of $NO_3-N$ measured with the ISEs and standard analytical instruments was obtained.

• Bulletin of the Korean Chemical Society
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• 제25권1호
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• pp.59-62
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• 2004

The ammonium ion-selective electrodes ($NH^+_4$-ISEs) based on the tetrahydrofuran(THF)-containing-16-crown-4 derivatives,1,4,6,9,11,14,16,19-tetraoxocycloeicosane ($L^1$) and 5,10,15,20,-tetramethyl-1,4,6,9,11,14,16,19-tetraoxocycloeicosane ($L^2$), were prepared and the electrode characteristics were tested. The conditioned $NH_4^+$-ISEs (E1) based on $L^1$ with TEHP as a plasticising solvent mediator gave best results with near-Nernstian slope of 53.9 mV/decade of activity, detection limit of $10^{-4.9}$ M, and enhanced selectivity coefficients for the $NH^+_4$ ion with respect to an interfering $K^+$ ion (log $K^{pot}_{NH_4^+,K^+}$ = -1.84). This result was compared to other ammonium ionophores reported previously, for example, that of nonactin (log $K^{pot}_{NH_4^+,K^+}$ = -0.92). The proposed electrode showed no significant potential changes in the range of 3.0 < pH < 9.0.

• 공업화학
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• 제24권3호
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• pp.247-252
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• 2013

반응시간을 변화시키면서 poly(ether ether ketone) (PEEK)을 황산과 반응시켜 술폰화도가 다른 sulfonated PEEK (SPEEK)를 합성하였다. 제조한 SPEEK를 탄소전극 표면에 코팅하여 이온선택성 복합탄소전극(ion-selective composite carbon electrode, ISCCE)을 제조하였다. 임피던스 분석을 통해 제조한 ISCCE의 비정전용량과 전기저항을 측정하였다. 술폰화 반응 시간에 따라 SPEEK의 이온교환용량은 1.60~2.57 meq/g으로 측정되었다. 그러나 이온교환용량이 2.5 meq/g 이상에서는 SPEEK가 일부 물에 용해되어 ISCCE 제조에 부적합하였다. ISCCE에 대한 정전용량을 측정한 결과 코팅된 SPEEK의 이온교환용량이 증가함에 따라 정전용량도 증가하였으며 코팅하지 않은 탄소전극에 비해 최대 20%까지 향상되었다. 또한 코팅층의 전기저항은 SPEEK의 이온교환용량이 증가함에 따라 크게 감소하였다. 따라서 SPEEK가 코팅된 ISCCE를 이용하여 기존 축전식 탈염(capacitive deionization, CDI) 공정의 탈염효율을 크게 향상시킬 수 있을 것으로 기대된다.

• Bulletin of the Korean Chemical Society
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• 제31권6호
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• pp.1699-1703
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• 2010

The Schiff base N,N'-bis(pyridin-2-ylmethylene)benzene-1,2-diamine [BPBD] has been synthesized and explored as ionophore for preparing PVC-based membrane sensors selective to the silver ($Ag^+$) ion. Potentiometric investigations indicate high affinity of this receptor for silver ion. The best performance was shown by the membrane of composition (w/w) of ionophore: 1 mg, PVC: 33 mg, o-NPOE: 66 mg and additive were added 50 mol % relative to the ionophore in 1 mL THF. The sensor works well over a wide concentration range $1{\times}10^{-3}$ to $1.0{\times}10^{-7}$ M by pH 6 at room temperature (slope 58.6 mV/dec.) with a response time of 10 seconds and showed good selectivity to silver ion over a number of cations. It could be used successfully for the determination of silver ion content in environmental and waste water samples.

• 약학회지
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• 제47권6호
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• pp.356-360
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• 2003

Nitroso-2-naphthol-3,6-disulfonic acid, disodium salt (NRS) was used as an organic ligand to prepare basic drug-selective polymeric membrane electrode. The sensing membrane of the electrode consited of basic drug-meta1(II)-NRS as an ion-exchanger site in a poly(vinyl chloride) matrix plasticized with 2-nitrophenyl octyl ether (NPOE). The metal ions used were Fe$^{2+}$, Co$^{2+}$, Ni$^{2+}$ and Cu$^{2+}$. The electrodes exhibited fast and wide linear response in the basic drug concentration of 10$^{-5}$ ∼10$^{-3}$ mol/l with a response slope of 50∼60 mV/decade in a buffer solution of pH 4∼8. The electrodes exhibited good selectivity for many basic compounds.mpounds.