• Archives of Pharmacal Research
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• 제23권3호
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• pp.197-201
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• 2000

In an aqueous piperacillin sodium solution, a well-defined single wave or single peak was observed by direct current(DC) polarography or differential pulse polarography(DPP). The peak potential change per pH unit was -54 mV in the phosphate buffer at $18^{\circ}C$, which indicated that protons were involved in the electrochemical reduction of the 2,3-dioxopiperazine moiety of piperacillin sodium with a $H^{+}e^{-}$ ratio of one. Using a phosphate buffer of pH 4.3, the $1.0{times}10^{-7}$ M piperacillin sodium single peak could be determined by DPP with relative standard deviation of 1.6 %(n=3). Piperacillin sodium could be analyzed with-out interference from penicillin G-potassium, which enabled the employment of DPP as a fast and simple technique for monitoring the synthetic process of the antibiotic.

• 대한화학회지
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• 제48권2호
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• pp.137-143
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• 2004

5.0${\times}10^{-2}$ M LiClO4 지지전해질에서 2-mercapto-1-methyl-imidazole(MMI)의 분석을 펄스차이폴라로그래피로 조사하였다. MMI의 분석에서 적절한 조건은 다음과 같다; 초기전위: -0.9 volts, 펄스세기: 0.08 mV, 주사속도: 2 mV/sec. 표준검량곡선은 1.0${\times}10^{-7}{\sim}8.0{\times}10^{-5}$ M 범위에서 좋은 직선성을 보였으며, 검출한계는 (2.2${\pm}0.1){\times}0.1^{-9}$ M이었다. 이 방법으로 첨가제의 방해없이 항갑상선 약제중의 MMI를 정량하는데 응용하였다.

• 분석과학
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• 제8권1호
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• pp.17-23
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• 1995

$5.0{\times}10^{-2}M$ $LiClO_4$ 용액 중에서 펄스차이 폴라그래피로 2-mercapto-1-methyl-imidazole(MMI)의 정량방법을 조사하였다. 분석의 최적 조건은 초기전위 -0.9 volt vs. Ag/AgCl, 펄스높이 80mV, 주사속도 2mV/sec, 중간 크기 수은방울이었다. 검정곡선은 $1.0{\times}10^{-7}M$에서 $8.0{\times}10^{-5}M$ 범위까지 좋은 직선성을 보여 주었으며, 검출한계는 $2.2{\times}10^{-9}M$이었다. 이 방법은 다른 첨가제의 방해 없이 항갑상선 치료제 중의 MMI 정량에 응용할 수 있었다.

• 분석과학
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• 제8권4호
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• pp.691-698
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• 1995

The complexation of platinum and palladium with synthetic polyelectrolytes was studied. The successive and overall stability constants of Pd(II) with PEI and 2PVP were obtained by potentiometric titration. Because of the slow equilibrium time, the potentiometric titrations were performed using the home-made automatic titrator in order to analyze the complexations according to the modified Bjerrum method. The complex formation constant of Pt(IV) with 2PVP, measured by differential pulse polarography, was calculated from the peak currents that were obtained in non-complexing media and in solution containing 2PVP.

• 분석과학
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• 제8권4호
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• pp.655-661
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• 1995

The electrochemical reduction of coumarin derivatives in 0.1M TEAP acetonitrile solution was investigated by the direct current, differential pulse polarography, cyclic voltammetry and controlled potential coulometry. The electrochemical reduction of 7-acetoxy-4-bromomethyl-coumarin(ABMC) was proceeded as an irreversible three steps(-0.58, -1.63 and -2.25 volts) of electrochemical transfer before chemical reaction. The solution color turned to yellow after the carboxyl group was reduced at 2nd step(-1.63 volts vs. Ag-AgCl) and the change in color was independant to the bromo group. Upon the basis of the results on the products analysis and the interpretaton of polarograms, a possible electrochemical reaction mechanism was suggested.

• 대한화학회지
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• 제25권2호
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• pp.103-109
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• 1981

큰 입력지향을 갖는 20개의 sample and hold가 MOSFET으로 switching되는 간편하면서도 비용이 적게드는 analog 기억장치를 제작하였다. 이것은 digital로 3KHz.까지 임의로 조절되는 shift register로 연결되어 있다. 이 장치의 유용성을 보이기 위해 square와 sine파 및 fast-scan voltammetry와 differential pulse polarography의 전류-시간 변화와 같은 전기화학적 실험을 행하였다.

• Bulletin of the Korean Chemical Society
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• 제9권2호
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• pp.77-80
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• 1988

A suituable choice of supporting electrolyte medium for trace level determinations of chromium(VI) by differential pulse polarography is described. A comparative study suggests that sodium borate buffer is superior to ammonium acetate, ammonium tartrate, and especially to NaF which was recently known to be one of the most proper medium for the purpose. With 0.01 M borate, the best combination of high sensitivity, well-defined base line, and freedom from common interferents was attained. With $5.0{\times}10^{-7}$M Cr(VI), tenfold excesses of Cu(II) and Fe(III), and a five hundred-fold excess of $Cl^-$ do not change the peak current by more than about 1%. And the detection limit was $5.0{\times}10^{-8}$M Cr(VI).

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제10권S_3호
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• pp.121-126
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• 2001

The techniques of pulse and cyclic voltammetry were applied to the determination of (E$_{1}$2)$_2$-(E$_{1}$2)$_1$ for two-step electrochemical charge transfers. In addition, a simple amplitude was derived far the dependence of the differential pulse response on (E$_{l}$ 2/)$_1$ and (E$_{1}$2/)$_2$. and the use of peak to peak separation in cyclic voltammetry and differential pulse methods was evaluated. A comparison of the comproportionation constants(Ke) from differential pulse and cyclic voltammetry methods exhibited a good agreement within 5%.

• 분석과학
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• 제9권3호
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• pp.253-261
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• 1996

무기시료 중에 게르마늄의 DPP에 의한 미량 분석법이 연구되었다. 1, 2, 3-트리하이드 록시벤젠이 함유된 과염소산 용액 중에 게르마늄(IV)의 환원 피크가 -0.45V(기준전극 Ag/AgCl)에서 나타났고, 이 피크의 높이는 농도에 직선성을 보였다. 게르마늄 분석시에 감도 및 정밀도에 영향을 주는 인자들이 조사되었고, 최적 조건하에서 검출한계는 1ng/ml였다. 무기물 시료들은 potassium pyrosulfate를 사용한 용융법으로 분해하였다. 게르마늄 검출시 Se(IV), Pb(II), As(III)의 간섭에 대한 조사가 있었고, 이들 간섭은 10M HCl용액 중에서 $CCl_4$로 추출함으로써 해결할 수 있었다. 무기물 시료들 (Pb bf. dust, Cu bf. dust, 편마암, Cu anode slime)중의 게르마늄 함량은 위의 방법으로 정량되었다.

• Bulletin of the Korean Chemical Society
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• 제27권9호
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• pp.1329-1334
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• 2006

The electrochemical reduction of coumarin, 7-acetoxy-4-methyl coumarin (AMC), and 7-acetoxy-4-bromomethyl coumarin (ABMC), in 0.1 M tetraethyl ammonium perchlorate/acetonitrile solution was carried out by direct current, differential pulse polarography, cyclic voltammetry, and controlled potential coulometry. The electrochemical reduction of ABMC was proceeded through three steps of electron transfer coupled with the chemical reactions. The color of solution was changed to yellow when the carbonyl group was reduced during 2nd step (-1.8 volts) and independented with cleavage of bromo group. Highest fluorescence intensity showed when the electrochemical reduction of AMC was controlled at near the potential (-2.3 volts vs. Ag/AgCl).