The Polarographic Determination of Fluvoxamine Maleate

Abstract

In this study, the polarographic behaviour and the optimum polarographic conditions for the determination of fluvoxamine using DC, DP and SIAP techniques are described based on the reduction on the DME. The experiments were conducted in the aqueous supporting electrolyte containing 0.2 M KCI, 20% ethanol (v/v) and 0.2 M buffer solution. Single waves were obtained at various pH values. The limiting currents were decreased and E_1/2 values were linearly shifted to more negative potentials with an increase of pH. The system was irreversible at both the acidic and the basic medium and was controlled by adsorption at pH 4.2 and by diffusion at pH 8.03. The variation of the limiting current against temperature was found to be 1.1 μA°C. Good calibration relations were obtained for DC (direct current), DP (differential pulse) and SIAP (superimposed increasing amplitude pulse) techniques. The determination of fluvoxamine in a pharmaceutical preparation, Faverin® Tablets containing 50 mg of fluvoxamine, were tested. The results were compared to those of UV-spectrophotometric method. In the analysis of a single 50 mg tablet, the relative standard deviation (S_rel) are found to be between ±0.5 and ±1.0 for the techniques employed for filtered and unfiltered solutions. The polarographic techniques used for the determination of fluvoxamine seem to be accurate, rapid and practical. Therefore, the suggested method may be promising in the routine analysis.     

The Polarographic Determination of Tenoxicam in the Pharmaceutical Preparations

Abstract

In this study, the polarographic behaviour and the optimum polarographic conditions for the determination of TNX using DC (direct current), DP (differential pulse), SCAP (superimposed constant amplitude pulse) and SIAP (superimposed increasing amplitude pulse) polarographic techniques are described based on the reduction of enol group of the molecule on the dropping mercury electrode. The experiments were conducted in the aqueous supporting electrolyte solution containing 0.2 M KCl and 0.2 M buffer solution. Single waves were obtained at various pH values. The limiting currents were decreased and E_1/2 values were linearly shifted to more negative potentials with an increase in the pH. The system was irreversible at both the acidic and the basic media and it was adsorptional in the acidic medium and diffusional at pH 10.8. The variation in the limiting current was found to be 0.86 μA/°C. Good relations were obtained for DC, DP, SCAP and SIAP polarographic techniques at pH 10.8. The determination of TNX in pharmaceutical preparations, namely Tilcotil® tablets, containing 20 mg of TNX were tested employing DC, DP, SCAP, SIAP polarographic techniques. The results were compared to those of HPLC and the standard deviations (SD) were found to be in the range of 0.14 and 0.22 for the techniques employed for filtered and unfiltered solutions. The polarographic techniques used for the determination of TNX seem to be accurate, rapid and practical. Therefore, the suggested method may be promising in the routine analysis.

     

Voltammertric Behaviour of Clonixin and its Differential Pulse Polarographic Determination in Tablets

ABSTRACT

Clonixin, a non-steroid analgesic, can be both reduced at the mercury electrode and oxidised at the glassy carbon electrode. The anodic response shows well-defined waves in a pH range between pH 2-12. The polarographic response shows two irreversible waves or peaks in the range between pH 1-6 shifting cathodically when pH increases. Above pH 7.0 all the signals disappeared. The first signal in the dpp mode at pH 1.8 was selected for analytical use. The polarographic     

Polarographic Determination of Subnanogram Quantities of Free Platinum in Reaction Mixture with Dna

Abstract

A simple and rapid differential pulse polarographic assay for measurement of platinum drug binding to DNA is described. The method makes it possible to determine the free (unbound) platinum compound in the presence of DNA or platinum - DNA complex. The method is based on the polarographic catalytic hydrogen current yielded by platinum (II) or (IV) complexes in formaldehyde - hydrazine - sulphuric acid background electrolyte, in which DNA or platinum - DNA complex precipitate. The lower level of analytical utility of this method is c. 1 × 10^?9 M.     

Electrochemical Reduction of Metronidazole and Its Determination in Pharmaceutical Dosage Forms by D.C. Polarography

Abstract

A simple d.c. polarographic method has been developed for the determination of metronidazole in dosages forms. In Robinson - Britton buffer (pH 4.38) and in presence of 1.60 × 10^?3 % Triton X-100, the drug produced a well defined 4-electron polarographic wave followed by another wave of about half the height of the first wave. The current is proportional to the concentration and permits the drug to be determined by d.c. polarography in the concentration range 5.0 × 10^?5 -7.0 × 10^?4 M. Results obtained by the proposed method are in excellent agreement with that provided by the USP-XX method. A rapid, sensitive and accurate polarographic method for the determination of metronidazole in the tablets which are produced locally is proposed.     

A Polarographic Study of Some Aminoanthraquinones

Abstract

Experimental data are given on the influence of the number and the position of the amino groups on the electrochemical reduction potentials of aminoanthraquinones.

The polarographic conditions used for the reduction of some aminoanthraquinones on the dropping mercury electrode are described. The polarograms were obtained in partial aqueous media (the final ratio between dimethylformamide and water is of 20:5) using dimethylformamide as solvent, ammonum acetate as main electrolyte, and Triton X-100 as maxima suppressor. By this method concentrations as low as 0.1 – 0.5 mg/ml could be determined for each aminoanthraquinonic component. Some comparative data are also presented, from which a parallel variation of two features might be drawn: the redox potential and the wavelength of the visible absorption maximum of the investigated aminoanthraquinones. This variation was interpreted as being the result of a similar dependance of these two quantities on the degree of polarization of the carbonyl groups.     

Polarographic assay of Ranitidine Drugs in Pharmaceutical Formulations

Abstract

A simple, accurate and rapid method for the quantitative determination of five ranitidine drugs in pharmaceutical formulations (Tablets and Ampoules) is proposed. The supporting electrolyte was acetic acid-sodium acetate buffer solution (pH 5.2). An excellent linear relationship was obtained between the concentration and current with correlation coefficient 0.9996. Good agreement was obtained between the results with the d.c. polarograhic method and those by the manufacturer's method of assay.     

植酸中无机磷的极谱测定

本文研究了W-Sb-P三元杂多酸的极谱行为,并建立了微量磷的极谱测定方法。该方法有较高的灵敏度,可应用于植酸中无机磷的分析,可以不经分离直接测定。     

Lead Adsorption on a Soil: A Polarographic Study

The adsorption of lead by a non‐contaminated loamy sand soil (Guarda, Portugal) was studied by voltammetric titrations using differential pulse polarography for pH values of 6.0, 6.8 and 7.2 and I of 0.5, 0.1 and 0.01 mol L^?1. After lead or soil additions, residual lead in solution was measured in the presence of the soil particles after an equilibration period, thus with minimum sample manipulation. The characteristics of the surface groups were studied by acid base potentiometric titrations. Lead retention by the soil is influenced both by pH and ionic strength of the medium. From the voltammetric data surface constants and total available binding groups have been estimated according to a complex surface model for the different experimental conditions and the results interpreted in terms of the surface characteristics of the soil and the support medium. Surface binding capacities in the range 1 to 70 mmol Pb kg^?1 were found depending on the pH and the ionic strength. The behavior found is in agreement with what is known in soil chemistry thus supporting the conclusion that voltammetric methods are quite appropriate for determining the extent of interaction between metal ions and soils.     

Electrochemical reduction of secnidazole and its determination in tablets

The electrochemical reduction of secnidazole has been carried out in aqueous solution in the pH range of 2.0–12.0 by DC polarography, AC polarography and cyclic voltammetry. Two well-defined reduction waves appear in acidic media, whereas at higher pHs the two waves overlap. The variation of E_1/2 or E_p and I_lim or I_p with pH was studied. The diffusion-controlled nature of the waves was established and the irreversibility of the electrode process was verified by different criteria. The mechanism of reduction was discussed. A method for the detemination of secnidazole by DC polarography at pH 8.5 which allows quantitation over the 1 × 10⁻⁵ M-4 × 10⁻⁴ M range was proposed and applied to the determination of secnidazole in tablets. The mean recovery was 99.67% and the relative standard deviation was 0.89%. Excipients did not interfere in the determination.     

Polarographic Determination of Inorganic Phosphorus in Phytic Acid

Abstract

A method for the determination of inorganic phosphorus in phytic acid by polarography was developed. The mechanism of Mo/Sb/P polarographic behaviour has been studied. It is one of the most sensitive analytical methods of phosphorus at present. The limit of detection is 8x10^?9 g/ml. This method has been used in the determination of inorganic phosphorus in phytic acid and result is found satisfactory.     

极谱络合吸附催化波测定人发中微量锗的研究

用Ｇｅ（Ⅳ）－邻苯二酚－溴酸钠极谱络合吸附催化波测定人发中微量锗，并对发样的消化处理方法进行了较详细的研究，测定结果令人满意。     

灰化消解-极谱法测定油料中五个重金属元素

建立了灰化消解-极谱法测定油样中镉、铅、铜、镍、钴等5种微量重金属元素的含量.油料样品通过灰化法消解后,用极谱法在乙酸-乙酸盐缓冲溶液和磺基水杨酸-磷酸-氨水体系中测定5种重金属元素的含量.5种微量重金属元素的检出限为1.3×10-4～9.8×10-4 g·L-1,加标回收率为90%～106%,相对标准偏差为0.22%～3.16%.     

极谱免疫法测定人血清补体活性的研究

提出一种极谱免疫法测定人血清补体活性的新方法，利用补体作用下的免疫溶血反应释放出的具有拟过氧化物酶活性的血红蛋白，催化邻苯二胺和Ｈ２Ｏ２的反应，通过酶促产物２，２′－二氨基偶氮苯的极谱检测来确定补体的活性。测定范围为０．１０－１．００ＣＨ５０ｕｎｉｔ／ｍＬ，检出限为０．０８ＣＨ５０ｕｎｉｔ／ｍＬ。灵敏度比分光光度法高１０倍，一次可分析２５份血样，已用于正常人和病人血清中补体活性的测定。     

铁氰化钾-鲁米诺体系后化学发光反应及其分析应用研究-分子印迹-后化学发光法测定双嘧达莫

研究了双嘧达莫在铁氰化钾-鲁米诺化学发光反应体系中的后化学发光反应, 并在研究其反应的动力学性质、化学发光光谱、荧光光谱以及一些相关问题的基础上, 探讨了反应机理; 合成了双嘧达莫的分子印迹聚合物, 以此聚合物为分子识别物质, 利用铁氰化钾-鲁米诺-双嘧达莫后化学发光体系, 建立了测定双嘧达莫的高选择性分子印迹-后化学发光分析方法. 所建方法的线性范围为1.0×10-8-1.0×10-6 g/mL(r=0.999 2), 检出限为3×10-9 g/mL, 相对标准偏差为2.7%(1.0×10-7 g/mL双嘧达莫, n=11).     

Resolution and Trace Determination of Selected Oxyanions in Binary and Ternary Mixtures by Differential Pulse Polarography

Abstract

Resolution and trace determination of selected oxyanions in binary and ternary mixtures were studied by differential pulse polarography (DPP) at the dropping mercury electrode. The applicability of DPP for the simultaneous determination of the investigated oxyanions (TeO^{2- 4}, VO^? ₃, IO^? ₃, IO^? ₄, and BrO^? ₃) in the binary and ternary mixtures was also examined with regard to the dependence of the DP current on various parameters such as pH, pulse amplitude, scan rate and drop time. Statistical analysis is included on t h e observed concentrations for each of the oxyanions in the mixture and compared with that obtained by the calibration curves. Limits of detection and quantitat - ion have been calculated for the DPP determination of binary and ternary mixtures of these lected oxyanions.     

杂多酸示波极谱法测定磷酸根

在pH=1的HCl和25mg/ml抗坏血酸存在的溶液中,磷酸根和钼酸根形成具有极谱活性的磷钼杂多酸。该杂多酸在NH_3-NH_4Cl(pH=9.9)底液中产生—灵敏极谱还原波,其峰电位为-1.12V(vs.SCE)。导数波高与磷酸根浓度在5×10~(-8)～4×10~(-5)mol/L范围内呈良好的线性关系,检测下限2×10~(-8)mol/L。利用反应速度的不同消除了大量硅酸根的干扰。文中对极谱波的性质做了初步研究。     

基于分子印迹识别的化学发光微流控传感器芯片测定双嘧达莫

试验中,以双嘧达莫为模板分子,α-甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,氯仿为溶剂,合成了双嘧达莫分子印迹聚合物。将此聚合物填充在长8 mm,宽1 mm,深0.5 mm的微流控芯片检测池中作为分子识别物质,设计了一种新型的化学发光微流控传感器芯片测定双嘧达莫。双嘧达莫被此聚合物在线吸附并识别,被吸附的双嘧达莫与鲁米诺和铁氰化钾混合溶液反应并导致其化学发光强度增大。该传感器对双嘧达莫响应范围为1.0～20μg·L~(-1),检出限(3σ)为0.5μg·L~(-1),对10μg·L~(-1)双嘧达莫连续平行测定7次,其相对标准偏差为4.6%。     

锗钼杂多酸单扫描极谱法测定枸杞中的微量锗

在ＰＨ８．９的氨性缓冲溶液中,锗钼杂多在示波极谱上,于－１．０５Ｖ（ｖｓ．ＳＣＥ）产生灵敏的吸附波。导数波高与锗 度在６．９＊１０＾－８－５．５＊１０＾－５ｍｏＬ范围内有好的线性关系,检出限为３．５＊１０＾－８ｍｏｌ／Ｌ。用本法测定了中药枸杞中的锗,得到满意的结果。     

扁桃甙水解和极谱行为的研究

通过测定产物间接测定扁桃甙,如用酶修饰电极测定产物氢氰酸和葡萄糖,其检测限均在10~(-5) mol/L。本文首次采用卷积伏安法研究了扁桃甙的水解以及产物苯甲醛的极谱行为,提高了扁桃甙的检测限。 1 仪器与试剂 XJP-821型新极谱仪(长春应用化学研究所、江苏电分析仪器厂),三电极体系,LZ3-100