金银花中绿原酸的二阶导数差示脉冲极谱法定量研究

建立了中草药金银花中绿原酸的二阶导娄差示脉冲极谱定量分析方法,绿原酸在0.05mol/L硫酸－3mol/L亚硝酸钾－2.5mol/L乙酸钠－95％乙醇（1：1：1：17）的溶液中,于－0.276V(vs.Ag/AgCl)处出现一良好的二阶导数差示脉冲极谱峰,其峰幅值与绿原酸在0.1-0.6mmol/L范围内呈非常显著的线性关系（P＜0.01）,检出限为8.0nmol/L。本法简便、快速、灵敏,结果准确。     

牡丹皮中丹皮酚的二阶导数差示脉冲极谱法定量研究

建立了中草药牡丹皮中丹皮酚的二阶导数差示脉冲极谱定量分析方法。丹皮酚在１ｍｍｏｌ／Ｌ－１ｍｍｏｌ／Ｌ氯化钾－水（１：１：２３）的溶液中,于－１．６．３０Ｖ（ｓ ａｇ／ＡｇＣｌ）处出现一良好的二阶导数差示脉冲极谱峰,其峰幅值与丹皮酚在０．１～０．６ｍｍｏｌ／Ｌ范围内呈非常显著的线性关系（Ｐ〈０．０１）,检测限为９．２ｍｍｏｌ／Ｌ。本法简便、快速、灵敏,且结果准确。     

青霉素钾的二阶导数差示脉冲极谱法定量研究

用二阶导数差示脉冲极谱法定量分析青霉素钾,青霉素钾在水溶液中于-1.350V(vs Ag/AgCl)处有一良好的二阶导数差示脉冲极谱峰,其峰幅值与青霉素钾在50～300ug/mL范围内呈线性关系,检测限为7.4×10~(-9)mol/L。本法简便、快速、灵敏,结果准确。     

大黄中大黄酚的二阶导数差示脉冲极谱法定量研究

建立了中草药大黄中大黄酚的二阶导数差示脉冲极谱定量分析方法。大黄酚在1moL／L氢氧化钾-1moL／L盐酸-甲醇(体积比为1：2：22)的溶液中,于-0．130V(vs．Ag／AgCl)处产生二阶导数差示脉冲极谱峰,大黄酚的浓度在10～80ug／mL范围内与其峰幅值呈良好的线性关系,线性相关系数r=0．9998,检出限为8．6ng／mL。测定结果的相对标准偏差为1．17％(n=8),加标回收率为100．0％。     

盐酸吡哆辛及其制剂的二阶导数差示脉冲极谱法定量研究

建立盐酸吡哆辛及其制剂的二阶导数差示脉冲极谱定量分析方法。盐酸吡哆辛在0.1mol/L氢氧化钠溶液-0.1moL/L磷酸二氢钾溶液-水(体积比为1.2:8.8:990)的混合溶液中,于-0.140V(vs·Ag/AgCl)处出现一良好的二阶导数差示脉冲极谱峰,盐酸吡哆辛浓度在3.6×10~(-4)～9.6×10~(-4)mol/L范围内与其峰幅值呈显著的线性关系(P<0.01),线性相关系数r=0.9997,检出限为9.0nmol/L。     

二阶导数差示脉冲极谱法用于醋酸氟氢可的松的定量研究

用二阶导数差示脉冲极谱法对醋酸氟氢可的松进行了定量分析。在０．００１ｍｏｌ／Ｌ硫酸＋乙醇＋水（１＋２５＋２４）的底液中，醋酸氟氢可的松于－０．３４０Ｖ（ｖｓＡｇ／ＡｇＣｌ）处出现一良好的二阶导数差示脉冲极谱峰，在５～１４０μｇ／ｍＬ范围内，醋酸氟氢可的松的浓度与其二阶导数差示脉冲极谱峰幅值呈线性关系，检测限为０．４ｎｇ／ｍＬ。本法操作简便、快速、灵敏、结果准确。     

磺胺甲恶唑的二阶导数差示脉冲极谱法测定

建立了磺胺甲恶唑的二阶导数差示脉冲极谱定量分析方法,磺胺甲恶唑在１０％ＨＣｌ－（硼酸－氯化钾缓冲溶液）－水（５：５：９０）的底液中,于－１．４５Ｖ（ｖｓ．Ａｇ／ＡｇＣｌ）处出现一良好的二阶导数差示脉冲极谱峰,磺胺甲恶唑浓度与其峰高在０．０８～０．８０ｍｍｏｌ／Ｌ范围内呈线性关系（ｐ〈０．０１）,检测限为８．６ｎｍｏｌ／Ｌ。本法简便、快速、灵敏、结果准确。     

一阶导数差示脉冲极谱法用于扑热息痛的定量分析

一阶导数差示脉冲极谱法用于扑热息痛及其制剂的定量分析，在乙醇－水－２．０×１０＾－＾３ｍｏｌ／ＬＨ２ＳＯ４（１２．５：１１．５：１）的溶液中，于０．２４Ｖ（ｕｓＡｇ／ＡｇＣｌ）处出现良好的一阶导数差示脉冲极谱峰，在３．３×１０＾－＾４～３．３×１０＾－＾３ｍｏｌ／Ｌ范围内，浓度与其一阶导数差示脉冲极谱峰值呈线性关系，检测限为７．８×１０＾－＾８ｍｏｌ／Ｌ。方法简便，快速，灵敏，结果准确。     

定量测定秦皮中秦皮甲素的二阶导数示差脉冲极谱法

建立了中草药秦皮中秦皮甲素的二阶导数示差脉冲极谱定量分析方法。秦皮甲素在乙醇－2mol/L氯化锂－水（体积比2：1：5）的底液中,于－1．703V（vs Ag/AgCl)处出现一良好的二阶导数示差脉冲极谱峰,其峰幅值与秦皮甲素在0．2－1．6mmol/L范围内呈非常显著的线性关系（P＜0．01）,检测下限脒50mmol/L。该法简便、快速、灵敏,结果准确。     

一阶导数差示脉冲极谱法用于甲硝唑的定量研究

本实验运用一阶导数差示脉冲极谱法对甲硝唑及其制剂进行了定量研究。在０．００１ｍｏｌ／Ｌ氯化钾－０．００１ｍｏｌ／Ｌ盐酸－水（１＋０．２＋４８）的底液中，甲硝唑于－０．８００Ｖ（ｖｓ Ａｇ／ＡｇＣｌ）处出现一良好的一阶导数差示脉冲极谱峰，在５０～３００μｇ／ｍＬ范围内，药物浓度与其导数峰幅值呈线关系，检测限为８．０×１０＾－８ｍｏｌ／Ｌ。本法操作简便，快速，灵敏，结果准确。     

维生素C及其制剂的一阶导数差示脉冲极谱法测定

本文建立了维生素Ｃ及其制剂的一阶导数差示脉冲极谱定量分析方法，在水溶液中，维生素Ｃ于－１．１０Ｖ（ｖｓＡｇ／ＡｇＣｌ）处出现一良好的一阶导数差示脉冲极谱峰，在１～１７５μｇ／ｍＬ范围内，维生素Ｃ浓度与其一阶导数差示脉冲极谱峰幅值呈非常显著的线性关系（Ｐ〈０．０１），方法简便，快速，灵敏，结果准确。     

Determination of Entacapone by Differential Pulse Polarography in Pharmaceutical Formulation

Abstract

The electrochemical methods, sampled direct current, and differential pulse polarography, were developed successfully and applied to the routine determination of Entacapone in pharmaceutical formulation. Both methods gave rise to three reduction waves or peaks respectively. The irreversibility and the diffusion‐controlled of the first reduction were confirmed by cyclic voltammetry. The limiting currents are directly proportional to the concentration of entacapone with a correlation coefficient of 0.99. The within‐day coefficients of variation and the day‐to‐day coefficient of variation were less than 3.5% for entacapone and Comtan^®. The percentage recovery for entacapone in tablets is satisfactory for both methods. The method is simple without any pretreatment.     

The Determination of Nitrite and Nitrate Ions by Differential Pulse Polarography

Abstract

A previously reported method for the determination of nitrite ion has been extended to include nitrate ion. Nitrate is reduced to nitrite by a cadmium column and the nitrite ion determined as diphenylnitrosamine. Cadmium interference is removed by pH adjustment and the use of KDTA.     

Determination of Benzoylmetronidazole in Suspension Formulations by Differential Pulse Polarography

Abstract

A rapid, reproducible and accurate method for the determination of benzoylmetronidazole in pharmaceutical suspensions is presented. Differential pulse polarography at a static mercury drop electrode is used for the reduction of the nitro group of benzoylmetronidazole.     

Determination of Codeine,Dionin and Thebaine by Differential Pulse Polarography

Abstract

The method proposed for determining codeine, dionin and thebaine by differential pulse polarography is based on the reduction (in ammoniacal medium) of the nitroderivatives obtained by dissolving the substances in concentrated nitric acid. The values of the reduction potentials range between -0.45 and -0.69 V. Morphine and heroine do not interfere in the determination of the mentioned alkaloids.