陸明廉, 徐佩佩, 侯惠民, 陈瑞. 四苯硼酸纳对胺类及含氮杂环类药物的直接电流滴定J. 药学学报, 1965, 12(11): 713-719.
引用本文: 陸明廉, 徐佩佩, 侯惠民, 陈瑞. 四苯硼酸纳对胺类及含氮杂环类药物的直接电流滴定J. 药学学报, 1965, 12(11): 713-719.
LU MING-LIEN, SHYU PEY-PEY, Hou HUI-MING AND CHENG RUI, . DIRECT AMPEROMETRIC TITRATION OF AMINES WITH SODIUM TETRAPHENYLBORATE SOLUTIONJ. Acta Pharmaceutica Sinica, 1965, 12(11): 713-719.
Citation: LU MING-LIEN, SHYU PEY-PEY, Hou HUI-MING AND CHENG RUI, . DIRECT AMPEROMETRIC TITRATION OF AMINES WITH SODIUM TETRAPHENYLBORATE SOLUTIONJ. Acta Pharmaceutica Sinica, 1965, 12(11): 713-719.

四苯硼酸纳对胺类及含氮杂环类药物的直接电流滴定

DIRECT AMPEROMETRIC TITRATION OF AMINES WITH SODIUM TETRAPHENYLBORATE SOLUTION

  • 摘要: 本文研究了用pH8的四苯硼酸钠水溶液对胺类的直接电流滴定法.滴汞为阳极,饱和甘汞为阴极,以3%琼脂的饱和NaCl溶液为盐桥组成电解池.适宜的滴定条件是:外加电压+0.18伏;底液为pH 2-3的HAc-NaAc介质,而以1%HAc更为方便;滴定体积为10-20毫升.可测的浓度范围和胺类的四苯硼酸盐沉淀的溶解度有关:仲胺为1×10-3-2×10-2M;叔胺为6×10-4-2×10-2M;季胺为4×10-4×10-3M;伯胺类不能测定.方法的相对误差因沉淀的溶解度而异,一般在2%以下.滴定时沉淀可不必分离,且无需除氧,操作步骤比较简易.

     

    Abstract: The direct amperometric titration of amines with sodium tetraphenylborate solution based upon anodic depolarization at a dropping mercury electrode by the use of excess TPB titrant, was systematically investigated. The influence of various factors such as pH, volume of titration mixture, quantity of sample in a definite volume to be titrated were studied. Based upon the above observations, a method is proposed as follows: Pipette 0.5-2.0 ml (at a concentration of about 2×10-2M) of samples of various amines into a 50 ml beaker and add 1% HAc to make a volume of about 10-20 ml. The dropping mercury electrode serves as the polarographic anode. Titrate the amines with 0.05 M standard Na-TPB solution (pH 8) at 0.18 V using the saturated NaCl bridge and S.C.E. as reference. After each addition, stir for one minute and allow the solution to obtain a steady current value, then record the galvanometric reading. The end point is graphically plotted with current versus milliliters of titrant; sharp breaks are obtained. The Na-TPB solution was standardized volumetrically by the standard mer- curic solution. Organic bases so determined include aniline, methyl aniline, diethylamine, ephedrine hydrochloride, dimethylaniline, trimethylamine hydrochloride, triethylamine hydrochloride, urotropine, and tetraethylammonium iodide. The relative error of this method is 2%. The more soluble salts of aliphatic primary amines such as methylamine, ethyl- amine, n-butylamine, and even in the case of ephedrine hydrochloride could not be ac- curately titrated. The application of this method to titrate the amines depend largely upon the structure of the amines and the solubility of amine-TPB salts. This method was also successfully applied to titrate the nitrogen containing drugs such as chlopromarzine, cinchophene, quinine sulphate, atropine sulphate, antipyrine, aminopyrine, rivanol, and strychnine.

     

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