GB661689A - Improvements in or relating to apparatus for carrying out electro chemical analysis - Google Patents

Abstract

661,689. Polarographic apparatus. NATIONAL RESEARCH DEVELOPMENT CORPORATION. March 1, 1949, No. 5634/49. Class 37. Apparatus for carrying out polarographic analysis comprises a cell with a renewable cathode connected through a liquid junction to an external anode and means for establishing the liquid junction with the external anode combined with means for supplying the liquid under examination to the cell. In Fig. 1, taps T4 and T5 are operated to produce test solution from K into cell A and a continuous column of the test solution in tube J and liquid junction side tube L. To remove oxygen a stopper of the capillary electrode I is inserted and nitrogen gas is passed through tube C which reaches to the bottom of cell A; the gas escapes through outlet tube H and tap T8. The capillary electrode I is then inserted, tap T8 is turned to block escape of gas and T5 turned so that excess pressure in the cell A drives some of the test solution up through J and out through tube M and tap T3 thus ensuring that de-oxygenated solution is present in J. Tap T7 is then turned so that nitrogen passes through tube O and over the surface of the test solution and out through the barrel of tap T8. To establish the liquid junction with the external calomel electrode P the stopper in the anode liquid-3.5 M potassium chloride-reservoir O is removed and tap T5 turned so that a column of the dense potassium chloride rises slowly in tube L and forms a liquid junction S. Tap T6 is then turned off and the stopper of O inserted; tap T5 is fully opened and left so until the polargram has been taken. Instructions are given covering emptying and washing the cell A and determining and drop weight or rate of flow of the mercury. A thermostatic water bath B surrounds the cell A. Instead of using a dropping mercury electrode as the renewable cathode, a jet electrode, a stationary renewable electrode or a rotating electrode may be used. It is stated that the apparatus may be adapted for the analysis of very small volumes of a liquid by extending the capillary electrode I into the stem of the cell and utilizing the two-way tap T1 for introducing mercury and forming a small mercury anode at the base of the cell stem.