What are the types of polarography?
What are the types of polarography?
Normal polarography has been replaced by different types of pulse polarography (Fig. 6.28), e.g., differential pulse polarography, normal pulse polarography, staircase polarography, and square-wave polarography.
What are the applications of polarography?
Polarography has been used extensively to determine trace metals in pharmaceutical products and to estimate drugs that contain metals as a constituent. The metals examined include antimony, arsenic, cadmium, copper, iron, lead, magnesium, mercury, vanadium and zinc.
What is the basic principle of polarography?
The simple principle of polarography is the study of solutions or of electrode processes by means of electrolysis with two electrodes, one polarizable and one unpolarizable, the former formed by mercury regularly dropping from a capillary tube.
What is polarography technique?
Polarography is a voltammetric technique in which chemical species (ions or molecules) undergo oxidation (lose electrons) or reduction (gain electrons) at the surface of a dropping mercury electrode (DME) at an applied potential.
What are the advantages of polarography?
The major advantages using polarography for inorganic analysis may be summarized: (1) comparatively inexpensive equipment is required, (2) ability of the technique to distinguish between elemental oxidation states (i.e., Cr, As), (3) ability of the technique to establish the chemical form of elements (e.g..
What is polarography PDF?
Definition: Polarography is an electrochemical method of analysis based on the measurement of current flow resulting from the electrolysis of a solution at a polarisable microelectrode as a function of applied voltage.
Which electrode is used in polarography?
dropping mercury electrode
The dropping mercury electrode (DME) is a working electrode made of mercury and used in polarography.
What type of electrode is used in polarography?
mercury
In polarography, mercury is used as a working electrode, because mercury is a liquid metal and thus the electrode can be renewed after each droplet. The working electrode is often a drop suspended from the end of a capillary tube.
Why oxygen is removed in polarography?
Oxygen is an electroreducible species its presence in solution produces a double wave in the range of 0 to – O2 +2H+ + 2e H2O2 H2O2 + 2H+ + 2e 2H2O This wave interferes with the analyte wave. Thus oxygen must be removed by bubbling nitrogen through the solution for five minutes to expel oxygen.
What is the advantage of polarography?
Why mercury is used in polarography?
In polarography, mercury is used as a working electrode, because mercury is a liquid metal and thus the electrode can be renewed after each droplet. The working electrode is often a drop suspended from the end of a capillary tube.
Which gas is removed by polarography?
With d.c. polarography therefore, dissolved oxygen must be removed, but it is not always necessary to do so if a.c. techniques are employed 17.18.
Which statement is true about polarography?
Which statement is true about polarography? Ans: (d) The magnitude of the diffusion current is proportional to concentration of electroactive species Q.
Which electrodes are used in polarography?
The dropping mercury electrode (DME) is a working electrode made of mercury and used in polarography.
What is the use of Polarity analysis in organic chemistry?
Polarography technique is employed in organic chemistry for qualitative and quantitative analysis and structure determinations of organic compounds. Since the organic compounds are insoluble in pure aqueous medium the solvent in which the organic compound and its electrode product is soluble is added to the supporting electrolyte.
What is the theory involved in polarography?
6. The theory involved in polarography is when the working electrode is dipped in the analyte solution containing electro-active species, the following reduction takes place: A (OX) + ne− A (RED) Example: Cu+2 + 2e− Cu The reduced potential is created on the working electrode.
What is the difference between polarography and polarogram?
Polarography is a method of analysis in which the solution to be analyzed is electrolyzed under diffusion controlled condition. The graph of current (generated) as a function of voltage (applied) is known as POLAROGRAM. The technique is known as POLAROGRAPHY.
What is the importance of polarography in medical field?
In medical field polarography is used to analyze natural colouring substance of drugs and pharmaceutical preparations, determining pesticide or herbicide residues in food stuffs, and in the structure determination of many organic compounds.