Titration automated electrochemical

Electrochemical endpoint detection methods provide a number of advantages over classical visual indicators. These methods can be used when visual methods of endpoint detection cannot be employed because of the presence of colored or clouded solutions and in the case of detection of several components in the same solution. They are more precise and accurate. In particular, such methods provide increased sensitivity and are often amenable to automation. Electrochemical methods of endpoint detection are applicable to most oxidation-reduction, acid-base, and precipitation titrations, and to many complex-ation titrations. The only necessary condition is that either the titrant or the species being titrated must give some type of electrochemical response that is indicative of the concentration of the species. 

There are several types of automated KF titrators available from leading companies that supply electrochemical equipment (Metrohm, for example). It should be noted that the mother solutions of these instruments are highly sensitive to side reactions with components of the nonaqueous solution. Hence, the users have to consult the suppliers of the KF mother solutions to ensure that they are compatible with the composition of the studied solution. 

For halogen analysis, the combustion product contains HX (X = Cl, Br, I). HX is trapped in water and titrated with Ag ions by an automated electrochemical process. 

In general, the apparatus for titrimetric analysis is simple in construction and operation. A typical analysis procedure would involve measurement of the amount of sample either by mass or volume, and then addition of the titrant from a burette or micro-syringe. Apart from visual indication, the course of a titration may be followed by electrochemical or photometric means in neither is the equipment required complex. A simple valve voltmeter or conductivity bridge will suffice on the one hand, and a simple spectrophotometer or filter photometer with minor modifications on the other. Varying degrees of automation may be incorporated. 

One advantage of electrochemical endpoint detection is that it lends itself to automation through electronic circuitry. Not only is automation of a titration a labor saving advantage it also eliminates human error and prejudice in the... 

A variety of methods have been used for the analysis of inorganic and organic cations traditional spectroscopic techniques such as colorimetry, wet chemical methods such as gravimetric analysis, turbidimetry, and titrime-try, and electrochemical techniques such as use of an ion-selective electrode and amperometric titrations. Some of these methods suffer from interferences and limited sensitivity they can be labor-intensive and are often difficult to automate. 

Different electrochemical methods have been worked out to indicate the endpoint of argentimetric titrations. They can be used for the analysis of chloride as well as for the other halides. Their application is especially advantageous in mechanized or automated titrators. 

The use of an electrochemical cell with an indicator electrode and a reference electrode to measure the concentration at each stage in the titration facilitates the detection of the end point and the automation of... 

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