Standard affinity applications

In this chapter we shall consider the application of tabulated values of affinities, heats and entropies of reaction to the calculation of equilibrium constants. As we have pointed out already it is much more convenient to consider standard affinities of reaction than equilibrium constants. This is because standard affinities can be added and subtracted in just the same way as stoichiometric equations, so that the standard affinity of a reaction not included in the table is easily calculated. This means, as we shall see, that the only reactions which need to be included are those relating to the formation of compounds from their elements. 

The use of ELISA is broad and it finds applications in many biological laboratories over the last 30 years many tests have been developed and vahdated in different domains such as clinical diagnostics, pharmaceutical research, industrial control or food and feed analytics for instance. Our work has been to redesign the standard ELISA test to fit in a microfluidic system with disposable electrochemical chips. Many applications are foreseen since the biochemical reagents are directly amenable from a conventional microtitre plate to our microfluidic system. For instance, in the last 5 years, we have reported previous works with this concept of microchannel ELISA for the detection of thromboembolic event marker (D-Dimer) [4], hormones (TSH) [18], or vitamin (folic acid) [24], It is expected that similar technical developments in the future may broaden the use of electroanalytical chemistry in the field of clinical tests as has been the case for glucose monitoring. This work also contributes to the novel analytical trend to reduce the volume and time consumption in analytical labs using lab-on-a-chip devices. Not only can an electrophoretic-driven system benefit from the miniaturisation but also affinity assays and in particularly immunoassays with electrochemical detection. 

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