Thiols adsorption waves

For anions of organic compounds, like thiols (i), derivatives of urea and thiourea (ii) such as barbituric and thiobarbituric acids and their derivatives, as well as for some heterocyclic compounds, the reaction product Hg2(X) is slightly soluble. In such cases the anodic wave is a linear function of concentration only until a concentration is reached, when the surface is covered by Hg2(X) . With a further increase in concentration the limiting current of the anodic wave becomes independent of concentration of X. Such limiting current is controlled by adsorption and is a linear function of the height of the mercury column (h). From the concentration at which the electrode surface is covered by Hg2 (X) it is possible to calculate the surface area covered by the species Hg2(X) . 

Another important area where gold-thiol monolayers might find promising applications is gas- and biosensing. Simple sensors sensitive to certain types of compounds, based on such detection methods as surface plasmon resonance or surface acoustic wave, have been described454,455,531-533. This type of device is usually made of a gold plate coated with a functionalized monolayer. The terminal functional group of such a monolayer is responsible for selective interactions with the analyte, and adsorption of the latter is then detected by the appropriate method. 

---