Incorporating silver ions into production

The use of a pair of identical metallic electrodes to establish the equivalence point in amperometric titrations offers the advantages of simplicity of equipment and elimination of the need to prepare and maintain a reference electrode. This type of system has been incorporated into equipment designed for the routine automatic determination of a single species, usually with a coulometric generated reagent. An example of this type of system is an instrument for the automatic determination of chloride in samples of serum, sweat, tissue extracts, pesticides, and food products. Here, the reagent is silver ion coulometrically generated from a silver anode. The indicator system consists of a pair of twin silver electrodes that are maintained at a potential of perhaps 0.1 V. Before the equivalence point in the titration of chloride ion, there is essentially no current because no easily reduced species is present in the solution. Consequently, electron transfer at the cathode is precluded and that... 

The same way was used by Yoon and Kim (2005) for the preparation of 5-(p-methoxyphenyl)thian threnium ion incorporated in a calyx[4]arene. Namely, the ratio of starting materials, methoxycal-ixarene to the thianthrene cation-radical perchorate, was 1 10. The product of such 5-anisylation of thianthrene was further transformed into a calixarene bearing an additional o-phenylene thio-macrocycle. This macrocylization is beyond the scope of this book the original paper by Yoon and Kim (2005) could be recommended for those who interested in. It is worth noting only one practical importance of the calixarene-phenylene thiomacrocycle here It selectively extracts silver(l-l-) by both calixarene and thiomacrocycle. Each molecule of this combined complexon takes up two silver cations, so that extractability achieves 165%. 

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