The review deals with special applications of interdigitated array (IDA) microelectrodes. A high collection efficiency in comparison with RRDE (rotational ring disc electrode) can be used for the determination of species by titration in the diffusion layer of an IDA system. The titrant (iodine, bromine, and hypobromite) is galvanostatically generated on one IDA segment and another segment serves as an amperometric detector with constant potential, which corresponds to the opposite reaction to that of titrant electrochemical generation. The method is simple, sensitive to the species (ammonium, arsenic, thiosulfate, allyl alcohol, iodide) and can also be used in microanalysis.