Oligonucleotides are generally synthesized by using a solid-phase synthesis called "phosphoramidite method", in which amidites are used. The following cycle is repeated until the desired chain length is reached: nucleosides fixed on a support >> detritylation >> coupling reaction of amidites >> cap reaction >> oxidation (or sulfidization) reaction. This reaction is performed using the automatic synthesis device. Furthermore, Fujifilm Wako deal with all ancillary reagents that are related to the above-mentioned synthesis of oligonucleotides.