Synthesis routes that can be adapted to large scale synthesis of oligoguanidine compounds such as oligoarginine compounds are described which use a perguanidinylation step to convert a group of -amino groups to the corresponding guanidinyl groups. When the input voltage is above the set voltage, the second-stage converter is controlled to provide both output voltage regulation during normal operation and output current limiting during over-current conditions. After the wafer is entirely withdrawn from the rinsing liquid, the wafer is rotated briefly, to remove any remaining fluid via centrifugal force, without the fluid drying on the wafer.