Application of Fully Automated Filtration for Precipitation Polymerizations in Synthesis Robots

Abstract A tailor-made, low-cost filtration module was implemented into a synthesis robot to perform automated sampling during precipitation polymerizations, enabling a direct analysis via gas chromatography (GC). Furthermore, a custom-developed computational workflow was created to automate the processing of raw chromatographic data, leading to an automated evaluation of the reaction progress. For this purpose, a standard septum-piercing needle was modified to fit onto a syringe filter. A rack was designed to hold the sampling vial with a syringe filter attached to it. A spring was utilized to enable a tight fixation of the needle, and a metal block was placed above the rack to ensure safe removal of the needle. To validate the new setup, six precipitation polymerizations were performed. Three of these were purified with the novel automated filtration procedure directly after sampling. The remaining underwent manual filtration of the collected samples at the end of the reaction, enabling a comparison between both approaches. The automated sampling process was highly reproducible and time- as well as work-efficient.