Autonomous Buffer Preparation

Abstract: Every laboratory involved with liquid chromatography (LC) has to solve the issue of a supply of mobile phase. In the case of reversed-phase liquid chromatography the mobile phase is polar in nature and most commonly aqueous solutions. With a source of distilled water in-house the possibility of creating a mobile phase supply is within reach. A pair of retired LC systems is being repurposed for an automated mobile phase production, and these solutions should have buffering capacity. This thesis will be dedicated to deliver buffer solutions by mixing conjugating acid/base salt stock solutions with distilled water by automating said systems. The automation is made possible by the Python-based Orbit library developed at Department of Chemical Engineering, Lund University. Both experimental setup and programming had to be employed for this endeavour. An signal called "accumulated volume" was experimentally investigated for reliability and accuracy, to be used as a run criteria in automation programming. It was found to be able to deliver volumes within 1.5% difference to target volume (7 ml) at high flowrates (100 ml/min). Programming work spawned new programs with the tasks of keeping track of inventory of a system as well as receiving requests of buffer solution and construct scripts in order to deliver. Conclusively, the current state of the material involved in this project is not a finished automated buffer system. However it is significantly progressed and promising for being an addition to the plethora of tools available for the LC laboratory.