Online HPLC for Automated Real-Time Chemical Reaction Monitoring

Online HPLC analysis is becoming the gold standard in kinetic analysis and mechanistic elucidation for complex chemical reactions. Traditionally, there have been two methods for collecting samples online: circulating the reaction mixture through a loop before injection, or extracting a specific volume using a sampling tube or capillary. While these methods are effective for uniform liquid solutions, they prove less efficient for heterogeneous reactions, particularly those involving solids, or during active precipitation or crystallization processes.

To address these complex systems, Telescope Innovations Corp. has developed an automatic sampling and delivery system for online HPLC analysis: the DirectInject-LC™. This platform incorporates a rapid mixing and dilution system that allows for precise sample dilution of up to 5000-fold in just 2 minutes between sampling and HPLC injection. DirectInject-LC™ is capable of automatically sampling 20 µL at intervals as frequent as every 3 minutes. Additionally, the platform features a proprietary filtering system that ensures trouble-free repeat injections, and bidirectional communication among modules. This prevents unwanted loss of time and solvents, resulting in enhanced productivity while reducing costs. In this paper, case studies are presented in which DirectInject-LC™ is used to monitor chemical reactions and processes under different matrices, including homogeneous, liquid/liquid, and liquid/solid heterogeneous. Reproducible sampling of these complex matrices is combined with orthogonal spectroscopic analysis software to provide full, comprehensive profiles of chemical reactions and processes in real time.