Spatially resolved in situ determination of reaction progress using microfluidic systems and FT-IR spectroscopy as a tool for biocatalytic process development

Abstract

A concept for the determination of concentrations in microchannels using FT-IR spectroscopy in transmission is presented. The fundamental idea of spatially resolved measurements along several measuring points was implemented in a single-channel microreactor. Compared to existing microreactor setups for the analysis of fast chemical reactions or mixing processes, the presented concept enables longer residence times at appropriate resolution. Once steady-state conditions were reached in the reactor, mid-infrared spectra were collected at different locations. Information throughout the considered conversion range is available, which is of great importance to analyze inhibitory effects, next to the kinetic constants (vmax and KM). Therefore, this technology enables a rapid screening of (bio-)catalysts, substrate specificity and process conditions. In particular, the analysis of real substrates instead of model substrates and the possibility to follow side reactions and follow-up reactions during enzymatic catalysis open a broad field of application.

The application of reaction engineering to biocatalysis

“…Ideally it could be used to reliably determine initial rates at low conversion and likewise have the possibility of conducting high conversion experiments. Recent developments include exciting new ways of collecting data at microscale, [65][66][67][68] although the associated FT-IR and Raman spectroscopy do not yet deliver the required sensitivity. All the methods are summarized in Table 3.…”

Infrared Spectroscopic Imaging Advances as an Analytical Technology for Biomedical Sciences

“…Even with the fastest QCL system available, there are reactions and processes whose time scales will still be elusive to study. The idea of spatially orienting the reaction pathway along with the imaging approach allows one to study the fast reaction and has already been developed in, e.g., microfluidic devices. ,− Such arrangements allow observation of processes happening on the submillisecond scale, i.e., a mixing time of 269 μs. The coupling of accessories with IR imaging systems has been a relative rarity.…”

In situ spatiotemporal characterization and analysis of chemical reactions using an ATR-integrated microfluidic reactor

“…1 This offers the opportunity to obtain a real-time analysis of reactive fluid media. Microfluidics exhibits advantages such as enhanced mass and heat transfer, reduced reagent consumption and advanced fluid control, 2,3 while the incorporation of spectroscopy tools allows researchers to efficiently analyse chemical reactions. 4,5 In recent years, in situ monitoring of chemical reactions has seen significant advances in obtaining information regarding kinetic rate orders, rate constants and reaction mechanisms.…”