Efficient derivatization-free monitoring of glycosyltransferase reactions via flow injection analysis-mass spectrometry for rapid sugar analytics.

The widespread application of enzymes in industrial chemical synthesis requires efficient process control to maintain high yields and purity. Flow injection analysis-electrospray ionization-mass spectrometry (FIA-ESI-MS) offers a promising solution for real-time monitoring of these enzymatic processes, particularly when handling challenging compounds like sugars and glycans, which are difficult to quickly analyze using liquid chromatography-mass spectrometry due to their physical properties or the requirement for a derivatization step beforehand. This study compares the performance of FIA-MS with traditional hydrophilic interaction liquid chromatography (HILIC)-ultra high-performance liquid chromatography (UHPLC)-mass spectrometry (MS) setups for the monitoring of the enzymatic synthesis of N-acetyllactosamine (LacNAc) using beta-1,4-galactosyltransferase. Our results show that FIA-MS, without prior chromatographic separation or derivatization, can quickly generate accurate mass spectrometric data within minutes, contrasting with the lengthy separations required by LC-MS methods. The rapid data acquisition of FIA-MS enables effective real-time monitoring and adjustment of the enzymatic reactions. Furthermore, by eliminating the derivatization step, this method offers the possibility of being directly coupled to a continuously operated reactor, thus providing a rapid on-line methodology for glycan synthesis as well.

Comparison of existing laser-induced breakdown thermometry techniques along with a time-resolved breakdown approach.

Temperature is an important parameter for characterizing chemical, physical, and flow processes occurring in combustion environments. Laser-induced breakdown is a process widely used to determine a material's elemental components and its composition, known as laser-induced breakdown spectroscopy (LIBS). The breakdown event, or more specifically the breakdown threshold, for a low-pressure gas strongly depends on density effects emanating in the likelihood for multiphoton and avalanche ionization. In this work, a comparison of thermometry techniques using laser-induced breakdown is made and an approach to perform simultaneous gas-phase thermometry on a shot-to-shot basis and spectroscopy is demonstrated by monitoring the moment in time the thermal plasma develops along the intensity gradient of a laser pulse. Breakdown thresholds are profiled along the height of a lean methane-air and partially combusting rich propane-air McKenna flame, and correlated to radiation and convection-corrected thermocouple readings.