New Approach for the Identification of Isobaric and Isomeric Metabolites

The structural elucidation of metabolite molecules is important in many branches of the life sciences. However, the isomeric and isobaric complexity of metabolites makes their identification extremely challenging, and analytical standards are often required to confirm the presence of a particular compound in a sample. We present here an approach to overcome these challenges using high-resolution ion mobility spectrometry in combination with cryogenic vibrational spectroscopy for the rapid separation and identification of metabolite isomers and isobars. Ion mobility can separate isomeric metabolites in tens of milliseconds, and cryogenic IR spectroscopy provides highly structured IR fingerprints for unambiguous molecular identification. Moreover, our approach allows one to identify metabolite isomers automatically by comparing their IR fingerprints with those previously recorded in a database, obviating the need for a recurrent introduction of analytical standards. We demonstrate the principle of this approach by constructing a database composed of IR fingerprints of eight isomeric/isobaric metabolites and use it for the identification of these isomers present in mixtures. Moreover, we show how our fast IR fingerprinting technology allows to probe the IR fingerprints of molecules within just a few seconds as they elute from an LC column. This approach has the potential to greatly improve metabolomics workflows in terms of accuracy, speed, and cost.

Automated summary

The combination of high-resolution ion mobility spectrometry and cryogenic vibrational spectroscopy offers a rapid and efficient method for separating and identifying isomeric and isobaric metabolites. Ion mobility enables the separation of isomers in milliseconds, while cryogenic IR spectroscopy provides clear IR fingerprints for molecular identification. Additionally, our approach allows for automatic identification of metabolite isomers by comparing their IR fingerprints with those in a database, eliminating the need for analytical standards. We demonstrate the principle of this approach by constructing a database of IR fingerprints for eight isomeric/isobaric metabolites and using it for identification in mixtures. Furthermore, our fast IR fingerprinting technology allows for rapid probing of IR fingerprints as molecules elute from an LC column. This approach has great potential to enhance metabolomics workflows in terms of accuracy, speed, and cost.