Fingerprinting Biogenic Aldehydes through Pattern Recognition Analyses of Excitation–Emission Matrices

Biogenic carbonyls, especially aldehydes, have previously demonstrated their potential to serve as early diagnostic biomarkers for disease and injury that have not been fully realized owing, in part, to the lack of a rapid and simple point‐of‐care method for aldehyde identification. The ability to determine which carbonyl compound is elevated and not just the total aldehydic load may provide more disease‐ or injury‐specific diagnostic information. Toward this end, a novel fluorophore is presented that is able to form a complex with biogenic carbonyls under catalyst‐free conditions so as to give a fluorescent fingerprint of the resulting hydrazone. The successful identification of bound carbonyls was accomplished with a newly described algorithm that applied principal curvature analysis of excitation–emission matrices to reduce surface features to ellipse representations, followed by a pattern‐matching routine. With this algorithm, carbonyls were identified over a range of concentrations, and mixture components were successfully parsed. Overall, the results presented lay the groundwork for novel implementations of chemometrics to low‐cost, rapid, and simple‐to‐implement point‐of‐care diagnostics. Identifying carbonyl culprits: Using a fluorogenic probe, detection of biogenic carbonyls moves beyond determination of aldehydic load towards fluorescent fingerprinting through analysis of excitation–emission matrices. 3D spectra are discretized to 2D maps that are amenable to pattern matching analysis, which can differentiate carbonyl species in mixtures.