Qualitative determination of latent fingermark glycerides using UPLC-IMS-QToF-MS^E

The composition of the glyceride fraction of latent fingermark lipids is relatively under-investigated due in part to their high structural variability and the limitations of the analytical methods most frequently utilised to investigate fingermark composition (i.e. gas chromatography and infrared spectroscopy). Liquid chromatography presents a more suitable approach for the characterisation of these lipid classes. We present a lipidomics-based approach to characterise glycerides in charged latent fingermarks using data-independent acquisition, using ultra performance liquid chromatography-ion mobility spectroscopy-quadrupole time-of-flight mass spectrometry (UPLC-IMS-QToF-MSE). Di- and triglycerides were identified in fingermark samples through a combination of in silico fragmentation and monitoring for fatty acid neutral losses. Over 100 intact glycerides were identified, with significant diversity in chain length and unsaturation. This method has also been applied to further investigations into the changes in fingermark glyceride composition as a function of time. This method has high potential to gain fundamental knowledge towards understanding the factors affecting fingermark composition, aging and subsequent detection under operational conditions.