Sample Preparation for MALDI-TOF Mass Spectrometry of Model Prebiotic Reactions in Simulated Ocean World Environments

The prebiotic potential of ocean worlds such as Europa and Enceladus, while not well constrained, is vital in the search for potential life elsewhere. To better understand this potential, laboratory studies provide experimental insight into the chemical environment(s) of ocean worlds and any constraints to hold prebiotically relevant systems. However, simulated ocean world solutions present a technical challenge for analytical techniques such as mass spectrometry (MS), as the high saline content required for simulating ocean world environments results in ion suppression and reduced sensitivity. Here, we compare three sample preparation techniques, C4 ZipTips, C18 ZipTips, and on-plate washing, for matrix-assisted laser desorption/ionization - time-of-flight (MALDI-TOF) MS of saline solutions similar to environments expected in ocean worlds. We determined that using C18 ZipTips was optimal when paired with 2,5-dihydroxybenzoic acid (DHB) matrix, whereas on-plate desalting was optimal when paired with α-cyano-4-hydroxycinnamic acid (CHCA) matrix. The methodology described here presents simple, low-volume sample preparation strategies for MALDI-TOF MS of model prebiotic reactions in saline solutions.