Protocol for Derivatization of Amino Acids Using Dried Fluorescent Dye for In Situ Analysis

This is the authors' abstract. We don't add key points for this paper.

Capillary electrophoresis coupled to a laser-induced fluorescence detector is the ideal approach for in situ analysis of chiral amino acids originating from ocean worlds in our Solar System because of its sample compatibility, high resolution, and enhanced sensitivity. One limitation of this approach is the necessary step of derivatizing amino acids with a fluorescent tag before analysis. The long duration transit time of future missions to ocean worlds dictates that needed reagents must be stored in a way that prevents degradation. In the case of fluorescent dyes, the best approach is to store the dyes as an anhydrous powder. However, the general procedure for derivatization with such dyes involves the use of dye in liquid form as a solution of a known concentration. The efficiency of labeling a sample directly from a dried dye has never been demonstrated. Here, we demonstrate that the use of dried 5-carboxyfluorescein succinimidyl ester (CFSE) dye to label chiral amino acids has a labeling efficiency comparable to previously published labeling methods using the dye in solution.