Identification of primary amines in Titan tholins using microchip nonaqueous capillary electrophoresis

- We have optimized nonaqueous detection of primary amines on a microfluidic device.
- We use this ultrasensitive technique to analyze simulated Titan aerosols (tholins).
- Tholins were produced using cold plasma, hot (spark) plasma or UV irradiation.
- Ethylamine was found in all tholins; long-chain amine content varied.
- Targeted functional group analysis via microfluidics can help to understand tholins.

Titan, the moon of Saturn with a thick atmosphere and an active hydrocarbon-based weather cycle, is considered the best target in the solar system for the study of organic chemistry on a planetary scale. Microfluidic devices that employ liquid phase techniques such as capillary electrophoresis with ultrasensitive laser-induced fluorescence detection offer a unique solution for in situ analysis of complex organics on Titan. We previously reported a protocol for nonaqueous microfluidic analysis of primary aliphatic amines in ethanol, and demonstrated separations of short- and long-chain amines down to −20 °C. We have optimized this protocol further, and used it to analyze Titan aerosol analogues (tholins) generated in two separate laboratories under a variety of different conditions. Ethylamine was a major product in all samples, though significant differences in amine content were observed, in particular for long-chain amines (C12-C27). This work validates microfluidic chemical analysis of complex organics with relevance to Titan, and represents a significant first step in understanding tholin composition via targeted functional group analysis.

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