A chemical analysis technique that can identify amino acids in liquids could be used to test samples from ocean worlds for signs of microbial life.
Capillary electrophoresis, a process that has been around since the 1980s, searches liquids for the presence of amino acids, which are the building blocks of life as we know it.
The technique involves mixing liquid samples with a liquid reagent, or substance used to either cause or measure a chemical reaction.
Scientists then analyze the mixture under specific conditions by shining a laser across it to reveal individual molecules moving at a variety of speeds.
The molecules are then separated based on the rate at which they respond to electric fields.
Known as laser-induced fluorescence detection, the procedure was used by scientists to search for amino acids in salty water from locations considered difficult for life, such as California’s Mono Lake.
With a high salt and high alkaline content, Mono Lake is a good stand-in for subsurface oceans on Jupiter’s moon Europa and Saturn’s moon Enceladus, and even for saltwater believed to be present on Mars.
Now, scientists at NASA’s Jet Propulsion Laboratory (JPL) is improving the technique specifically for use in the search for life on other worlds.
“Our method improves on previous attempts by increasing the number of amino acids that can be detected in a single run,” said JPL postdoctoral scholar Jessica Creamer.
“Additionally, it allows us to detect these amino acids at very low concentrations, even in highly salty samples, with a very simple ‘mix and analyze’ process,” she noted.
This technique is 10,000 times more sensitive than those currently used by NASA’s Curiosity rover on Mars and by other spacecraft.
It is also simple to automate, meaning it can be done by a robotic explorer.
In the Mono Lake project, scientists successfully found 17 different amino acids, known as “the Signature 17 standard” because they are the most commonly found amino acids.
Amino acids come in two forms that mirror each other, enabling scientists to distinguish those that come from non-living sources from those that come from living organisms.
“One of NASA’s highest-level objectives is the search for life in the universe,” said Peter Willis of JPL, project principal investigator.
“Our best chance of finding life is by using powerful liquid-based analyses like this one on ocean worlds.”
The study’s findings have been published in the journal Analytical Chemistry.