Meteorites provides a detailed view of outer space

If you’ve ever seen a shooting star, you’ve probably already seen a meteor making its way to Earth. The ones that land here are called meteorites and can be used to peek back in time, into the far corners of outer space or into the oldest building blocks of life. Today, scientists report some of the most detailed analyzes yet of the organic materials of two meteorites. They have identified tens of thousands of molecular “puzzle pieces”, including more oxygen atoms than they expected.

The researchers will present their findings at the American Chemical Society (ACS) spring meeting. ACS Spring 2023 is a hybrid meeting that takes place virtually and in person from March 26-30.

Previously, the team led by Alan Marshall, Ph.D., examined complex mixtures of organic matter found on Earth, including petroleum. But now they turn their attention toward the sky – or things that have fallen from them. Super-resolution mass spectrometry (MS) technology is beginning to reveal new information about the universe and could eventually provide a window into the origin of life itself.

“This analysis gives us an idea of ​​what’s out there, and what we’ll encounter as we go forward as a ‘spacefaring’ species,” says Joseph Fry-Jones, a graduate student presenting the work at the meeting. Marshall and Fry-Jones work at Florida State University and the National High Magnetic Field Laboratory. .

Thousands of meteorites fall to Earth every year, but only a few.Carbon chondrite“the class of space rocks that contain the most organic, or carbon-containing, material. Among the most famous is the “Murchison” meteorite, which fell in Australia in 1969 and has been studied extensively since then. The relatively undiscovered “Aguas Zarcas”, which fell in Costa Rica in 2019, and it blasted through back porches and even a doghouse as pieces fell to the ground.By understanding the organic makeup of these meteorites, researchers can gain information about where and when the rocks formed, and what they encountered on their journey through space.

To understand the complex jumble of particles on meteorites, scientists have turned to MS. This technique divides a sample into small particles, and then essentially determines the mass of each one, represented by a peak shape. By analyzing the set of peaks, or the spectrum, scientists can tell what was in the original sample. But in many cases, the resolution of the spectrometer is only good enough to confirm the presence of a compound that was actually assumed to be present, rather than providing information about unknown components.

This is where cyclotron ion resonance (FT-ICR) MS, also known as “super-resolution” MS, comes in. It can analyze incredibly complex mixtures with very high levels of precision and accuracy. It is particularly suitable for the analysis of mixtures, such as petroleum or complex Organic materials extracted from a meteorite. “With this tool, we really have the precision to look at everything in many types of samples,” says Frye-Jones.

The researchers extracted the organic matter from samples from the Murchison and Aguas Zarcas meteorites, then analyzed it using high-resolution MS. Rather than analyzing only one specific class of molecules at a time, ie Amino acids, they chose to consider all soluble organic matter at once. This provided the team with more than 30,000 peaks of each meteorite for analysis, and more than 60% of them could be given a unique molecular formula. Frye-Jones says these results represent the first analysis of this kind on the Aguas Zarcas meteorite, and the highest-resolution analysis on Murchison. In fact, this team identified nearly twice as many molecular formulas as previously reported for the older meteorite.

Once the data was identified, it was sorted into unique groups based on various properties, such as whether it contained oxygen or sulfur, or whether it had a ring structure or double bonds. They were surprised to find a large amount of oxygen content between the compounds. “Don’t think of oxygen-containing organics as a big part of meteorites,” Marshall explained.

The researchers will then turn their attention to two much more precious samples: a few grams of lunar dust from the Apollo 12 and 14 missions of 1969 and 1971, respectively. These samples date back to before Marshall’s invention of the FT-ICR MS in the early 1970s. The devices have come a long way in the decades since then and are now fully equipped to analyze these powders. The team will soon compare their scores from meteor Analyzes of the data they obtained from lunar samples, hoping to learn more information about where the lunar surface came from. “Was it from meteorites? Solar radiation? We should soon be able to shed some light on that,” says Marshall.