Small details become exaggerated when the dust from an insurgent’s bomb settles.Fine chemical compounds left behind near the blast zone — as tiny as the dust from a package of TNT, sometimes invisible to the naked eye — could unlock clues about the explosives used in the blast and who detonated it.Such investigations depend on details as delicate as the moist end of a swab stick.Air Force Academy cadets have spent two years fretting that small stuff. In a laboratory in the academy’s chemistry department, a research team spent the past two years testing a liquid that — when placed on an evidence-collection swab — could help investigators better preserve evidence. They might also be able to test for more substances.The team’s chemical solution — called an ionic liquid — so impressed scientists at the Army Criminal Investigation Laboratory in Atlanta that leaders are considering an extra year of funding for the program, said Jeff Salyards, the laboratory’s chief scientist.If funding is not granted in the next few weeks, Salyards said, he intends to place it as a high priority in next year’s budget.The liquid is meant to solve a vexing problem for Defense Department investigators: How can they swab for more evidence in a war zone, where evidence preservation is key and substances left at a blast site run the gamut of explosives, viruses and even radiological compounds?“We aren’t forensic chemists here,” said Hannah Miller, a research scientist working on the project. “We’re just regular research chemists. So thinking outside the box was a little difficult at first.”

The first step: Understand what wasn’t working.Existing moist swabs aren’t as reliable as investigators prefer, Miller said.One type of liquid on those swabs — called an organic liquid — evaporates relatively quickly, placing an onus on getting samples tested quickly for explosive residue, drug powders or DNA, she said. Organic liquids also are ineffective in picking up certain substances.“If you see a white powder, you don’t know if it’s like a drug, an explosive or it’s just plain sugar,” said Yasmin Sarmiento, 20, a senior cadet at the academy.“It has to be able to pick up a wide range of things,” Miller added.Enter ionic liquids.

The solvent is a special form of salt that remains a liquid at room temperature (meaning it’s easily storable) and dissolves almost everything (meaning it can pick up nearly any substance when used to moisten a swab). Unlikely to evaporate, the liquid is perfectly suited to collect evidence.But ionic liquids aren’t perfect. Different varieties work better with explosives than they do with illicit drugs, and vise versa.It’s also of little use if investigators don’t have a good way to extract and analyze the evidence collected on those swabs.Those problems ahead, the academy team went to work — fine-turning the ionic liquid to overcome several of those obstacles. The team homed in on a one-size-fits-all ionic liquid that can pick up explosives, nerve agents and several types of illicit drugs.Along the way, one cadet found out that TNT forces certain ionic liquids to turn purple.In June, researchers tried their ionic liquid on a DART machine — short for Direct Analysis in Real Time — and managed to measure the mass of compounds picked up on a swab, quickly identifying them.“The chemistry that I’ve learned in the books, how it actually pertains to real world investigations, is definitely an eye opener,” Sarmiento said.The goal is to offer Army investigators a new, improved way of sifting through the dust left after an insurgent’s bomb — a process that goes right down to the type of material (cotton and polyester, to name a few) used to swab a mystery powder.

Up next: Figuring out how to tune that ionic liquid to pick up viruses and radioactive materials.“Everything comes into play in this big puzzle piece of a project,” Miller said.—Contact Jakob Rodgers: 476-1654Twitter @jakobrodgersFacebook Jakob Rodgers

A cadet works with ionic liquids in an Air Force Academy lab. Photo by Air Force Photo