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Playing with poison

Associate Professor of Chemistry April Hill worked on the Denver Museum of Nature and Science’s newest exhibit, “The Power of Poison.”

July 28, 2015

Associate Professor of Chemistry April Hill taught volunteers about poisons for a new Denver Museum of Nature and Science exhibit. PHOTO: Sara Hertwig
Associate Professor of Chemistry April Hill taught volunteers about poisons for a new Denver Museum of Nature and Science exhibit. PHOTO: Sara Hertwig

For Associate Professor of Chemistry April Hill, playing with toxins is all in a day’s work. At least it was when she worked on the Denver Museum of Nature and Science’s newest exhibit, “The Power of Poison.”

Hill was among a handful of experts to teach DMNS volunteers about the nature of poison – specifically, the forensic analysis of drugs and poisons – thanks to an invitation by the exhibit’s curator, Nicole Garneau. Hill and Garneau worked together last summer on a project in which they resurrected an ancient beer recipe by examining fermented beverage residue on Mayan pottery.

An expert in analytical chemistry and a certified forensic scientist, Hill knows a thing or two about toxicology, but her work on the latest DMNS exhibit was a learning experience.

“I teach criminalistics (forensic chemistry), so I am familiar with the use of presumptive color tests and instrumental techniques for confirmation,” Hill said. “However, I focus on drugs, as those are far more common than poisons. So some of the historical tests for poisons were somewhat new for me.”

In addition to being filmed presenting, Hill was filmed conducting the Marsh test, a complex methodology developed by chemist James Marsh in 1836 that is used by forensic scientists to detect arsenic. The performing scientist combines hydrochloric acid and zinc to create hydrogen gas. If arsenic is present in an added sample, arsine gas will also be produced.

“The hydrogen and arsine gases flow through a tube into a small glass pipette, where the flammable hydrogen exiting the pipette tip is ignited by a lighter,” Hill said. “Then, as the hydrogen gas burns, the heat converts the arsine gas back to elemental arsenic, which will deposit on a piece of cold glassware held very close to the flame. The result is a shiny layer of metallic arsenic that can be shown to a jury – very convincing!”

The exhibit, which runs through Jan. 10, 2016, explores toxic substances involving animal and plant species, myths, enigmatic poisoning events throughout history and current research on toxicology cases.

Hill’s Marsh test video presentation plays three times hourly during the exhibit’s live stage show.

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