Christen Thomsen Barfoed (June 16, 1815 – April 30, 1899) was a Danish chemist who devised a way to detect monosaccharide sugars in a solution, now known as the Barfoed's test. Barfoed is also credited with having introduced systematic chemical analyses in Danish agricultural sciences.

Based on the paragraph above can we conclude that "Christen Barfoed worked as a chemist when she was elderly."?
It's impossible to say