Smithsonian develops new method to date silkPosted: September 15, 2011
Break out the kimono!
For decades, the art of silk dating was the stuff of old fashioned detective work. But now, scientists at the Smithsonian Museum’s Conservation Institute have created a sure-fire technique based on the natural deterioration of the fabric’s amino acids. And it only takes 20 minutes to perform!
From Smithsonian Science:
“Many things an animal makes are protein based, such as skin and hair. Proteins are made of amino acids,” explains Smithsonian research scientist Mehdi Moini, chief author of a recent paper in the journal Analytical Chemistry announcing the new dating method. “Living creatures build protein by using specific amino acids known commonly as left-handed [L] amino acids. Once an animal dies it can no longer replace the tissues containing left-handed amino acids and the clock starts. As L- changes to D-amino acids [right handed], the protein begins to degrade,” Moini explains. Measuring this ever-changing ratio between left-handed and right-handed (D) amino acids can be used as a scientific clock by which a silk’s age can be estimated. In controlled environments such as museum storage, the decomposition process of silk is relatively uniform, rendering D/L measurement more reliable.
The article “Dating Silk by Capillary Electrophoresis Mass Spectrometry,” appared in the scientific journal Analytical Chemistry, and was authored by Mehdi Moini; Mary Ballard, Smithsonian senior textile conservator; and Museum Conservation Institute intern Kathryn Klauenberg.