Healy P J, Turvey W S, Willats H G
Clin Chim Acta. 1978 Sep 15;88(3):573-6. doi: 10.1016/0009-8981(78)90294-2.
Prolonged contact between silicone-treated stoppers in evacuated tubes and serum was found to interfere in estimation of serum copper concentration using atomic absorption spectrophotometry.