... Exclusion chromatography was carried out in 1.5 x 90 cm columns (Pharmacia Canada Ltd.), monitored by UV absorption at 280 nnl using a Beckman DB-GT recording ... J. Am. Chern. ... Journal of Labelled Compounds and Radiopharmaceuticals 15:10.1002/jlcr.v15:1+, 153-162. ...