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A rapid and mild procedure for the preparation of [N‐7‐methyl‐11C] caffeine is described. Gaseous 11C‐methyl iodide wa led into dimethyl sulphoxide (DMSO), containing theophylline (1,3‐dimethylaxanthine) and sodium hydride. Purification of the reaction product was achieved by High Performance Liquid Chromatogrphy (HPLC).

A method for the quantitative determination of 5-fluorouridine (I) in human urine is presented. The analysis involves the isolation of 5-fluorouridine and the internal standard, 5-chlorouridine (II), on immobilized phenylboronic acid; the extract is further purified by mini-column anion exchange chromatography. The resulting methanolic eluate is evaporated to dryness, the residue is dissolved in dimethyl sulfoxide and permethylated using potassium-t-butoxide and methyl iodide. The permethyl derivatives of the nucleosides are reextracted from the reaction mixture and analyzed by GLC on a glass capillary column coupled to a nitrogen-selective detector. Analytical recovery of 5-fluorouridine added to human urine in the 0--1 microgram/ml concentration range was 68 +/- 6% and a linear detector response was obtained up to 1 microgram/ml. The detection limit was found to be 10 ng/ml, using a 1-ml urine sample.