EFFECT OF PH AND HEAVY-ATOM ON SOLID-SUBSTRATE ROOM-TEMPERATURE PHOSPHORESCENCE OF PURINE DERIVATIVES

The pH and heavy atom effect on solid-substrate room temperature phosp horescence (SS-RTP) of some purine derivatives were studied in detail. The results showed that the SS-RTP of purines depends on the pH of th e sample solution. The purine derivatives with ketonic oxygen on C6 of purine ring can produce RTP in acidic or neutral solution (pH < 7), t hose with amino substituent on C6 and C2 phosphoresce in the wider pH range (pH 4-11). But purine and thioguanine only phosphoresce in alkal ine solution (pH > 10). For some purine compounds, besides NaI, which is an excellent heavy atom compound for all purine compounds, Tl(I) an d Cd(II) are also have a good enhancement effect on the RTP intensity. The linear dynamic ranges and detection limits under the optimum pH a nd heavy atom were determined. (C) 1997 Elsevier Science S.A.