Determination of thioguanine in pharmaceutical preparations by paper substrate room temperature phosphorimetry

A room temperature phosphorimetric (RTP) procedure was used for the determination of 6-thioguanine (6-TG). The method is based on paper substrate room temperature phosphorimetry (PS-RTP) using indium sulfate, In2(SO4)3 as a heavy atom perturber. Various factors affecting the room temperature phosphorescence of 6-TG are discussed. The linear dynamic range for 6-TG is from 3.3 to 334.3 ng per spot with a detection limit of 4.6 ng per spot and a relative standard deviation (RSD) of 2.38%. The recovery of standard 6-TG added to commercial tablets is in the range 96.39-98.44%. The method is simple, rapid and sensitive and can be applied to the analysis of commercial tablets without interference.