Study on the paper substrate room temperature phosphorescence of theobromine, caffeine and theophylline and analytical application

Paper substrate room temperature phosphorescence (RTP) of theobromine (TB), caffeine (CF) and theophylline (TP) were investigated. The method is based on fast speed quantitative filter paper as substrate and KI-NaAc as heavy atom perturber. Various factors affecting their RTP were discussed in detail. Under the optimum experimental conditions, the linear dynamic range, limit of detection (LOD), and relative standard deviation (R.S.D.) were 14.41 similar to 576.54 ng per spot, 1.14 ng per spot, 4.8% for TB, 5.44 similar to 699.08 ng per spot, 0.78 ng per spot, 1.56% for CF, 7.21 similar to 360.34 ng per spot, 1.80 ng per spot, 3.80% for TP, respectively. The first analytical application for the determination of these compounds was developed. The recovery of standard samples added to commercial products chocolate, tea, coffee and aminophylline is in the range 92.80-106.08%. The proposed method was successfully applied to real sample analysis without separation. (C) 2002 Elsevier Science B.V. All rights reserved.