STUDY OF A NEW FLUORESCENCE ENHANCEMENT SYSTEM TERBIUM-1, 2, 4, 5-BENZENE TETRACARBONIC ACID AND ITS APPLICATIONS

A fluorescence enhancement phenomenon on adding Gd3+ (or Sc3+ ) to the terbium-1, 2, 4, 5-benzene tetracarbonic acid (BTCA) system was observed and studied in detail.The fluoresence intensities of these systems were 240 times and 95 times greater than those of the systems without gadolinium and scanium. The optimum concentrations were 4. 0 ×10-4mol/L for Gd3+ and 3.0 ×10-4mol/L for Gd and Sc respectively. The optimum pH values were 6. 3 and 6. 5,respectively. The fluorescence intensity was a linear function of the concentration of terbium in the range of 5.0 ×10-8mol/L-3. 0 ×10-5mol/L for system Tb-Gd-BTCA and 7. 0 ×10-8mol/L-1. 0 ×10-5mol/L for system Tb-Sc-BTCA. The detection limits were 2. 0 ×10-10 and 5.0 ×1010 mol/L terbium, respectively. These were used for the determinations of trance amount of terbium in rare earth samples with satisfactory.