SPECTROFLUOROMETRIC DETERMINATION OF 10(-7) M LEVELS OF THIOL COMPOUNDS USING LVER(I)-5,10,15,20-TETRAKIS(4-SULFOPHENYL)PORPHINE COMPLEX

5,10,15,20-Tetrakis(4-sulfophenyl)porphine (TPPS) has a strong fluores cence, while the silver(I) complex [Ag(I)(2)-TPPS] has very little flu orescence, Also, the Ag(I)(2)-TPPS complex easily releases the silver ion from the porphine ring in the presence of thiol compounds such as L-cysteine, glutathione and 2-mercaptoethanol. Based on these results, a highly sensitive spectrofluorimetric determination of 10(-7) M leve ls of thiol compounds was developed, Calibration curves were Linear in the concentration ranges of 0-5 x 10(-7) M for L-cysteine, 0-5 x 10(- 7) M for glutathione and 0-2 x 10(-6) M for 2-mercaptoethanol. Detecti on limits (3 sigma) were 1 x 10(-10) M for L-cysteine, 5 x 10(-11) M f or glutathione and 2 x 10(-11) M for 2-mercaptoethanol. Precisions wer e 1.89% for L-cysteine (2.5 x 10(-7) M), 3.33% for glutathione (2.5 x 10(-7) M) and 2.33% for 2-mercaptoethanol (1.0 x 10(-6) M).