Synthesis of A Novel Fluorescence Switch Conjugated Polymers and Its Discrimination Ability Toward S - Adenosylmethionine

A novel fluorescent switch was constructed based on poly 3-{[1-(2-hydrazino-2-oxoethyl) piperidin-4-ylidene]methyl} thiophene (PMTH) in the presence of Pb super(2+) or S-adenosylmethionine (SAM). The switch turned off in the presence of Pb super(2+) owing to complex effect, and the fluorescence intensity of PMTH solution was efficiently quenched by Pb super(2+) ions. Upon adding SAM to the Pb super(2+) -PMTH solution, which was stronger Pb super(2+) chelators, it could form more stable SAM-Pb super(2+), the Pb super(2+) ion was displaced from PMTH and the fluorescence of PMTH was recovered. By triggering the "turn-on" signal of PMTH, a new discrimination ability toward SAM method for the determination of SAM was established. The effects of the interaction on the fluorescence spectral characteristics of these Pb super(2+)-PMTH and Pb super(2+)-SAM complexes in H sub(2)O-CH sub(3)CH sub(2 )OH(4:1, V/V) solution, suitable reaction conditions and influencing factors were investigated. This method offered good sensitivity and selectivity for detecting SAM in the presence of amino acids and metal ions. Under optimum conditions, the concentration of SAM in the range from 1.0 X 10 super(-8) - 2.0x10 super(-6) mol/L exhibited a linear relationship with the relative fluorescence intensity. The regression equation was Delta I = 68.51 + 72. 32c ( mu mol/L), the correlation coefficient r = 0.9982. The limit of detection was 8.72x10 super(-9) mol/L. The system was successfully applied for detecting SAM in human serum, urine and injection samples.