Synthesis of a Novel Fluorescence Switch Conjugated Polymers and Its Discrimination Ability Toward S-Adenosylmethionine
Abstract A novel fluorescence switch was constructed based on poly 3-{[1-(2-hydrazino-2-oxoethyl) piperidin-4-ylidene]methyl} thiophene (PMTH) in the presence of Pb 2+ and S -adenosylmethionine (SAM). The fluorescence of PMTH solution can be efficiently quenched by Pb 2+ ions, resulting in a “fluorescence off” state. Upon the addition of SAM, a strong Pb 2+ chelator, to Pb 2+ -PMTH solution, fluorescence of PMTH can be restored, leading to fluorescence “on”. Based on this fluorescence switch characteristics of PMTH, a new method for recognition and determination of SAM was established. By investigating the fluorescence spectral characteristics of Pb 2+ -PMTH and Pb 2+ -SAM complexes in H 2 O/CH 3 CH 2 OH (4:1, V/V ) solution, we found this method offered advanced sensitivity and selectivity for detecting SAM in the presence of common amino acids and metal ions. Under optimum conditions, the relative fluorescence intensity exhibited a linear relationship with SAM concentration in the range of 1.0 × −8 –2.0 × 10 −6 M. The regression equation was Δ 68.51 + 72.32 C (μith a correlation coefficient r = 0.9982. The limit of detection was 8.72 × 10 −9 M. The method was successfully applied in the detection of SAM in real samples.