Fluorescence detection of mercury(II) and lead(II) ions using aptamer/reporter conjugates

• Published in: Talanta (Oxford) Vol. 84; no. 2; pp. 324 - 329
• Main Authors: Lin, Yang-Wei, Liu, Chi-Wei, Chang, Huan-Tsung
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.04.2011; Elsevier
• Subjects: Analytical chemistry; Aptamer; Chemistry; Conjugates; Derivatives; Dimers; Environmental Monitoring - methods; Exact sciences and technology; Excitation; Fluorescence; Interference; Lead - analysis; Lead(II); Mercury - analysis; Mercury(II); Polyguanine; Polythymine; Signal to noise ratio; Spectrometric and optical methods; Spectrometry, Fluorescence - methods; Terbium; Water Pollutants, Chemical - analysis; Polythymine; Polyguanine; Aptamer; Mercury(II); Lead(II); Water; Fold; Fluorescence; Probe; Mixture; Fluorescence spectrometry; Signal; Detection limit; Fluorescence detector; Lead ion; Sample; Interference; Mercury II; Concentration; Soils; Lead II; Terbium; Dimer; Technique; Detection; Signal to noise ratio
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2011.01.016

Two step, fluorescence detection of mercury(II) and lead(II) ions using aptamer/reporter conjugates. We have developed a fluorescence technique for the detection of Hg2+ and Pb2+ ions using polythymine (T33)/benzothiazolium-4-quinolinium dimer derivative (TOTO-3) and polyguanine (G33)/terbium ions (Tb3+) conjugates, respectively. Hg2+ ions induce T33 to form folded structures, leading to increased fluorescence of the T33/TOTO-3 conjugates. Because Pb2+ ions compete with Tb3+ ions to form complexes with G33, the extent of formation of the G33–Tb3+ complexes decreases upon increasing the Pb2+ concentration, leading to decreased fluorescence at 545nm when excited at 290nm. To minimize interference from Hg2+ ions during the detection of Pb2+ ions, we conducted two-step fluorescence measurements; prior to addition of the G33/Tb3+ probe, we recorded the fluorescence of a mixture of the T33/TOTO-3 conjugates and Hg2+ ions. The fluorescence signal obtained was linear with respect to the Hg2+ concentration over the range 25.0–500nM (R2=0.99); for Pb2+ ions, it was linear over the range 3.0–50nM (R2=0.98). The limits of detection (at a signal-to-noise ratio of 3) for Hg2+ and Pb2+ ions were 10.0 and 1.0nM, respectively. Relative to other techniques for the detection of Hg2+ and Pb2+ ions in soil and water samples, our present approach is simpler, faster, and more cost-effective.