Simultaneous detection of lead (II) and mercury (II) ions using nucleic acid aptamer molecular beacons

• Published in: International journal of environmental analytical chemistry Vol. 101; no. 13; pp. 1922 - 1934
• Main Authors: Lu, Zijing, Xiong, Weiwei, Wang, Peng, Li, Xin, Zhai, Kun, Shi, Rujie, Xiang, Dongshan
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 21.10.2021; Taylor & Francis LLC
• Subjects: Acoustic transponders; aptamer; Aptamers; Bonding strength; Chemical compounds; Detection; Fluorescein; Fluorescence; Fluorophores; Guanine; Ion probes; Lead; Lead (II); Mercury; Mercury (II); Mercury (metal); Nucleic acids; Nucleotides; Probes; Sensors; simultaneous detection
• ISSN: 0306-7319; 1029-0397
• DOI: 10.1080/03067319.2019.1691183

We have developed a fluorescence quantitative analysis method for the simultaneous detection of Hg 2+ and Pb 2+ based on nucleic acid aptamer molecular beacon (MB) probes. In this analytical method, two MB probes for Hg 2+ (P Hg ) and Pb 2+ (P Pb ) were designed. The carboxyl fluorescein (FAM) and tetramethyl-6-carboxyrhodamine (TAMRA) were selected as fluorophores of P Hg and P Pb , Black Hole Quencher 1 (BHQ-1) and Black Hole Quencher 2 (BHQ-2) were selected as organic quenchers, and several continuous nucleotides with guanine (G base) were connected to organic quenchers. The aptamers are put in as a part of stem and loop. In general, the fluorescence of fluorophores was dually quenched by BHQ and G bases, so the fluorescence signals were weak. In the presence of Hg 2+ and Pb 2+ , P Hg and P Pb bonded with them, and the stem-loop structure of MB was destroyed and the fluorescence recovered. Under the optimal conditions, the fluorescence intensity of FAM had a good linear relationship with the concentration of Hg 2+ in the range from 0.7 nmol/L to 84 nmol/L, and that of TAMRA and Pb 2+ in the range from 0.2 nmol/L to 24 nmol/L. The detection limit of Hg 2+ is 0.36 nmol/L and that of Pb 2+ is 0.16 nmol/L (3σ, n = 11). The relative standard deviations (RSD) for determination of Hg 2+ and Pb 2+ were both lower than 5%, the average recoveries of this method in real samples were 96.55-102.78%, which indicated that the method had a high accuracy.