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- Title
Indirect determination of mercury(II) by using magnetic nanoparticles, CdS quantum dots and mercury(II)-binding aptamers, and quantitation of released CdS by graphite furnace AAS.
- Authors
Sharifi, Arman; Hallaj, Rahman; Bahar, Soleiman; Babamiri, Bahareh
- Abstract
This work describes an aptamer based method for highly sensitive determination of Hg(II). A Hg(II)-binding ssDNA aptamer was linked to silica-coated magnetic nanoparticles (magNPs). Then, a conjugate composed of graphene and CdS quantum dots (Gr-CdS) was linked to the complementary ssDNA. On mixing the two components, a duplex of type magNP-dsNNA-Gr/CdS is generated. If Hg(II) is added, it wills capturing the aptamer, and this leads to the release of Gr/CdS because of the formation of a stable thymine-Hg2+-thymine link. External magnetic force is used to remove the remaining complex. The released graphene-CdS is decomposed by HNO3 and injected into a graphite furnace AAS. The detectable amount of Cd is proportional to the concentration of Hg(II) in the sample. Under the optimal conditions, the method has a linear response in the 2.50 aM to 0.25 nM Hg(II) concentration range, and the detection limit is as low as 7.6 aM (at S/N = 3). It has high selectivity for Hg(II) over other metal ions.
- Subjects
QUANTUM dots; GRAPHITE; MERCURY; APTAMERS; MAGNETIC nanoparticles; MAGNETISM; ANALYSIS of heavy metals; SINGLE-stranded DNA
- Publication
Microchimica Acta, 2020, Vol 187, Issue 1, p1
- ISSN
0026-3672
- Publication type
Article
- DOI
10.1007/s00604-019-4029-x