Thioglycolic acid-capped ZnSe quantum dots as nanoprobe for cobalt(II) and iron(III) via measurement of grey level, UV-vis spectra and dynamic light scattering
Thioglycolic acid-functionalized ZnSe quantum dots (QDs) as a colorimetric nanoprobe were prepared and applied to the determination of cobalt(II) and iron(III). Test strips were obtained by a dipping-drying process. On exposure to Co(II), they undergo a color change from white to brown, and on exposure to Fe(III) from white to pink. The limits of detection (LOD) are 2.6 mg L−1 for Co(II) and 2.2 mg L−1 for Fe(III). Test strips introduce a low-cost, portable, rapid and convenient tool for determination of Co(II) and Fe(III). In addition, two other analytical methods have been studied for detection of Co(II) and Fe(III) at low concentration. The first is UV-vis spectrometry which has a LOD as low as 0.14 mg L−1 for Co(II) (at 412 nm) and 0.12 mg L−1 for Fe(III) (at 400 nm). The second is dynamic light scattering (DLS) with a LOD of 3.0 μg L−1 for Co(II) and 2.5 μg L−1 for Fe(III).
KeywordsTGA-ZnSe QDs Test strip Dipping-drying method Colorimetric determination Grey level On-site examination Color reaction Aggregation of QDs Metal-ligand interaction
This work was supported by Yunnan University’s Research Innovation Fund for Graduate Students (YDY17106) and National Natural Science Foundation of China (Grant No.61761047 and No. 41876055).
Compliance with ethical standards
The author(s) declare that they have no competing interests.
- 1.Gore AH, Gunjal DB, Kokate MR, Sudarsan V, Anbhule PV, Patil SR, Kolekar GB (2012) Highly selective and sensitive recognition of cobalt (II) ions directly in aqueous solution using carboxyl-functionalized CdS QDs as a naked eye colorimetric probe: applications to environmental analysis. ACS Appl Mater Interfaces 4:5217–5226CrossRefGoogle Scholar