A novel phosphorescence sensor for Co²⁺ ion based on Mn‐doped ZnS quantum dots

Abstract

N-acetyl-L-cysteine-capped Mn-doped ZnS quantum dots (QDs) were prepared by hydrothermal methods. It could emit phosphorescence at 583 nm with the excitation wavelength at 315 nm. The phosphorescence intensity of QDs could be quenched dramatically by increasing the concentration of Co(2+) ion. The novel phosphorescence sensor based on N-acetyl-L-cysteine-capped QDs was developed for detecting Co(2+) ion with a linear dynamic range of 1.25 × 10(-6) -3.25 × 10(-5) m. The limit of detection and RSD were 6.0 × 10(-8) m and 2.3%, respectively. Interference experiments showed excellent selectivity over numerous cations such as alkali, alkaline earth and transitional metal ions. The possible quenching mechanism was also examined by phosphorescence decays. The proposed phosphorescence method was further applied to the trace determination of Co(2+) ion in tap and pond water samples with recoveries of 97.75-103.32%.

Bovine serum albumin‐confined silver nanoclusters as fluorometric probe for detection of biothiols

“…The quenching effect is closely related to the patterns of mercapto. Mercapto of biothiol was mainly present in a protonated pattern in strong acidic media and resulted in a weak quenching effect . In neutral and weak basic media the deprotonated mercapto had strong affinity to the AgNCs and readily caused the fluorescence quenching of BSA–AgNCs.…”

L-cysteine capped ZnS:Mn quantum dots for room-temperature detection of dopamine with high sensitivity and selectivity

“…Its optical sensing is based on the interaction of a fraction of atoms/molecules on a treated surface, which strongly affects the recombination of electrons and holes within the particles, and in turn the emission response . Following this process, many analytes have been successfully detected, such as ions (Hg 2 þ , Co 2 þ , Zn 2 þ and Zr 4 þ ) (Bian et al, 2014;Gong et al, 2014a;Ren et al, 2011;Tan et al, 2012); proteins/enzymes, clenbuterol and glucose in biological fluids (Gong et al, 2014b;Wu et al, 2013;Wu et al, 2010;Zhang et al, 2013); organophosphorus pesticides (Ban et al, 2014); phenols in different media (Liu et al, 2010;Wei et al, 2015;Zhang et al, 2015b); and cathecol, domoic acid, rutin, urea, idarubicin and DNA (Bi et al, 2014;Dan et al, 2013;Ertas et al, 2015;Miao et al, 2014;Wang et al, 2013). Recently, Bian and co-workers, employing N-acetyl-L-cysteine and L-cysteine capped ZnS:Mn QDs as probes, showed the luminescent detection of L-ascorbic acid (AA) with high selectivity and long luminescence lifetime (Bian et al, 2013).…”

A selective determination of copper ions in water samples based on the fluorescence quenching of thiol‐capped CdTe quantum dots

“…When the pH was < 8.5, the fluorescence intensity change decreased as a result of deconstruction of the Cd 2+ –GSH complexes’ annulus due to the protonation of the surface‐binding thiolates . Increasing the pH to > 8.5 resulted in a fluorescence intensity change of the GSH‐capped CdTe QDs, which also decreased due to the Cd 2+ on the surface of the CdTe QDs interacting with the OH − in the solution leading to the formation of Cd(OH) 2 that was coated onto the surface of the GSH‐capped CdTe QDs . Therefore, 0.2 M phosphate buffer at pH 8.5 was chosen for further experiments.…”

“…Quantum dots (QDs) have attracted increasing attention in recent years due to their good optical properties, good photochemical stability, long fluorescence lifetime and good water solubility . Several QDs have been synthesized and used as a fluorescence probe, for example, CdSe , CdTe , CdSe/CdS , ZnS , ZnSe and CdHgSe . Among these, CdTe QDs have been the most widely used because they can be easily synthesized under mild conditions.…”