Selective and Sensitive Detection of Cyanide Based on the Displacement Strategy Using a Water-Soluble Fluorescent Probe.

Ming La,Yuanqiang Hao,Guo-Cheng Han,Zhaoyang Wang,Lingbo Qu

doi:10.1155/2016/1462013

Abstract

A water-soluble fluorescent probe (C-GGH) was used for the highly sensitive and selective detection of cyanide (CN−) in aqueous media based on the displacement strategy. Due to the presence of the recognition unit GGH (Gly-Gly-His), the probe C-GGH can coordinate with Cu2+ and consequently display ON-OFF type fluorescence response. Furthermore, the in situ formed nonfluorescent C-GGH-Cu2+ complex can act as an effective OFF-ON type fluorescent probe for sensing CN− anion. Due to the strong binding affinity of CN− to Cu2+, CN− can extract Cu2+ from C-GGH-Cu2+ complex, leading to the release of C-GGH and the recovery of fluorescent emission of the system. The probe C-GGH-Cu2+ allowed detection of CN− in aqueous solution with a LOD (limit of detection) of 0.017 μmol/L which is much lower than the maximum contaminant level (1.9 μmol/L) for CN− in drinking water set by the WHO (World Health Organization). The probe also displayed excellent specificity for CN− towards other anions, including F−, Cl−, Br−, I−, SCN−, PO4 3−, N3 −, NO3 −, AcO−, SO4 2−, and CO3 2−.

Highlights

The development of effective methods for the recognition and sensing of anions has recently received considerable attention due to the importance of these species in biological and industrial processes [1,2,3,4,5,6]
We reported a fluorescent probe CGGH by incorporation of a natural tripeptide GGH (Gly-GlyHis) moiety to a coumarin fluorophore
A water-soluble fluorescent probe C-GGH was successfully used for recognition of Cu2+ and CN− based on the displacement strategy

Summary

Introduction

The development of effective methods for the recognition and sensing of anions has recently received considerable attention due to the importance of these species in biological and industrial processes [1,2,3,4,5,6]. Journal of Analytical Methods in Chemistry sensing: (i) coordination to electron-deficient center [15], (ii) nucleophilic addition to the electron-deficient π-system [22, 23], (iii) hydrogen-bonding interaction [24, 25], and (iv) metal-CN− affinity (displacement approach) [26,27,28,29] Among these four approaches, the displacement strategy, where CN− extracts Cu2+ from the metal receptor complex to form stable Cu(CN)x, resulting in a detectable optical signal, has attracted special attention. Taking advantage of the natural tripeptide GGH, the probe exhibits excellent biocompatibility and water solubility [30] We exploited this probe for the detection of CN− based on a displacement sensing strategy. The ensemble CGGH-Cu2+ allowed detection of CN− in aqueous solution with high sensitivity and excellent selectivity

Experimental

Results and Discussion

Conclusions