Detection of S^2- in Water by a Glucose Enhanced Water-Soluble Fluorescent Bioprobe

That sulfide anions (S^2-) in aquatic environments are produced by microorganisms through degrading sulfur-containing proteins and other organics are harmful to human health. Thus, it is of significance to develop a convenient method for the detection of S^2- in water. Small molecular fluorescent probes are very popular for their advantages of visualization, real-time, high sensitivity, and convenience. However, low solubility in water limits the application of existing S^2- probes. In this work, we found that our previously developed water-soluble glycosylated fluorescent bioprobe Cu[GluC] can achieve detection of S^2- in water. Cu[GluC] can restore fluorescence within 20 s when it encounters S^2- and shows good sensitivity towards S^2- with a detection limit of 49.6 nM. Besides, Cu[GluC] derived fluorescent test strips were obtained by immersion and realized conveniently visual S^2- detection in water by coupling with a UV lamp and a smartphone app. This work provides a fluorescent bioprobe with good water solubility as well as its derived fluorescent test strip for sensitive and simple detection of S^2- in water, which shows good prospects in on-site water quality monitoring.