An Ionic 1,4-Bis(styryl)benzene-Based Fluorescent Probe for Mercury(II) Detection in Water via Deprotection of the Thioacetal Group

Abstract

Highly sensitive and selective mercury detection in aqueous media is urgently needed because mercury poisoning usually results from exposure to water-soluble forms of mercury by inhalation and/or ingesting. An ionic conjugated oligoelectrolye (M1Q) based on 1,4-bis(styryl)benzene was synthesized as a fluorescent mercury(II) probe. The thioacetal moiety and quaternized ammonium group were incorporated for Hg2+ recognition and water solubility. A neutral Hg2+ probe (M1) was also prepared based on the same molecular backbone, and their sensor characteristics were investigated in a mixture of acetonitrile/water and in water. In the presence of Hg2+, the thioacetal group was converted to aldehyde functionality, and the resulting photoluminescence intensity decreased. In water, M1Q successfully demonstrated highly sensitive detection, showing a binding toward Hg2+ that was ~15 times stronger and a signal on/off ratio twice as high, compared to M1 in acetonitrile/water. The thioacetal deprotection by Hg2+ ions was substantially facilitated in water without an organic cosolvent. The limit of detection was measured to be 7 nM with a detection range of 10–180 nM in 100% aqueous medium.

A Simple and Highly Structured Procaine Hydrochloride as Fluorescent Quenching Chemosensor for Trace Determination of Mercury Species in Water

“…This value was significantly lower than the maximum allowable mercury concentration (10.0 nM) by USEPA in drinking water [17]. The proposed method [30,[37][38][39][40][41]43], electrochemical sensor [42], spectrophotometric [44,48], colorimetry [45,49], chemiluminescence [46], single-crystal X-ray diffraction [47], electrochemiluminescence biosensor [50], X-ray fluorescence (XRF) [51], differential pulse voltammetry [36,52], ICP-OES [21], electrochemical [50] and X-ray photoelectron spectroscopy (XPS) [53], in terms of LOD and LOQ (Table 4).…”

“…Recently, several molecular probe-based sensors using organic chromophores, quantum dots (QDs), small fluorescent organic molecules, proteins, antibodies and conjugated polymers coupled with several spectrometric and electrochemical techniques are reported for mercury(II) determination [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53]. Some of these methods suffere from solubility issues, low stability, lower sensitivity and selectivity, complicated synthesis procedures and environmentally unfriendliness to monitor mercury(II) in biological and environmental samples.…”

A Microfluidic Aptamer-Based Sensor for Detection of Mercury(II) and Lead(II) Ions in Water

“…Finally, to verify the detected The results show that the fluorescence intensity increases linearly with an increasing Hg 2+ and Pb 2+ concentration over the ranges of 10~250 nM (i.e., 2.0~50 ppb) and 10~100 nM (i.e., 2.1~20.7 ppb), respectively. Moreover, the 3.3σ/slope was used to determine the limits of detection (LoD), where σ is the standard deviation of the response [53,54]. The LoD of Hg 2+ and Pb 2+ is equal to 0.70 ppb and 0.53 ppb, respectively.…”