Detection Of Sulfide Anion Research Articles

Lactosylation leads to a water-soluble fluorescent probe for detection of S2− in water

Detection of sulfide anion (S2−), which is a common environmental pollutant in water and a threat to human health through drinking or food, holds great significance. However, most of existing S2− probes are insensitive in aqueous solution due to poor water-solubility. Here, a water-soluble small molecular fluorescent probe L-CC was first developed via introducing lactose to coumarin derivative (L-C) and then coordinating with copper ions (Cu2+). Water solubility endowed by lactose moiety makes L-CC ultrasensitive toward S2− in water. The fluorescence of L-CC was recovered quickly within 10 s in aqueous solution by displacement of Cu2+ after adding S2− with an extremely low detection limit for S2− measured to be 5.20 nM, which make L-CC suitable for testing S2− spiked in some real water samples. What’s more, fluorescent test strips produced by filter papers embedded with L-CC were capable of visual and quantitative analysis of S2− in water with obvious fluorescent color changes. Thus, this work provides a fluorescent probe with good water solubility endowed by lactosylation as well as its derived fluorescent test strip for simple and sensitive detection of S2− in water, which shows good potential in on-site water quality monitoring.

A new near-infrared fluorescent chemodosimeter for discrimination of sulfide from disulfide

A new near-infrared fluorescent “turn-on” chemodosimeter (probe 1) based on dicyanomethylene-4H-chromene fluorophore for sulfide was developed. Probe 1 showed good fluorescence selectivity to sulfide over other anions and thiol-containing compounds. The discrimination of sulfide from disulfide could be achieved by comparison of the spectral difference of probe 1 after interaction with them. The absorption of probe 1 at 437 nm decreased, accompanied by red-shifting to 470 nm as a shoulder, and a strong peak at 610 nm appeared in the presence of sulfide. The absorption of 1 was slightly red-shifted to 452 nm with increased absorbance in the presence of disulfide. Probe 1 showed more than 1000-fold fluorescence enhancement at 712 nm with a Stokes shift of 102 nm in the presence of sulfide. The probe exhibited a good sensitivity in detection of sulfide with a wide pH span (4.0–11.0). The absorption change and fluorescence enhancement could be attributed to thiolysis of the dinitrophenyl ether group in probe 1 by the sulfide. The proposed mechanism was proved by 1H NMR spectra and EI-MS explorations. The probe was successfully applied for the detection of sulfide anions in real water samples.