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 S(2-)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 fluoescence of L-CC was recovered quickly within 10 s in aqueous solution by displacement of Cu2+ after adding S(2- )with an extremely low detection limit for S(2- )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 S(2-)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 S(2-)in water, which shows good potential in on -site water quality monitoring.