A Sensor Array for the Ultrasensitive Discrimination of Heavy Metal Pollutants in Seawater

摘要

Metal cations are potent environmental pollutants that negatively impacthuman health and the environment. Despite advancements in sensor design,the simultaneous detection and discrimination of multiple heavy metals atsub-nanomolar concentrations in complex analytical matrices remain a majortechnological challenge. Here, the design, synthesis, and analytical performanceof three highly emissive conjugated polyelectrolytes (CPEs) functionalizedwith strong iminodiacetate and iminodipropionate metal chelates thatoperate in challenging environmental samples such as seawater are demonstrated.When coupled with array-based sensing methods, these polymericsensors discriminate among nine divalent metal cations (Cu~Ⅱ, CoⅡ, Ni~Ⅱ, Mn~Ⅱ,Fe~Ⅱ, Zn~Ⅱ, Cd~Ⅱ, Hg~Ⅱ, and Pb~Ⅱ). The unusually high and robust luminescence ofthese CPEs enables unprecedented sensitivity at picomolar concentrations inwater. Unlike previous array-based sensors for heavy metals using CPEs, theincorporation of distinct π-spacer units within the polymer backbone affordsmore pronounced differences in each polymer’s spectroscopic behavior uponinteraction with each metal, ultimately producing better analytical informationand improved differentiation. To demonstrate the environmental andbiological utility, a simple two-component sensing array is showcased thatcan differentiate nine metal cation species down to 500 × 10~（?12） m in aqueousmedia and to 100 × 10~（?9） m in seawater samples collected from the Gulf ofMexico.