Ultrasensitive detection of lead(II) using a turn-on probe based on the use of an aptamer and a water-soluble fluorescent perylene probe

The authors describe an ultra-sensitive approach for the determination of lead(II) by using a lead-specific aptamer and a fluorophore derived from perylenetetracarboxylic acid diimide (PTCDI). The fluorescence of PTCDI, with excitation/emission peaks at 494/543 nm, is quenched by the aptamer but restored if the aptamer binds lead(II). A detection scheme has been worked out that has a 0.1 ng center dot mL(-1)limit of detection and a dynamic range that extends from 0.1 ng center dot mL(-1) to 10 mu g center dot mL(-1). The assay also demonstrates high selectivity for lead ions over nine other ions due to the aptamer's high specificity. The method shows a average recovery of 77.2-93.4% with an RSD of less than 3% in water samples.