The fluctuation of the halide ion concentration in human serum is of a high clinical implication. The measurement of Cl- in human serum samples is important because Cl- is a major constituent of human serum and certain Cl- levels are indicators of many acute diseases. Real-time monitoring of Br- levels in human serum samples from patients ingesting Br- salt-based antiepileptic drugs is important to regulate potential adverse drug effects. In this study, we developed a fluorescent probe for the discriminative sensing of Cl- and Br- using a naphthalimide-benzimidazole conjugate-based Ag+ complex (L1-Ag+ complex) by exploiting the strong interaction between Ag+ and halide ions with selectivity control by pH variation. The probe exhibited a dual function of detecting Cl- and Br- at pH levels of 4.5 and 8.0, respectively. Under this two pH conditions, the probe showed a high sensitivity (limit of detection (LOD) = 43 and 5 μM for Cl- and Br-, respectively) and selectivity toward Cl- and Br-. Importantly, the probe could be applied in the quantification of Cl- and Br- levels in human serum samples under two conditions: Cl- in normal human serum and Br- in the serum-mimicking that of epileptic patients during medication.
Keywords: Dual-functional; Fluorescent chemosensor; Halide ion; Ligand exchange.
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