A Novel Multifunctional Near-Infrared Absorbing Dye for Hg2+ Recognition

A novel near-infrared absorbing colorimetric sensor with multifunctional groups, bis-dibenzo-18-crown-6 squaraine (BCSQ), has been identified and applied for accurate Hg2+ analysis based on the decrement of its UV absorbance (A) in the aqueous medium. The proposed method was successfully applied to analyse synthetic Hg2+ samples and natural Hg2+ samples. The results show that the linear range of Hg2+ detection in aqueous medium is 7.5~150×108 mol·L1 with a correlation coefficient (R) of 0.9983 and a limit of detection (3σ, n=20) of 5.6 ×109 mol·L1. The relative standard deviation (R.S.D.) for Hg2+ detection was lower than 2.4% (n=5). The proposed method possesses the advantages of simplicity, rapidity, high selectivity and sensitivity.