Spectrofluorimetric determination of mercury(II) using a new bidentate polyethylene glycol ligand (BPEG)

Abstract

A new fluorogenic water-soluble bidentate polyethylene glycol (BPEG) ligand has been applied to the spectrofluorimetric determination of trace mercury(II). BPEG forms a water-soluble complex with mercury(II). Excitation and fluorescence wavelengths of BPEG in the presence of mercury(II) were 313 and 445 nm, respectively. Fluorescence intensity of the complex increased proportionally to the concentration of mercury(II) at pH 5 (acetic acid-acetate sodium buffer) in the presence of Triton X-100 surfactant. The highest sensitivity of mercury(II) determination was achieved at BPEG concentration of 1.0 x 10(-1) mol L-1. Interferences from Al3+ and Fe3+ were completely eliminated by masking the ions with fluoride ion. Linear range in the calibration plot for mercury(II) was 5-180 mu g L-1, detection limit equalled 2 mu g L-1 (RSD = 1.7%, n = 10). The method was successfully applied to the determination of mercury(II) in drain water of dentistry units, synthetic mixtures of various compositions, as well as well-, river- and tap water samples.