Highly sensitive and selective fluorescent assay for quantitative detection of divalent copper ion in environmental water samples

• Published in: Analytical methods 2011-09, Vol.3 (9), p.2102-2107
• Main Authors: Cao, Haiyan, Shi, Wenbing, Xie, Jianxin, Huang, Yuming
• Format: Article
• Language: English
• Subjects: Catalysis; Catalysts; Copper; Fluorescence; Mathematical analysis; Oxidation; Spectra; Standard deviation
• ISSN: 1759-9660; 1759-9679
• DOI: 10.1039/c1ay05298e

It was found that Cu2+ has a great catalytic effect on p-cresol oxidation by hydrogen peroxide under alkaline conditions, leading to an intense fluorescence signal due to the fast formation of 2,2[prime or minute]-dihydroxy-5,5[prime or minute]-dimethylbiphenyl, an oxidation product of p-cresol. Investigation of the fluorescence spectra of the p-cresol-hydrogen peroxide system demonstrated the catalytic behavior of Cu2+. On this basis, a very simple, sensitive, and selective fluorescent method was established for the determination of trace copper in this study. Under the optimal conditions, the proposed system could respond down to 1.0 [times] 10-8 mol L-1 of Cu2+ with a linear calibration range of 3.0 [times] 10-7 mol L-1 to 5.0 [times] 10-5 mol L-1. The relative standard deviation (RSD) was 2.1% for 7.0 [times] 10-6 mol L-1 Cu2+ (n = 15). The proposed method was successfully applied in the determination of trace Cu2+ in lake, river and swimming pool water samples with satisfactory results. The results obtained by the proposed method are in good agreement with those obtained by a conventional atomic absorption spectroscopy method.