Application of a triacetylcellulose membrane with immobilizated of 5-(2′,4′-dimethylphenylazo)-6-hydroxypyrimidine-2,4-dione for mercury determination in real samples

The fabrication of an optical sensor membrane is described for the determination of Hg2+ ions based on the immobilization of 5-(2',4'-dimethyl-phenylazo)-6-hydroxypyrimidine-2,4-dione (DMPAHPD) on a triacetyl-cellulose membrane. The membrane responds to mercury ions by changing color reversibly from orange to deep red in thiel buffer solution at pH 8.5. Under optimum conditions, the proposed membrane displayed a linear range of 1.0-80 ng/mL with a limit of detection of 0.3 ng/mL at a wavelength of 594 nm. The response time of the optode was about 3.0-5.0 min, depending on the concentration of Hg2+ ions. The coefficient of variation (CV) of the sensor response for 40 ng/mL of Hg2+ was 1.2% and the CV between seven membranes was 1.45%. The optode is fully reversible and the selectivity of optode to Hg2+ ions is relatively good with Ni2+ ions as interferences. The proposed optode was applied successfully for the determination of Hg2+ ions in real samples. (C) 2015 Elsevier B.V. All rights reserved.