title: A new Schiff's base ligand immobilized agarose membrane optical sensor for selective monitoring of mercury ion.
abstract: A highly selective optical sensor was developed for the Hg(2+) determination by chemical immobilization of 2-[(2-sulfanylphenyl)ethanimidoyl]phenol (L), on an agarose membrane. Spectrophotometric studies of complex formation between the Schiff's base ligand L and Hg(2+), Sr(2+), Mn(2+), Cu(2+), Al(3+), Cd(2+), Zn(2+), Co(2+) and Ag(+) metal ions in methanol solution indicated a substantially larger stability constant for the mercury ion complex. Consequently, the Schiff's base L was used as an appropriate ionophore for the preparation of a selective Hg(2+) optical sensor, by its immobilization on a transparent agarose film. A distinct color change, from yellow to green-blue, was observed by contacting the sensing membrane with Hg(2+) ions at pH 4.5. The effects of pH, ionophore concentration, ionic strength and reaction time on the immobilization of L were studied. A linear relationship was observed between the membrane absorbance at 650 nm and Hg(2+) concentrations in a range from 1×10(-2) to 1×10(-5) mol L(-1) with a detection limit (3σ) of 1×10(-6) mol L(-1). No significant interference from 100 times concentrations of a number of potentially interfering ions was detected for the mercury ion determination. The optical sensor was successfully applied to the determination of mercury in amalgam alloy and spiked water samples.
authors.affiliation: Department of Chemistry, Lorestan University, Falakolaflak St., Khorramabad, Lorestan 6813717133, Iran. Alizadehk@yahoo.com
authors.forename: Kamal
authors.initials: K
authors.lastname: Alizadeh
authors.forename: Razieh
authors.initials: R
authors.lastname: Parooi
authors.forename: Payman
authors.initials: P
authors.lastname: Hashemi
authors.forename: Behrooz
authors.initials: B
authors.lastname: Rezaei
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Ganjali
mesh_terms: D002138:Calibration; D003723:Dental Amalgam / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D007476:Ionophores; D008024:Ligands; D008567:Membranes, Artificial; D008628:Mercury / Q000737:chemistry*; D008958:Models, Molecular; D015203:Reproducibility of Results; D012545:Schiff Bases / Q000737:chemistry*; D012685:Sepharose / Q000737:chemistry*; D012996:Solutions; D013056:Spectrophotometry, Ultraviolet; D013438:Sulfhydryl Compounds / Q000737:chemistry; D014867:Water / Q000032:analysis
chemical_list: D007202:Indicators and Reagents; D007476:Ionophores; D008024:Ligands; D008567:Membranes, Artificial; D012545:Schiff Bases; D012996:Solutions; D013438:Sulfhydryl Compounds; D014867:Water; D003723:Dental Amalgam; D012685:Sepharose; D008628:Mercury