title: An optical chemical sensor for mercury ion based on 2-mercaptopyrimidine in PVC membrane.
abstract: An optical chemical sensor based on 2-mercaptopyrimidine (2-MP) in plasticized poly(vinyl chloride) (PVC) membrane incorporating (N,N-diethyl-5-(octadecanoylimino)-5H benzo[a]phenoxazine-9-amine (ETH 5294) and sodium tetraphenyl borate (NaTPB) for batch and flow-through determination of mercury ion is described. The response of the sensor is based on selective complexation of Hg(2+) with 2-MP in the membrane phase, resulting in an ion exchange process between H(+) in the membrane and Hg(2+) in the sample solution. The influences of several experimental parameters, such as membrane composition, pH, and type and concentration of the regenerating reagent, were investigated. The sensor has a response range of 2.0 x 10(-9) to 2.0 x 10(-5) mol L(-1) Hg(2+) with a detection limit of 4.0 x 10(-10) mol L(-1) and a response time of < or = 45 s at optimum pH of 6.5 with high measurement repeatability and sensor-to-sensor reproducibility. It shows high selectivity for Hg(2+) over several transition metal ions, including Ag(+), Cd(2+), Co(2+), Cr(3+), Cu(2+), Fe(3+), Mn(2+), Ni(2+), and common alkali and alkaline earth ions such as Na(+), K(+), Mg(2+), Ca(2+), and Pb(2+). The sensor membrane can be easily regenerated with dilute acid solutions. The sensor has been used for the determination of mercury ion concentration in water samples.
authors.affiliation: Chemistry Department, University of Isfahan, Isfahan, 81746-73441, Iran.
authors.forename: Bahareh
authors.initials: B
authors.lastname: Khezri
authors.forename: Mohammad K
authors.initials: MK
authors.lastname: Amini
authors.forename: Ali R
authors.initials: AR
authors.lastname: Firooz
mesh_terms: D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000032:analysis; D008567:Membranes, Artificial; D008628:Mercury / Q000032:analysis*; D015394:Molecular Structure; D055095:Optics and Photonics; D011143:Polyvinyl Chloride / Q000737:chemistry*; D011743:Pyrimidines / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013499:Surface Properties; D013997:Time Factors
chemical_list: D007477:Ions; D008567:Membranes, Artificial; D011743:Pyrimidines; C064001:pyrimidine-2-thiol; D011143:Polyvinyl Chloride; D008628:Mercury