title: Functionalized HMS mesoporous silica as solid phase extractant for Pb(II) prior to its determination by flame atomic absorption spectrometry.
abstract: In this work, a mesoporous silica has been chemically modified with 5-mercapto-1-methyl-1-H-tetrazol using the homogeneous route (MTTZ-HMS). This synthetic route involved the reaction of 5-mercapto-1-methyl-1-H-tetrazol with 3-chloropropyltriethoxysilane, prior to immobilization on the support. The resulting material has been characterized and employed as solid phase extractant for Pb(II). The effect of several variables (stirring time, pH, temperature, metal concentration, presence of other metals) has been studied using batch and column techniques. In batch experiments, 15 min stirring time, 55 degrees C and pH 8 were the optimal conditions for Pb(II) adsorption. In column experiments, sorption was quantitative for 1000 mL of 2.41 x 10(-4 )mM of Pb(II) solution and adsorbed ions were eluted out by 5 mL of 1 M HCl (preconcentration factor of 200). Spiked tap water was used for the preconcentration and determination of Pb(II) by flame atomic absorption spectrometry, and a 100% recovery was obtained. The LOD and LOQ values of the proposed method were found to be 3.52 x 10(-3) and 4.20 x 10(-3 )mM, respectively. The RSD for three preconcentration experiments was found to be <or= 2%. The linear working range for measurements was between 2 x 10(-3 )and 0.14 mM (y = 0.0136x + 0.0007, R(2 )= 0.9999).
authors.affiliation: Departamento de Química Inorgánica y Analítica, E.S.C.E.T, Universidad Rey Juan Carlos, C/ Tulipán s/n, Móstoles, Madrid, Spain.
authors.forename: Damián
authors.initials: D
authors.lastname: Pérez-Quintanilla
authors.forename: Alfredo
authors.initials: A
authors.lastname: Sánchez
authors.forename: Isabel
authors.initials: I
authors.lastname: del Hierro
authors.forename: Mariano
authors.initials: M
authors.lastname: Fajardo
authors.forename: Isabel
authors.initials: I
authors.lastname: Sierra
mesh_terms: D007854:Lead / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D008422:Materials Testing; D019216:Metals, Heavy / Q000032:analysis; D015394:Molecular Structure; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*; D052616:Solid Phase Extraction / Q000379:methods*; D013054:Spectrophotometry, Atomic / Q000379:methods*; D017550:Spectroscopy, Fourier Transform Infrared; D013777:Tetrazoles / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D019216:Metals, Heavy; D013777:Tetrazoles; C038625:1-N-methyl-5-thiotetrazole; D007854:Lead; D012822:Silicon Dioxide