Potentiometric Detection of Mercury(II) Ions Using a Carbon Paste Electrode Modified with Substituted Thiourea-Functionalized Highly Ordered Nanoporous Silica

A potentiometric sensor is reported for the mercury(II) detection, which uses substituted thiourea-functionalized nanoporous silica (FTU-LUS-1) as the sensitive material. Substituted thiourea (FTU) and FTU-LUS-1 were first prepared and then characterized by 1H NMR, 19F NMR, 13C NMR, FTIR, XRD, TG and CNS elemental analysis. The electrodes with FTU-LUS-1 proportion of 10.0 wt% demonstrated very stable potentials. The prepared electrodes exhibit a Nernstian slope of 28.4 +/- 1.0 mV decade(-1) for mercury(II) ion over a wide concentration range of 1.0 x 10(-7) to 1.0 x 10(-1) mol dm(-3). The electrode exhibited a detection limit of 7.0 x 10(-8) mol dm(-3). Moreover, the selectivity coefficient, response time, performance, sensitivity and stability of the modified electrode were investigated. The electrode presented a response time of about 35 s, a high performance and sensitivity in a wide range of cation activities as well as good long term stability (more than 9 months). The method was satisfactory and could also be used to monitor the mercury(II) ion concentration in waste water and fish samples.

[1]  H. Ju,et al.  Low Potential Detection of NADH at Titanium-Containing MCM-41 Modified Glassy Carbon Electrode , 2007 .

[2]  M. Shamsipur,et al.  Mixed Aza‐Thioether Crowns Containing a 1,10‐Phenanthroline Sub‐Unit as Neutral Ionophores for Silver Ion , 2002 .

[3]  S. Tolbert,et al.  Host−Guest Chemistry Using an Oriented Mesoporous Host: Alignment and Isolation of a Semiconducting Polymer in the Nanopores of an Ordered Silica Matrix , 1999 .

[4]  M. Ganjali,et al.  Novel Method for the Fast Preconcentration and Monitoring of a ppt Level of Lead and Copper with a Modified Hexagonal Mesoporous Silica Compound and Inductively Coupled Plasma Atomic Emission Spectrometry , 2004, Analytical sciences : the international journal of the Japan Society for Analytical Chemistry.

[5]  W. Maher,et al.  Low-volume microwave digestion of marine biological tissues for the measurement of trace elements. , 1994, The Analyst.

[6]  María Vallet-Regí,et al.  Functionalization of mesoporous materials with long alkyl chains as a strategy for controlling drug delivery pattern , 2006 .

[7]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[8]  Mohammad Reza Ganjali,et al.  Carbon Paste Electrode Modified with Functionalized Nanoporous Silica Gel as a New Sensor for Determination of Silver Ion , 2007, Electroanalysis.

[9]  M. Shamsipur,et al.  Nickel ion-selective coated graphite PVC-membrane electrode based on benzylbis(thiosemicarbazone) , 2002 .

[10]  Andrew G. Glen,et al.  APPL , 2001 .

[11]  Pico Level Monitoring of Silver with Modified Hexagonal Mesoporous Compound (MCM-41) and Inductively Coupled Plasma Atomic Emission Spectrometry , 2006 .

[12]  S. Apte,et al.  Determination of Methylmercury in Natural Water Samples by Steam Distillation and Gas Chromatography−Atomic Fluorescence Spectrometry , 1998 .

[13]  A. Walcarius,et al.  Rate of Access to the Binding Sites in Organically Modified Silicates. 3. Effect of Structure and Density of Functional Groups in Mesoporous Solids Obtained by the Co-Condensation Route , 2003 .

[14]  J. B. Higgins,et al.  A new family of mesoporous molecular sieves prepared with liquid crystal templates , 1992 .

[15]  H. Sharghi,et al.  A 9,10-Anthraquinone Derivative Having Two Propenyl Arms as a Neutral Ionophore for Highly Selective and Sensitive Membrane Sensors for Copper(II) Ion , 2002, Analytical sciences : the international journal of the Japan Society for Analytical Chemistry.

[16]  J. Tyson,et al.  Flow injection determination of mercury with preconcentration by amalgamation on a gold–platinum gauze by inductively coupled plasma mass spectrometry , 1996 .

[17]  Sang Mi Park,et al.  Sensitized spectrophotometric determination of trace Hg(II) in benzalkonium chloride media , 2002 .

[18]  J. Yi,et al.  Synthesis of functionalized porous silicas via templating method as heavy metal ion adsorbents: the introduction of surface hydrophilicity onto the surface of adsorbents , 2001 .

[19]  Bradley F. Chmelka,et al.  Nonionic Triblock and Star Diblock Copolymer and Oligomeric Surfactant Syntheses of Highly Ordered, Hydrothermally Stable, Mesoporous Silica Structures , 1998 .

[20]  D. Mandler,et al.  Electrochemical determination of ultralow levels (<10−12 M) of mercury by anodic stripping voltammetry using a chemically modified electrode , 1994 .

[21]  M. Ganjali,et al.  Use of organofunctionalized nanoporous silica gel to improve the lifetime of carbon paste electrode for determination of copper(II) ions. , 2007, Analytica chimica acta.

[22]  Jin-Song Hu,et al.  Electrochemical sensor for detecting ultratrace nitroaromatic compounds using mesoporous SiO2-modified electrode. , 2006, Analytical chemistry.

[23]  A. Walcarius,et al.  Rate of Access to the Binding Sites in Organically Modified Silicates. 2. Ordered Mesoporous Silicas Grafted with Amine or Thiol Groups , 2003 .

[24]  M. Ganjali,et al.  Stripping Voltammetry of Cerium(IIl) with a Chemically Modified Carbon Paste Electrode Containing Functionalized Nanoporous Silica Gel , 2008 .