Chemically Modified Multiwalled Carbon Nanotubes as Efficient Material for Construction of New Zinc (II) Ion Selective Carbon Paste Electrode

Multiwalled carbon nanotubes surface chemically (MWCNT) was modified by a couple reactions between trimethoxysilylpropylamine (TMSPA) and 2-hydroxybenzaldehyde (2-HBA) and characterized by FT-IR technique. This new material (MWCNT-SPIMP) in carbon paste electrode matrices selectively the Zn2+ ion. The influences of variables including sodium tetraphenylborate (NaTPB), amount of MWCNT-TMSPA, Nujol and graphite powder on electrode response has been investigated and their value was set as graphite powder: NaTPB: Nujol: carrier in the mass (mg) ratio of 150/4.0/30.0/100. At the optimum value set as above the proposed Zn2+ selective electrode response is linear over the wide range concentration of 1.0 x 10(-7) to 5.0 x 10(-2) mol L-1 with slope of 29.70 mV per decade(-1) of Zn2+ ion concentration with detection limit of 7.0 X 10(-8) mol L-1. The electrode response is independent of pH in the range of 3.5-6.5 with a short the response time of about 5 s. The potentiometric selectivity coefficients and selectivity sequence of proposed Zn2+ ion selective electrode has been evaluated using fixed interference method (FIM), separation solution method (SSM) and matched potential method (MPM). The proposed electrode successfully has been applied for potentiometric determination of Zn2+ ion content in various real samples and as indicator electrode for potentiometric titration of EDTA.