Highly Selective Potentiometric Membrane Sensor for Hg(II) Based on Bis(Benzoyl Acetone) Diethylene Triamine

摘要

A new ion selective PVC membrane sensor is described based on bis(benzoyl acetone) diethylene triamine as a potentiometric sensor for ${rm Hg}^{2+}$ ions. The membrane having bis(benzoyl acetone) diethylene triamine as an electroactive material, sodium tetraphenyl phthalate (NaTPB), and dibutyl phthalate (DBP) as an anion excluder in PVC matrix in the percentage ratio of 4.21:2.11:60.25:33.43 (Ionophore:NaTPB:DBP:PVC) (w/w) exhibits a linear response to $hbox{Hg}^{2+}$ ions in a concentration range of $1.0times 10^{-6}$ to $1.0times 10^{-1} hbox{M}$ with a limit of detection of $3.7times 10^{-7} hbox{M}$ and with a slope of 29.8 $pm$ 1.0 mV/decade over the pH range of 2.0–11.5. Selectivity coefficients for Hg(II) relative to a numbers of potential interfering ions were investigated. The sensor is highly selective for $hbox{Hg}^{2+}$ ions over a large number of mono-, bi-, and trivalent cations. Normal interferents like $hbox{Ag}^{+}$ and $hbox{Cd}^{2+}$ do not interfere in the working of the sensor. The sensor has been found to be chemically inert to other ions and showing a fast response time of 1 s and was used over a period of three months with a good reproducibility. The sensor was successfully applied to determine mercury(II) in water samples with satisfactory results.