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

Abstract

A new ion selective PVC membrane sensor is described based on bis(benzoyl acetone) diethylene triamine as a potentiometric sensor for Hg <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> 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 4.21:2.11:60.25:33.43 (Ionophore:NaTPB:DBP:PVC) (w/w) of exhibits a linear response to Hg <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> of 1.0 times 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-6</sup> to 1.0 times 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> M with a limit of detection of 3.7 times 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-7</sup> M and with a slope of 29.8 plusmn 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 Hg <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> ions over a large number of mono-, bi-, and trivalent cations. Normal interferents like Ag <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> and Cd <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> 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.