A PVC Plasticized Sensor for Ni(II) Ion Based on a Simple Ethylenediamine Derivative

Abstract

There has been a profound development in potentiometric sensors over the past 3 -4 decades, mainly thanks to their use in many fields like agriculture, industry, environment and pharmacy. The need for developing a sensor that is fast, accurate, reproducible and above all, selective to the ion of interest is the main reason for the quantum leap. The major challenge of research in this field has been in designing and subsequent syntheses of the different types of ionophores and this has been the thrust area of research. 1,2 Nickel monitoring has become quite essential mainly due to the material's toxic nature. It is a potent carcinogen and it causes acute pneumonitics, dermatitis, asthma, and nasal and lung cancer. 3,4 Nickel is present at low concentrations in hydrogenated oils, milk, and milk products and also in electroplating effluents. The conventional methods, such as the gravimetric method using dimethylglyoxime 5 or the spectrophotometric method, 6 are not only time consuming but also have some practical inconveniences. Though a number of ion selective electrodes are reported in the literature, 7-15 most of them are associated with one or other drawbacks like poor selectivity, narrow concentration range, non-Nernstian response, relatively long response time or poor reproducibility.In continuation to our work on metal analyses at trace levels, 16,17 this paper presents the fabrication of a PVC matrix membrane sensor incorporating a Schiff base as ionophore and its use in the determination of Ni(II). The proposed sensor could be effectively applied for direct determination of nickel content in real samples. Experimental ReagentsAll the reagents used were of analytical reagent grade. Dioctyl phthalate (DOP), dioctyl sebacate (DOS), dioctyl adipate (DOA), dimethyl sebacate (DMS), dibutyl phthalate (DBP) and sodium tetraphenylborate (NaTPB) were obtained from Lancaster (UK) and were used without any further purification. The metal salts, high relative molecular weight PVC, tetrakis[3,4-bis(trifluoromethyl)phenyl]borate and dibutyl sebacate (DBS) were purchased from Merck and used without any further purification. Tetrahydrofuran (THF) and oleic acid was purchased from S. D. Fine Chem, India and was distilled before use.The ionophore, N 1 ,N 2 -bis((naphthalen-1-yl)-methylene)ethane-1,2-diamine (NED), was synthesized and purified as described elsewhere (Fig. 1). 18 All the metal salt solutions were prepared in doubly distilled water and solutions of different concentrations were made by serial dilution of the 0.1 M stock solutions. Electrode preparationA mixture of PVC, plasticizer (DOP) and the anion excluder (NaTPB) in the ratio 31:65:2 (w/w%) was dissolved in 5 -7 mL of THF. To this mixture, the ionophore (2%) was added and the solution was mixed well. It was then poured into a petri dish A new PVC membrane ion selective electrode which is highly selective towards Ni(II) ions was constructed using a Schiff base containing a binaphthyl moiety as the ionophore. The sensor exhibited a good Nernstian response for...

An overview of sensors and sensing materials for heavy metals in aqueous environments

“…[122] The incorporation of plasticizers with lower viscosity results in higher diffusivity. [121] For sensing materials, the addition of plasticizers can increase the rate of diffusion, which can improve the sensitivity [123] and reduce the response time of a sensor, [3] especially as the amount of plasticizer incorporated into the polymer is increased. [122] Pejcic et al [124] found that increasing the amount of plasticizer in a PMMA sensing material on a quart crystal microbalance (QCM) resulted in a higher sensitivity towards naphthalene.…”

“…[ 122 ] The incorporation of plasticizers with lower viscosity results in higher diffusivity. [ 121 ] For sensing materials, the addition of plasticizers can increase the rate of diffusion, which can improve the sensitivity [ 123 ] and reduce the response time of a sensor, [ 3 ] especially as the amount of plasticizer incorporated into the polymer is increased. [ 122 ]…”

Ion Recognition: Application of Symmetric and Asymmetric Schiff Bases and Their Complexes for the Fabrication of Cationic and Anionic Membrane Sensors to Determine Ions in Real Samples

“…3 10 -6 Ag + , Co 2+ , Hg 2+ [33] Ni 2+ thiophene-derivative Schiff base 29.5± 1.0 1.0 10 -1 -5.0 10 -6 1.8 10 -6 [34] Ni 2+ N 1 ,N 2 -bis((naphthalen-1-ymethylene)ethane-1,2-diamine 29.9 1.0 10 -1 -5.0 10 -6 1. 3 1.0 10 -5 -1.0 10 -1 3.6 10 -6 , 3.1 10 -6 and 6.…”

“…The first one consisted of a thiophene-derivative Schiff base membrane and was utilized for wastewater samples from electroplating industries and Indian chocolates. On the contrary, the other one had a Schiff base containing a binaphthyl moiety, for the direct determination of nickel content in effluent samples, chocolates and hydrogenated vegetable oils [34,35].…”

Acyclic Arylamine-Based Ionophores as Potentiometric Sensors for Zn2+ and Ni2+ Ions

“…A number of ions selective membranes (ISMs) have been reported with various compounds for the detection of both zinc and nickel. This includes [Bzo2Me2Ph2 (16)hexaeneN4] [36], PME-6,7:14,15-Bzo2-10,11-(4-methylbenzene)- [15]-6,8,12,14-tetraene-9,12-N2-1,5-O2 [37], Dibenzo-24-crown-8 [26], 3-[(2-Furylmethylene)amino]-2-thioxo-1,3-thiazolidin-4-one [38], N,N-Bis(acetylacetone)ethylene diamine [25] for zinc ions and porphyrins, crown ethers, cyclams, amines, and Schiff bases-based molecules for nickel ions [33,34,[39][40][41][42][43].…”