Title of Invention	A DEVICE USEFUL FOR SENSING COPPER (II) ION IN FLUIDS
Abstract	A solid state copper (II) ion sensor which comprises coating a metallic electrode with an electroactive conducting polymer such as herein described, in neutral/undoped state and if desired, providing an insulating protective outer covering in such a manner so as to allow fluid contact with the resultant electrode

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The present invention particularly relates to a device useful for sensing Copper (II) ion in fluids. There has been considerable interest in the use of ion selective electrodes (ISEs) for various purposes and particularly in the analytical, biological and clinical areas. Accordingly, extensive studies have been made on the development of ion-selective-electrodes (ISEs) based on unblocked (with conventional double barrel configuration) and blocked (coated wire electrode, CWE) interfaces. Many conventional ion selective electrodes or ion sensors (without using conducting polymers) are known in art which are having major drawbacks: i) noise at the steady-state potential and ii) the sharp variation in a radon order of the standard electrode potential in random manner, iii) Bi-layer configuration of the sensor electrode is required In the view of above disadvantages there are few major requirements which restrict the development of several earlier reported researches on this topic. These are; 1) Variable base line steady state potentiometer response together with standard reference electrode which subsequently requires standardization of the ISEs before each set of measurements; 2) Relatively least non-polarizability of the sensors leading to the sensitivity of the potenstiometiric signal on external environmental stimulus; 3) Poor contact between ion-element and solid-state metal to be used in sensor design that restrict the long term reproducibility of the sensor. These drawbacks were minimized by using electro active conducting polymers and few sensor electrode which uses conducting polymers andean ion-sening material preferably within plasticized PVC matrix membrane are known in art [Ref. P.C. Pandey and R. Prakash, Sensors and Actuators, 46 (1998) 61-65) and T. Momma, S. Komaba, M. Yamamoto, T. Osaka and S. Yamauchi, Sensors and Actuators, B 24-25 (1995) 724-728 ] but none of sensor electrode without ion-carriers/ ion-sensing material particularly for sensing copper ion is known so for. Still few disadvantages are associated with the conducting polymers/PVC based bilayer sensing electrodes e.g. sluggish response and leaching of the dopants in the conducting polymers and hence stability of the electrodes. These drawbacks were minimised by using a sengle ion senssing layer of nertral/undoped conducting polymer. The;Cu++ ion sensor is developed based on the single layer of undoped conducting polymer, which is having many advantages over conventional double layer ion-sensing electrodes. Need of copper ion sensor is very important for the detection of the Cu ions in the various industrial discharges and also m ground water and rivers, where the contamination may be by natural sources. So for no any ion-selective electrode was reported based on the single layer conducting polymer. Hence this Cu (II) ion sensor based on the conducting polymer e.g. Polycarbazole and polyindole is novel and have many advantages. The main object of the present invention is to provide a solid state copper (II) ion sensor for the use of industries and river/ ground water testing. Another objective of the present invention is to provide the use of a conducting polymer such as polycarbazole and polyindole as a new type of sensing material for Cu(ll) ions. Yet another objective of the present invention is to provide a simplified single layer based ion-selective electrode. Still another object is to provide a device useful for sensing Copper ion in fluid. The present invention for the first time reports a conducting polymer based Cu(ll) ion sensor. In the present invention, a neutral conducting polymer coated electrode (Single layer) alone is used for sensing the Cu (II) ions in the fluid. Further a very simple configuration of the electrode is constructed by using metal electrode coated with conducting polymer. So there is no need of nay complicated design of the electrode, and just a metal wire/plate/disk electrode can work The present invention can also be used in a miniaturized form. Sensor electrode shows quite fast response. Based on the above approach, we tried other conducting polymers e.g. Polyaniline, Polyyrrole and Polythiophenes, though these polymers show responses for Cu(II) ions but these did not fulfill the critical requirements for the sensors e.g. sensitivity, potential response, reversibility and stability. The novelty of the present invention lies in the use of the conducting polymer such as polycarboazole and polyindole as a Cu (II) ion selective material. Accordingly, the present invention provides, a device useful for sensing Copper (II) ion in fluids characterized by a novel solid state copper (II) ion sensor, and a reference electrode placed in a container for holding the fluid in which copper ion is to be detected, the potential outputs of the said electrode pair being connected to means such as herein described, for measuring potential difference which is the direct measurement of the copper (II) ion in fluids, the said novel solid state copper (II) ion sensor essentially consists of coating a metallic electrode such as herein described, with a single layer electroactive conducting polymer selected from polycarbazole, polyindole or its copolymers and derivatives, in neutral/undoped state and if desired, providing an insulating protective outer covering so as to allow fluid contact with the resultant electrode. Accordingly, the present invention provides a solid state copper (II) ion sensor which comprises coating a metallic electrode with an electroactive conducting polymer such as herein described, in neutral/undoped state and if desired, providing an insulating protective outer covering in such a manner so as to allow fluid contact with the resultant electrode . The invention further provides a device useful for sensing Copper (II) ion in fluids which comprises a solid state copper (II) ion sensor and a reference electrode placed in a suitable container for holding the fluid in which copper ion is to be detected, the potential out puts of the said electrode pair being connected to means for measuring potential difference which is the direct measurement of the copper (II) ion in fluids. In an embodiment of the invention, the elector active conducting polymers used may be selected from polycarbazole, polyindole or its copolymers and derivatives. In another embodiment of the invention, the metal electrode used is such as Gold, Platinum, Titanium, Stainless steel other alloys etc. In another embodiment of the invention, the coating of the metallic electrode is done by the conventional electrochemical methods. In yet another embodiment of the invention, the reference electrode used is such as Calomel electrode, Ag/AgCI electrode or any commercially available standard electrode. In yet another embodiment of the invention, the means used for measuring the-potential difference may be such as Voltmeter, distal display meter or even a computer etc. The invention is further illustrated with the help of the following examples 1 & 2 and therefore should not be construed to limit the scope of the present invention in any manner. Example 1: Polycarbazole based Cu (II) ion sensor The electrochemical polymerization of carbazole was carried out in dichloromethane (CH2Cl2) containing 0.1 M Tetra butylammonium perchlorate (TBAP) and 60 mM carbazole by sweeping potential between -0.2 to 1.5 V vs Ag/AgCI or at the constant potential of 1.4 V vs Ag/AgCI or at the constant current of 0.5 mA/cm2 over a metallic electrode. The electropolymerized film was washed in CH2Cl2 and subsequent in THF and reduced in the same monomer free electrolyte. The polycarbazole modified electrode was then incubated overnight in 1 M KCI. The ion-sensor together with a double junction reference electrode (with cell assembly Reference electrode/KCIsat/0.1 M NH4NO3/test solution/sensor electrode) was dipped in the stirred electrochemical cell with a working volume of 15 ml of 0.1 M tris HCI buffer (pH 7). The electrode potential was monitored with an Orion pH model SA 520 meter and recorded with an Omniscribe series x-t recorder (model 2000). At the steady-state potentiometric response, varying concentrations of the Cu (II) ion solution was injected into the cell and the new steady-state potential was recorded as shown in the graph 1. A slope of 99.4 mV/decade was calculated within the marked arrow. Sensor electrode was found to be very stable for several sets of measurements. Interference of Na+, NH4+, Ni*2 , Co+2, Zn+2, Pb+2, Cu+ etc. cations and CI", NOs", CIO4", SU42 etc anions were also studied and sensor was found to be very selective for copper (II) ions only except for Pb+2, Cu+ ions which show very little sensitivity however it can not full fill the critical crateria of commercially available sensor. Example 2 : Polyindole based Cu (II) ion sensor The electrochemical polymerization of polyindole was carried out in containing 0.1 M TBAP at constant potential of 1.0 V vs. Ag/AgCI or by sweeping potential between -0.2 to 1.1 V vs Ag/AgCI or at the constant current of 0.3 mA/cm2 over a metallic electrode same as described above in examplel for polycarbazole. The electropolymerized polyindloe , modified electrode was washed in dichloromethane and subsequent in THF. The polymer modified electrode was electrochemically reduced and then incubated overnight in 1 M KCI. The potentiometric responses of the ion-sensor constructed above are carried out in 0.1 M tris HCI buffer (pH 7) using a double junction Ag/AgCI electrode. The ion-sensor together with a double junction reference electrode was dipped in the stirred electrochemical cell with a working volume of 15 ml of 0.1 M tris HCI buffer (pH 7). The electrode potential was monitored with an Orion pH model SA 520 meter and recorded with an Omniscribe series x-t recorder (model 2000). At the steady-state potentiometric response, varying concentrations of the ionic solution was injected into the cell and the new steady-state potential was recorded as shown in the graph 2. A slope of 140 mV/decade was calculated within linear range of the plot. Sensor electrode was found to be very stable for several sets of measurements. Interference of Na+, NtV, Ni+2 , Co+2, Zn+2, Pb+2, Cu+ etc. cations and CP, N03- , CIO4, SO-2 etc anions were also studied and sensor was found to be very selective for copper (II) ions only except for Pb+2, Cu+ ions which show very little sensitivity however it can not full fill the critical crateria of commercially available sensor. The main advantages of the present invention are: The main advantages of the present invention are: 1. Ion sensing is observed using single layer of neutral conducting polymer film, 2. Simple configuration of Cu++ selective electrode, 3. Analysis of Cu++ ion which are important from industrial and pollution control view, 4. Occurrence of constant steady-state potential. 5. Detection limit is up to 1.9x10-4 M of copper (II) ion concentration. 6. Cu(ll) sensors are stable up to very long time period (> 3 months). 7. Slope of the polycarbazole based electrode and polyindole based electrode show supernernstian behaviour and is 99.4 mV/decade and 140 mV/decade respectively which is a novelty of new Copper (II) ion sensor. We Claim: 1. A device useful for sensing Copper (II) ion in fluids characterized by a novel solid state copper (II) ion sensor, and a reference electrode placed in a container for holding the fluid in which copper ion is to be detected, the potential outputs of the said electrode pair being connected to means such as herein described, for measuring potential difference which is the direct measurement of the copper (II) ion in fluids, the said novel solid state copper (II) ion sensor essentially consists of coating a metallic electrode such as herein described, with a single layer electroactive conducting polymer selected from polycarbazole, polyindole or its copolymers and derivatives, in neutral/undoped state and if desired, providing an insulating protective outer covering so as to allow fluid contact with the resultant electrode. 2. A device as claimed as claim 1 wherein a reference electrode used is selected from Calomel electrode, Ag/AgCI electrode or any commercially available standard electrode. 3. A device as claimed as claims 1 wherein the means used is selected from Voltmeter, distal display meter or a computer. 4. A device useful for sensing Copper (II) ion in fluids substantially as here in described with reference to the examples and drawings.

Documents:

806-del-1999-abstract.pdf

806-del-1999-claims.pdf

806-del-1999-correspondence-others.pdf

806-del-1999-correspondence-po.pdf

806-del-1999-description (complete).pdf

806-del-1999-drawings.pdf

806-del-1999-form-1.pdf

806-del-1999-form-19.pdf

806-del-1999-form-2.pdf