Sodium ion-selective electrode system and method for making an ion-selective electrode
First Claim
1. An arrangement for monitoring concentration of sodium ions in a fluid, the arrangement comprising:
- elongated body means having a lumen therein;
porous ceramic means arranged at one end of said elongated body means for closing said lumen of said elongated body means;
ion-selective membrane means for covering at least a portion of said porous ceramic means outside of said lumen of said elongated body means, said ion-selective membrane means being formed of N,N'"'"'-dibenzyl-N,N'"'"'-diphenyl-1,2-phenylenedioxydiacetamide suspended in a substantially inert vehicle; and
sensor electrode means arranged in said lumen of said elongated body means and arranged in the vicinity of said porous ceramic means for detecting a potential.
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Accused Products
Abstract
A sensor arrangement for monitoring ionic concentrations in fluids uses anion-selective membrane formed of N,N'"'"'-dibenzyl-N,N'"'"'-diphenyl-1,2-phenylenedioxydiacetamide suspended in an inert carrier, such as PVC having a high molecular weight. The membrane is disposed on a porous ceramic plug which permits wetting of the side of the membrane facing the plug with an internal fluid of the system, such as saline. The other side of the membrane communicates with the fluid to be assayed, which in certain intravenous embodiments may be the blood of a patient. In one embodiment, the system is provided with a reference electrode which is arranged to communicate with the fluid being monitored via a dialysis membrane. High impedance electronic circuitry produces a signal indicative of the ionic concentration in response to a potential appearing across the reference and sensor electrodes. The electronic circuitry has wide range offset and gain controls which are independent of one another, while maintaining the circuitry simple and safe for connection to a patient.
22 Citations
20 Claims
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1. An arrangement for monitoring concentration of sodium ions in a fluid, the arrangement comprising:
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elongated body means having a lumen therein; porous ceramic means arranged at one end of said elongated body means for closing said lumen of said elongated body means; ion-selective membrane means for covering at least a portion of said porous ceramic means outside of said lumen of said elongated body means, said ion-selective membrane means being formed of N,N'"'"'-dibenzyl-N,N'"'"'-diphenyl-1,2-phenylenedioxydiacetamide suspended in a substantially inert vehicle; and sensor electrode means arranged in said lumen of said elongated body means and arranged in the vicinity of said porous ceramic means for detecting a potential. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of forming an ion-selective membrane, the method comprising the steps of:
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combining N,N'"'"'-dibenzyl-N,N'"'"'-diphenyl-1,2-phenylenedioxydiacetamide with a plasticizer in a substantially airtight container to form a mixture; adding dissolved PVC to said first mixture to form a second mixture; evaporating said second mixture to increase its viscosity; and casting said viscous second mixture onto a porous member to form the ion-selective membrane. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A system for monitoring sodium ion concentration in a fluid, the system comprising:
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a sodium-ion-selective membrane having a first side for communicating with the fluid and a second side for communicating with a first internal fluid of the system, said sodium-ion-selective membrane being formed of N,N'"'"'-dibenzyl-N,N'"'"'-diphenyl-1,2-phenylenedioxydiacetamide suspended in an inert carrier; a sensor electrode for communicating with said first internal fluid; a reference electrode for communicating with a second internal fluid of the system; further membrane means having a first side for communicating with said second internal fluid of the system and a second side for communicating with the fluid being monitored; and monitoring means having first and second input terminals for communicating electrically with said sensor and said reference electrodes, respectively, and for producing an output signal responsive to a potential across said first and second input terminals, said monitoring means having a gain characteristic and a voltage offset characteristic, said characteristics each being adjustable independently of one another. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification