Calibration solution and calibration method for sensor
First Claim
1. A calibration solution for a sensor with a solid electrode for measuring ion concentration of a solution under examination, comprising a standard buffer solution which comprises a mixture solution of Na2 HPO4 and NaH2 PO4 in a 1 to 1 ratio, and with NaCl being added to said buffer solution to provide an ionic strength substantially identical with the ionic strength of said solution under examination.
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Accused Products
Abstract
A calibration solution, which is used when measuring the ion concentration of solution under examination such as blood or other body fluids using a pH sensor or the like ion sensor with a solid electrode, is prepared by adding NaCl to a standard buffer solution and thus setting the ionic strength of the solution to be substantially identical with the ionic strength of solution under examination. A sensor calibration method is also disclosed, in which at least two reference calibration solutions having different pH values are prepared, the electromotive force of the sensor in these calibration solutions is measured by immersing the sensor in the solutions, and a calibration formula is produced from the electromotive force for the pH values of the reference calibration solutions. A predetermined amount of bicarbonate buffer solution is added to the calibration solution to maintain a substantially constant ionic strength of the solution, thus permitting simultaneous calibration of an ion sensor and a gas sensor.
12 Citations
15 Claims
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1. A calibration solution for a sensor with a solid electrode for measuring ion concentration of a solution under examination, comprising a standard buffer solution which comprises a mixture solution of Na2 HPO4 and NaH2 PO4 in a 1 to 1 ratio, and with NaCl being added to said buffer solution to provide an ionic strength substantially identical with the ionic strength of said solution under examination.
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2. A calibration solution for a sensor with a solid electrode for measuring ion concentration of a solution under examination, comprising a standard buffer solution which comprises a mixture solution of Na2 HPO4 and NaH2 PO4 in a 4 to 1 ratio, and with NaCl being added to said buffer solution to provide an ionic strength substantially identical with the ionic strength of said solution under examination.
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3. A calibration solution for a sensor with a solid electrode for measuring ion concentration of a solution under examination, comprising a standard buffer solution, and with NaCl being added to said buffer solution to provide an ionic strength in the range of 0.08 to 0.18 which is substantially identical with the ionic strength of said solution under examination.
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4. A calibration method for calibrating an ion sensor comprising the steps of:
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setting an ionic strength which is substantially identical with the ionic strength of a solution under examination by adding NaCl to a standard buffer solution which comprises a mixture of Na2 HPO4 and NaH2 PO4 in a 1 to 1 ratio while preparing at least two reference calibration solutions having different pH values; measuring the electromotive force in each of said reference calibration solutions by immersing said sensor in each of said solutions; and producing a calibration formula from the electromotive forces with respect to the pH values of each of said reference calibration solutions.
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5. A calibration method for calibrating an ion sensor comprising the steps of:
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setting an ionic strength which is substantially identical with the ionic strength of a solution under examination by adding NaCl to a standard buffer solution which comprises a mixture of Na2 HPO4 and NaH2 PO4 in a 4 to 1 ratio while preparing at least two reference calibration solutions having different pH values; measuring the electromotive force in each of said reference calibration solutions by immersing said sensor in each of said solutions; and producing a calibration formula from the electromotive forces with respect to the pH values of each of said reference calibration solutions.
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6. A calibration solution for a sensor with a solid electrode for measuring the ion concentration of a solution under examination which comprises a standard buffer solution comprised mainly of a phosphate buffer which buffer is a mixture composed of Na2 HPO4 and NaH2 PO4, and with NaCl being added to said buffer solution to permit the solid membrane surface of said electrode to be held at equilibrium potential.
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7. A calibration solution for a sensor for simultaneously calibrating an ion sensor and a gas sensor, these sensors being provided with solid electrodes with respect to the ion concentration and dissolved gas concentration in solution under examination;
NaCl being added to said standard buffer solution to provide an ionic strength substantially identical with the ionic strength of solution under examination, a predetermined quantity of bicarbonate buffer solution being added to maintain the ion concentration substantially constant. - View Dependent Claims (8, 9, 10, 11)
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12. A calibration method for simultaneously calibrating an ion sensor and a gas sensor comprising the steps of:
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preparing at least two standard buffer solutions having different pH values and partial gas pressure values by adding NaCl for setting an ionic strength substantially identical with the ionic strength of solution under examination and also adding a bicarbonate buffer solution for stabilizing the pH value; measuring the electromotive forces of said ion and gas sensors in said reference calibration solutions by immersing said sensors in said solutions; and forming calibration formulas by plotting the electromotive forces of said ion gas sensors for the pH values and partial gas pressure values of said standard buffer liquids, respectively. - View Dependent Claims (13, 15)
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14. A calibration method for simultaneously calibrating a pH sensor, a carbon dioxide gas sensor and an oxygen gas sensor comprising the steps of:
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preparing at least two standard buffer solutions having different pH values, partial carbon dioxide gas pressure values and partial oxygen pressure values by adding NaCl for setting an ionic strength substantially identical with the ionic strength of solution under examination and also adding a bicarbonate buffer solution for stabilizing the pH value; measuring the electromotive forces of said pH and carbon dioxide gas sensors and also the current in said oxygen sensor in said reference calibration solutions by immersing said sensors in said solutions; and forming calibration formulas by plotting the electromotive forces of said pH and carbon gas sensors for the pH values and partial carbon dioxide gas pressure values of said reference calibration solutions and also forming a calibration formula by plotting the current value of said oxygen sensor for the partial oxygen pressure value.
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Specification