Automatic analyzer

• US 3,997,420 A
• Filed: 02/18/1975
• Issued: 12/14/1976
• Est. Priority Date: 03/18/1971
• Status: Expired due to Term

• Current Assignee: Beckman Instruments, Inc. (Danaher Corporation)
• Original Assignee: Beckman Instruments, Inc. (Danaher Corporation)
• Inventors: Buzza, Edmund E.
• Primary Examiner(s): Tung, T.
• Application Number:
  US05/550,271
• Time in Patent Office: 665 Days
• Field of Search: 204/1 T, 204/195 R, 204/195 P, 204/195 F, 204/195 G, 204/195 M
• US Class Current: 204/411
• CPC Class Codes: G01N 33/4925 measuring blood gas content, e.g. O2, CO2 , HCO3

Abstract

An apparatus for automatically performing blood chemistry analyses and in particular the determination of the pH, PCO₂ and PO₂ of blood. The apparatus employs a flow cell having pH, PCO₂ and PO₂ measuring electrodes mounted therein adjacent to a sample passage extending through the cell. Sample is collected in a conventional syringe. The needle of the syringe is removed and the syringe cylinder is attached to the flow cell adjacent to the inlet end of the sample passage. Means are provided for automatically driving the plunger of the syringe into the cylinder to convey the sample through the sample passage. A wash solution is then conveyed through the passage to discharge the sample therefrom and thereafter a calibration solution is conveyed through the passage which permits simultaneous calibration of the pH, PCO₂ and PO₂ electrodes. A unique construction of the flow cell and means for mounting the measuring electrode therein allows the use of a single reference electrode which is common to each of the measuring electrodes. Means are also disclosed for allowing flushing of a capillary passage in the flow cell which forms a liquid junction between the reference electrode and the sample in the sample passage.

Claims

1. A flow cell assembly containing ion measuring and gas sensitive sensors for electrochemical analyses, said assembly comprising:

a body of insulating material having a sample passage extending therethrough;

an ion measuring electrode mounted in said body and having an ion sensing end positioned to contact sample flowing through said passage;

a gas sensitive electrode including a sensing end mounted in said body and a gas permeable essentially ion impermeable membrane separating said sensing end from sample flowing through said passage, said membrane being spaced from said sensing end to provide therebetween an electrolyte film space;

a reservoir containing a reference electrolyte for said gas sensitive electrode;

electrolyte communicating passages between said reservoir and said film space and said sample passage; and

an electrode mounted in said reservoir, said last mentioned electrode combining with said ion measuring electrode to define said ion measuring sensor and combining with said gas sensitive electrode to define said gas measuring sensor in said assembly.

2. A flow cell for electrochemical analyses comprising:

a body of insulating material having a sample passage extending therethrough;

a reference electrode in electrolytic contact with sample flowing through said passage and also in electrolytic contact with one or more electrolyte solutions each separated from said sample by a gas permeable essentially ion impermeable membrane;

one or more ion measuring electrodes in contact with said sample; and

a gas measuring electrode in each of the electrolyte solutions separated from said sample by an associated membrane, each gas measuring electrode being spaced from the associated membrane to provide an electrolyte film space therebetween.

3. A flow cell assembly comprising:

a body of insulating material having a sample passage extending therethrough;

a potentiometric-type gas measuring sensor and a polarographic-type gas measuring sensor for measuring different gases flowing in said sample passage and each including and sharing a common reference electrode mounted in a reservoir containing a reference electrolyte comprising a combination of electrolytes for said potentiometric and polarographic sensors, said potentiometric sensor further including a hydrogen ion sensitive electrode mounted in said body and a gas permeable essentially ion impermeable membrane separating a sensing end of said hydrogen ion sensitive electrode from sample flowing through said passage, said membrane being spaced from said sensing end to provide therebetween an electrolyte film space, and said polarographic sensor further including a metal cathode mounted in said body and a separate gas permeable essentially ion impermeable membrane separating a sensing end at said metal cathode from sample flowing through said passage, said separate membrane being spaced from said sensing end of said metal cathode to provide therebetween a separate electrolyte film space; and

electrolyte communicating passages between said reservoir and said film spaces and said sample passage.