Method and apparatus for analyzing liquid

• US 4,293,307 A
• Filed: 03/15/1979
• Issued: 10/06/1981
• Est. Priority Date: 04/05/1978
• Status: Expired due to Term

• Current Assignee: Saint Peter's Research Trust Limited
• Original Assignee: Saint Peter's Research Trust Limited
• Inventors: Simpson, Roger J., Lawrence, C. Alexander, Gawthorpe, Janet A.
• Primary Examiner(s): Serwin, Ronald
• Application Number:
  US06/020,777
• Time in Patent Office: 936 Days
• Field of Search: 422/82, 422/81, 422/68, 422/101, 210/500 M, 204/195 P, 204/195 M, 23/230 B
• US Class Current: 436/150
• CPC Class Codes: G01N 33/4915 using flow cells flow cytometry G01N15/14

Abstract

Method and apparatus for analyzing a liquid such as blood, and in particular analyzing certain constituents such as potassium or calcium ions, or dissolved gases comprising withdrawing the constituents from the liquid into a carrier fluid, which may or may not be derived from the liquid itself and analyzing the carrier fluid. In this way, for example, the analysis apparatus is not contaminated by undesired constituents, such as protein molecules of the liquid under test.

Claims

1. Apparatus for continuously analyzing a continuous flow of liquid blood comprising

separation means for continuously separating from the blood at least part of the ions to be analyzed, said separation means including

a cell divided by a semi-permeable membrane into first and second compartments, the first compartment being connected to blood supply means to continuously receive blood therefrom and to means for continuous blood delivery, the semi-permeable membrane being of a type to allow the ions to be analyzed to pass continuously together with some water from the first compartment to the second compartment an anlyzer having at least one ion selective electrode and reference electrode, means for passing the water and ions continuously from the second compartment to said analyzer means, and means for measuring the potentials of the electrodes for determining the concentrations of the ions.

2. Apparatus, as claimed in claim 1, in which said means for supplying blood comprises a tube of non-toxic hypothrombogenic material.

3. Apparatus, as claimed in claim 1 or claim 2, in which said means for delivery of blood comprises a tube of non-toxic hypothrombogenic material.

4. Apparatus, as claimed in claim 1, in which said means to pass the water and ions to the analyzer means comprises a tube.

5. Apparatus, as claimed in claim 1, in which said semi-permeable membrane has a sharply defined molecular weight cut off point of 10,000 to 30,000 MW above which it will not permit passage of molecules.

6. Apparatus for continuously analyzing ions in a continuous flow of liquid blood comprising

separation means for continuously separating from the blood at least part of the ions to be analyzed, said separation means including

a cell divided by a semi-permeable membrane into first and second compartments, the first compartment being connected to blood supply means to receive blood continuously therefrom and to means for continuous blood delivery, the semi-permeable membrane being of a type to allow the ions to be analyzed to pass continuously from the first compartment to the second compartment and having a sharply defined molecular weight cut off point between 10,000 to 30,000 MW above which it will not permit passage of ions and molecules,

an analyzer means having at least one ion selective electrode and reference electrode, means for passing ions continuously from the second compartment to said analyzer means, and means for measuring the potentials of the electrodes for determining the concentrations of the ions.

7. Apparatus, as claimed in claim 6, including means for indicating blockage or rupture of the semi-permeable membrane.

8. Apparatus, as claimed in claim 7, in which said means to indicate membrane blockage or rupture comprises means to allow the water and ions after analysis to fall in drops, and means for detecting the interval between the drops.

9. Apparatus, for continuously analyzing blood comprising

means for continuously supplying blood,

means for delivery of the blood,

separation means connected to the withdrawing means for separating from the blood at least part of the constituents which are to be analyzed, said separating means including

a cell divided by two-semi-permeable membranes into first, second and third compartments, said first compartment being provided between the second and third compartments and being connected to said means for supplying blood to continuously receive blood therefrom and to the means for delivery of blood, the semi-permeable membrane between the first and second compartments being such as to allow ions to be analyzed to pass together with some water to the second compartment.

an analyzer means having at least one ion selective electrode and reference electrode,

means to pass the water and ions to said analyzer means, means for measuring the potentials of the electrodes for determining the concentrations of the ions, said semi-permeable membrane between the first and third compartments being such as to allow dissolved gases to pass into the third compartment,

a carrier gas supply connected to the third compartment,

a gas analyzer unit connected to the third compartment and comprising a cell having windows transparent to radiation of the required wavelength, means for passing radiation of that wavelength through the gas and through the windows, and means for analyzing the transmitted radition to determine the gases and concentrations present.

10. Apparatus, as claimed in claim 9, including means, for detecting a rupture of the semi-permeable membrane between the first and third compartments, comprising a transparent chamber, a radiation source, and a photodetector to check the transparency of the gas.

11. Apparatus, as claimed in claim 9 or claim 10, in which the carrier gas supply means includes means to provide a metered supply of carrier gas to the third compartment.

12. A method for continuously analyzing blood comprising, continuously supplying blood,

continuously separating from the blood by means of a semi-permeable membrane at least part of the ions to be analyzed with some water,

continuously analyzing the water and ions by means of at least one ion selective electrode and reference electrode and continuously measuring the potentials of the electrodes for determining the concentrations of the ions.

13. A method, as claimed in claim 12, in which the water and ions are passed to the analyzing means by means of a peristaltic pump.

14. A method for continuously analyzing blood comprising

supplying blood,

continuously separating from the blood at least part of the ions to be analyzed with some water,

continuously analyzing the water and ions by means of at least one ion selective electrode and reference electrode, and

continuously measuring the potentials of the electrodes for determining the concentrations of the ions, continuously separating at least part of the dissolved gases from the blood, and

continuously analyzing said separated dissolved gases by passing radiation through the gases and analyzing the transmitted radiation to determine the gases and concentrations present.