Appliance for measuring the ph value of biological fluids

Abstract

Abstract 725,586. Determining pH values electrically. NOYES, R. C. (Joos, B.). March 18, 1953, No. 7493/53. Class 37. [Also in Group VI] A glass electrode for making pH measurements under controlled temperature conditions comprises a long, thih-walled, narrow glass tube containing the test liquid, sealed into the glass electrode containing the buffer solution, so that the contents of the tube are at the known temperature of the buffer solution. As shown for determining the pH value of e.g. blood, a glass electrode comprises a main vessel 1 containing the buffer solution 2 and housing the glass diaphragm 4 sealed at its ends 5, 6. Extensions of the main vessel 1 carry the electrode terminal 7, and a thermometer 8. The wall of the diaphragm tube 4 is very thin, and the volume of buffer solution is at least 100 times the volume of test fluid, so that the temperature of the test fluid is rapidly adjusted to that of the surrounding liquid. The glass electrode is provided with suitable connections at the ends 9, 10 for receiving an intravenous syringe 11, having a needle end 11a, or, for exteriorly accessible sources of fluid, the syringe may terminate in a suction point for use with a socket 13 locally secured with adhesive plaster 14, and filled with fluid by pressing the surround. Alternatively the skin surface may be punctured by a spring lancet 17, to enable the socket 13 to be filled. To avoid contact between the fluid and the air, the duct of the socket 13 is coated with a sealing substance 18, e.g. paraffin oil. The main body of the glass electrode may be covered by a jacket filled with gas or evacuated, to provide heat insulation during handling, or the extensions on the main vessel 1 may be lateral to provide a handle 20 (Fig. 5) covered with insulating material 21.

Inventors

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