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Blood Gas Electrolyte Analyzer
- Sep 04, 2018 -

Blood gas analyzer: Medical equipment for blood testing, generally including electrodes (pH, PO2, PCO2), sample chamber, CO2 air mixer, amplifier components, digital operation display and printer. It has the advantages of quick and convenient detection, wide range and so on.


Features: automatic calibration, automatic injection, automatic detection and fault self-diagnosis, easy to operate, fast analysis and high accuracy.

Working principle: Under the negative pressure suction of the pipeline system, the sample blood is sucked into the capillary, and is in contact with the pH reference electrode on the capillary wall, pH, PO2, PCO2, and the electrode will measure the parameters. It is converted into its own electrical signals, which are amplified and analog-digital converted and sent to the microcomputer of the instrument. After the operation, the measurement results are displayed and printed (see figure), thus completing the whole detection process.

Instrument structure: mainly composed of three parts: electrode system, pipeline system and circuit system.

1. Electrode system: The electrode measuring system includes a pH measuring electrode, a PCO2 measuring electrode, and a PO2 measuring electrode. (1) The pH measuring electrode is a glass electrode consisting of an Ag-AgCl electrode and an appropriate amount of buffer solution. The membrane potential is used to determine the H concentration in the solution. The reference electrode is a calomel electrode, which serves to provide a reference potential for the pH electrode. . (2) The main structure of the PCO2 measuring electrode is a gas-sensitive electrode. The key is the single-permeability permeable membrane of CO2 molecules at the top of the electrode. The pH value is measured and the PCO2 value is obtained by logarithmic transformation. (3) The PO2 measuring electrode is based on the principle of electrolytic oxygen. It consists of a Pt-Ag electrode. Under the action of the gas permeable membrane, a certain voltage is applied externally, and O2 in the blood is reduced at the Pt cathode, and a stable electrolysis current is formed. The PO2 in the blood sample is determined by measuring the change in the current.

2. Piping system: It is a key part for setting up functions such as automatic calibration, automatic measurement, and automatic flushing.

3. The circuit system is mainly for the amplification and analog-to-digital conversion of the instrument measurement signals, display and print results. In recent years, the development of blood gas analyzers has been reflected in the upgrading of circuit systems, and the automated analysis process has been completed under the execution of computer programs.