The HEMOX ANALYZER is an automatic system for the recording of blood oxygen equilibrium curves and related phenomena. The recording can be performed in the association or dissociation modes, utilizing fresh whole blood or hemolysate. A recording can be performed with as little as 2 micro liter of blood, but for routine measurement it is best to use 30 to 50 micro liters.
The operating principle of the HEMOX ANALYZER is based on dual wavelength spectrophotometry for the measurement of the optical properties of hemoglobin and a Clark electrode for measuring the oxygen partial pressure in millimeters of mercury. The resulting signals from both measuring systems are fed to the X Y recorder or PC, which plots the resulting curve .
In the new Model B the blood sample (30 to 50 ul) is added to the HEMOX Solution or other buffer contained in a sample tube for transfer into the cuvette. The cuvette, which is an optical sample cell containing the oxygen electrode and thermistor probe, is mounted in a cuvette holder. Also contained in the ccuvette is a magnetic stirring bar for rapid stirring of the sample buffer mixture. The cuvette contains two (2) stoppers on the top, one of which is used for sample intake, while the other one supplies vacuum to the cuvette chamber. After the plotting of the curve, the sample is removed through the bottom outlet port to drain.
Front Panel Display
After the sample buffer solution has been drawn into the cuvette, the temperature of the mixture has to equilibrate until it has reached 37°C. Than the sample is oxygenated with air or oxygen, supplied from an outside air tank. After the sample has been completely oxygenated and the pO2 has been adjusted to the correct value, the ploting of the deoxygenation curve can begin by switching the AIR/NITROGREN switch to NITROGEN. The completion of the curve is reached when the pO2 approaches zero.
The time for completing the plotting of the curve is approximately 30 minutes but may be reduced by increasing the stirring speed and the flow of nitrogen. However, there are limitation to the plotting speed due to the saturation equilibrium between the photometric and the pO2 systems. The measurement is normally carried out at a temperature of 37°C to simulate physiological conditions. However, the temperature control system permits measurement at other temperatures in conjunction with the built in cooling coil connected to an external cooling bath (supplied by the customer).
The HEMOX Analyzer consists of the main console which is a sheet metal housing, upon the base of which the optical and electronic components are mounted. Also contained in the housing is the gas selection valve system and the pumping system for sample intake and removal.
The housing contains in its front section the optical bench with light source, lens system, cuvette holder and the photo multiplier detectors. The rear part of the housing contains the power supplies and the electronic chassis, including the four PC boards. The housing cover has a small hinged lid for easy access to the sample cuvette for sample loading and routine maintenance of the cavity and the pO2 electrode.
The complete top cover of the housing is hinged on the right side of the base and can be swung open by removal of two nuts, located under the base of the housing. All utilities, like main power, gases and optional cooling water, enter from the rear of the instrument. Also the main fuse (2.0 amps.) is located in the rear. All operational controls are front panel mounted for easy access and convenience of adjustment.