Oxygen sensor spot protocol

For Oxygenscan option only

Background

In the Oxygenscan, the oxygen level in the sample is measured through the luminescence quenching of a luminophore spot. When the luminophore spot is illuminated by a green/blue light, it reacts by returning orange light. When the green/blue light is switched off, there is a decay time of the returning orange light. The decay time is dependent on the temperature and oxygen level in contact with the luminophore spot, referred to here as the partial oxygen pressure (pO2) sensor spot.

The pO2 at sea level is approximately 149.3 mmHg at 37°C. In the Lorrca, a new pO2 sensor spot will show an equilibrium pO2 of about 149 mmHg. For improved accuracy, each batch of sensor spots is accompanied by calibration data. The response of the sensor from ambient oxygen to no oxygen is not all linear along this trajectory and can vary between different production batches of the sensor spot. The calibration data is the input for the formula to correct for this non-linearity. Beside this correction, over time, the pO2 measured by the spot will decline due to the influence of light and mechanical wear, resulting in an inaccurate reading of the real ambient pO2.

Correcting the decline in the pO2 measurement

See chapter Self-check.

Checking and replacing the pO2 spot

The user should perform a pO2 self-test during each start-up of the instrument to check the pO2 measurement before using the Oxygenscan. If the pO2 sensor spot measures an ambient pO2 of less than 130 mmHg, the wear of the spot is considered too high and should be replaced with a new one. See Replacement sensor-spot.