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What is the difference between User-Defined Calibration and One-Point Adjustment for the SDR? When do I apply which one?
The User-Defined Calibration is a multipoint calibration and requires the measurement of samples of known oxygen / pH value.
For oxygen this is done with a 2-point calibration at 0 % oxygen and a second oxygen value (e. g. 20.9 % oxygen).
For pH 6 solutions at different pH values are required. The procedure is described in detail in the Instruction Manual.
The result is a new Batch calibration data set created by the user. The User-Defined Calibration is used if the values measured with the Batch calibration data set differ largely from the expected / known values. This can be the case if you work in low temperatures (< 15 °C) or use difficult samples, e. g. strongly fluorescing media.
The One-Point Adjustment (OPA) adapts the measured value for each channel to a set (oxygen or pH) value. The set value must be known (e. g. 95 % air saturation for an incubator with 5 % CO2; pH measured with a pH electrode or given on the medium bottle). The One-Point Adjustment is used if the deviation between the values measured with the Batch calibration data set and the expected / known value is rather small. It also improves the well-to-well precision, as it is applied to each channel separately.