What is the difference between Manual Calibration and using delivered batch-calibration values for the PhoxyPlates? When do I apply which one and is a One Point Adjustment needed?

The Manual 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. We recommend to perform a OPA in both cases to account for well-to-well differences.

The Manual Calibration is used if the values measured with the delivered batch-calibration data set differ largely from the expected / known values. This can be the case if you work in temperatures largely differs from 37°C (where the batch pre-calibration is performed) or use complex samples, e. g. with strongly fluorescing or colored media, or ionic strengths strongly differing from 140 mM.

The One-Point Adjustment (OPA) adapts the global calibration data set for each sensor position to match 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 sensor position separately.