96-well Microplates with Integrated Chemical Optical pH Sensors

HydroPlate HP96U

The HydroPlate HP96U is a beta-irradiated polystyrene 96-well round bottom microplate. A pH sensor is immobilized on the bottom of each well. The sensors are read out from the bottom side using a commercially available fluorescence reader and the approx. wavelengths 485/540 nm and 485/620 nm.

  • Ready-to-use
  • For use with conventional fluorescence microplate readers
  • High throughput screening
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pH Monitoring in Dairy Starter Cultures

In order to get good and reproducible quality of dairy products suitable starter cultures have to be used. HydroPlates are an easy-to-use method to screen a large number of inoculum cultures as quality control for raw materials. Differences in inoculum type and size of cultures of Lactococcus lactis and Streptococcus thermophilus can be clearly detected, even though there are disturbances caused by particles and fluorophores contained in the medium. The recorded pH values are quite close to values measured offline with a pH electrode.

G. T. John, et al., 2003, Saarland University + Danisco, Saarbrücken, Germany


* at 37 °C; performance dependent on the reader; provided constant ionic strength
Measurement range pH 5.0 - 8.0
Resolution* at pH = 7: ± 0.05 pH
Precision* ± 0.2 pH at pH = 7 (sensor batch calibration)
± 0.1 pH at pH = 7 (sensor spot calibration)
Drift* < 0.002 pH per hour (sampling interval 1 min.) at pH = 7
Measurement temperature range from + 15 to + 45 °C
Response time (t90)* < 30 sec.
Compatibility Aqueous solutions, ethanol (max. 10 % v/v), methanol (max. 10 % v/v), pH 2 - 10
Cross sensitivity Changes in ionic strength
Calibration Needs to be calibrated once per batch
Beta-irradiated; not re-usable
Plate type 96-well round bottom plates (Greiner Microlon® 600)
Working volume 30 - 280 µL (max. filling volume 300 µL)
Indicator filters 485 nm / 538 nm
Reference filters 485 nm / 620 nm

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