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96-well Microplates with Integrated Chemical Optical pH Sensors
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.
- For use with conventional fluorescence microplate readers
- High throughput screening
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|