Non-Invasive pH Sensors
Pre-calibrated, ready-to-use & real conditions: Look into any transparent vessel
- Variety of disposables
- Bags & single-use bioreactors
- Micro-liter to production scale
The non-invasive pH sensors are optimized for physiological solutions and culture media. These sensor spots are mounted in transparent vessels made of plastics or glass for example. Plastic vessels with integrated pH sensors are ready-to-use as they are beta-irradiated and pre-calibrated. The pH is measured in a non-invasive and non-destructive manner from outside. They enable continous monitoring of pH without the need for at-line sampling.
Features
- Online monitoring without sampling
- Non-invasive & non-destructive measurement
- Pre-calibrated
- Integrated in beta-irradiated disposables
- Applicable for micro-liter scale to production scale
- Optimized for culture media and physiological solutions
Selected Probes
Sensor Spots
Sensor Spots (SP) are the most versatile version of non-invasive pH sensors. They are attached to the inner surface of any transparent vessel.
Examples are
- Shake flasks & spinners
- Tubes & petri dishes
- Cultivation bags
The transmitter with its optical fiber can be fixed opposite the sensor spot using our accessories (see our accessories brochure) which can be adapted for nearly all kinds of vessels.
Flow-Through Cell
The flow-through pH minisensor (FTC) is a miniaturized fiber chemical optical sensor integrated in a flow-through cell. It is connected to the transmitter by an optical fiber. The volume of liquid inside the FTC is about 250 microliters. The standard flow cell can be easily connected via Luer-Lock adapters to external tubing. The FTC is beta-irradiated and pre-calibrated.
Measurement Principle
The Patented Dual Lifetime Referenced (DLR) Method
The patented DLR method enables internally referenced measurements. A combination of different fluorescent dyes detects intensity changes in the time domain. It is essential for the pre-calibrated measurements and the easy parallelisation of measurement through the identical calibration of large numbers of sensor spots.
Examples for Applications
Pharma Industry: pH Monitoring in Bags
Bags and single-use bioreactors are in the process of revolutionising the way biopharmaceuticals are manufactured. Our non-invasive pH sensors are the tools to make the cultivation vessels fully disposable. As non-invasive DO sensors are also available, the two key parameters oxygen and pH can be controlled online.
Online Measurement in Perfusion Systems
Beta-irradiated and pre-calibrated pH and DO flow-through sensors can be integrated into perfusion systems. This allows easy control of process parameters in perfusion reactors. Typically Luer connectors are used, though different sizes for larger or smaller flow rates are available.
Bioprocess Development: pH Monitoring in Shake Flasks
The pH is one of the major issues in the cultivation of cells, yeast or bacteria. Shake flask cultures are widely applied in academic and industrial bioprocess development. As adequate methods for real monitoring of pH were not available, cumbersome at-line sampling was used. The combination with non-invasive oxygen sensors in shake flasks provides new insights into metabolic activity and changes in metabolic pathways.
Customized Micro Reactors and Ports
pH and DO sensor spots are mounted in customized micro reactors. They can be delivered beta-irradiated and pre-calibrated. Integration into a variety of polymeric surfaces is possible. Immobilisation on ports which are integrated into the reactors at the customer's facilities is a second application.
Transmitters & Accessories
pH-1 mini
Fiber optic pH transmitter for use with non-invasive pH sensors.
pH-4 mini
4-channel fiber optic pH transmitter for use with non-invasive pH sensors.
pH-10 mini
10-channel fiber optic pH transmitter for use with non-invasive pH sensors.
Coaster CFG
The coaster CFG is used for shake flasks.
SOA Adapter
The stick-on adapter SOA is used for transparent vessels with planar surface.
ARC Adapter
The adapter for round containers ARC is used for spinner flasks or similar vessels.
Brochures incl. Tech. Data
FAQs
- Which side of the sensor spot should face the medium?
- Which substances can interfere with the measurement?
- Do the sensors work in turbid solutions?
- Is the glue or the spot biocompatible - which tests were done? Are there any studies on leachables and extractables?
- Which glue can I use?
- How can I clean non-invasive pH sensors?
- Can I use Ethanol for disinfecting non-invasive pH sensors?
- How to prepare buffers of constant ionic strength and calibrate optical pH sensors?
- Why does my pH sensor not work in tap water?
- Where do I need sensor spot sizes different from the common diameter of 5 mm (approx. 0.2 inch)?
- In which vessel can I integrate a sensor spot?
Software
- pH-1 mini version 1.1.0 - Windows XP/Vista/7
- pH-4 mini version 1.07 - Windows XP/7
- pH-10 mini version 1.06 - Windows XP/Vista/7
- USB Serial Driver - Windows XP/Vista
Media
Application Notes
- pH Regulation for a Liver Cell Bioreactor: Prototype development with a chemical optical pH flow-through cell
- Validation Study of the Optrode Dual: Oxygen and pH Measurements in a Single-Use Bioreactor with Integrated Optical Sensors Using a Conventional Controller
- Optrode Dual Connects Single-Use Bioreactors to Conventional Controllers: Monitoring of CHO Cell Cultivation with Chemical Optical Sensors
Recent Scientific Publications
- Combination of On-line pH and Oxygen Transfer Rate Measurement in Shake Flasks by Fiber Optical Technique and Respiration Activity MOnitoring System (RAMOS)
- Wurzelexsudation in der Wasserfluktuationszone des Drei-Schluchten-Reservoirs, VR China. Ein Ansatz für Einblicke in eine überflutungsgestresste Rhizosphäre am Beispiel von Salix variegata Franch
- Rhizosphere pH dynamics in trace-metal-contaminated soils, monitored with planar pH optodes
- Fully automated single-use stirred-tank bioreactors for parallel microbial cultivations
- New Milliliter-Scale Stirred Tank Bioreactors for the Cultivation of Mycelium Forming Microorganisms


