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Respirometry
Respirometry is the determination of the gas metabolism of organisms (vertebrates, invertebrates, plants, tissues, cells or microorganisms). The measurements of oxygen uptake (MO2) and carbon dioxide release (MCO2) can be used to calculate the organisms' metabolic rate.
The energy contained in food molecules becomes available to an organism when the molecules or their derivatives are subject to oxidation. The aerobic degradation of substances requires a constant supply of sufficient amounts of oxygen. Respiration is essential to all living organisms.
Respirometry can be applied at all scales, from microorganisms to large animals, and in different areas like basic biological or medical research, environmental studies or wastewater treatment.
Respirometry requires reliable sensor technology and optical sensors have several properties that make them ideally suited for respiration measurements:
- Non-invasive measurement in closed chambers
- Measurements in liquid & gas phase
- No anlayte (O2) consumption during the measurement
- Signal independent from flow rate
- Flexibility in format and size of vessel
Closed Respirometry
In closed respirometry the organism(s), cell(s) or tissue is placed in an air-tight respirometry chamber filled with water or air. In the chamber, the amount of consumed oxygen and released carbon dioxide can be measured over a certain time period.
PreSens non-invasive sensors are ideally suited for measurements in closed systems. The respirometry chambers needs no further openings to insert the sensor, as the sensor read-out can be done through the chamber wall. Furthermore, we offer special glass vessels with integrated sensors and screw caps with septum. Thus, precise respiration measurements with small organisms can be conducted in those SensorVials. In contrast to oxygen electrodes, optical oxygen sensors do not consume oxygen during the measurement, which would falsify the respiration measurements. Multi-channel readers like the SDR SensorDish® Reader or the OXY-4 SMA allow analyzing many small-sized respiration chambers simultaneously.
Open Respirometry
In open or flow-through respirometry, air or water flows through the respiration chamber and the partial pressures of O2 or CO2 at the in- and outlets are measured. The difference in concentrations can be used to calculate the respiratory gas exchange. When using this method, it is important that the water or air inside the chamber is thoroughly mixed, so the water / air leaving the chamber is in equilibrium with the medium inside the respirometry chamber.
PreSens offers several sensor solutions for measurement in open respirometry systems. Oxygen sensors with a very fast response time can be used to monitor changing oxygen uptake online. Flow-through cells with integrated sensors can be integrated in flow-paths and used to measure simultaneously at the chamber's in- and outlet. No matter the scale, even if you measure in a large tank, PreSens can provide fast and reliable sensors for your respirometry set-up.
Take a look at different measurement set-ups on the next tab or contact our service team to discuss your application in detail.
Dedicated Measurement Systems for Closed Respirometry of Small Organisms
PreSens offers several measurement solutions specifically developed for respirometry of small aquatic organisms. SensorVials have an oxygen sensor spot or sensor stripe attached to the inner wall and are offered in different sizes, from 2 mL to 20 mL. Integration in customized vessels is also possible. The optical sensors can be read out non-invasively from the outside without having to open the vessel.
SensorVials, Sensor Spots and the SDR SensorDish® Reader
- SDR SensorDish® Reader + MSV-24 + SensorVials (2 mL or 4 mL)
SensorVials of 2 mL or 4 mL volume with integrated sensor spot SP-PSt5 can be placed on the SDR SensorDish® Reader. Oxygen measurements are taken non-invasively through the bottom of the vial, ensuring no oxygen ingress from ambient air. This set-up allows to measure respiration in up to 24 samples simultaneously. For easy positioning, the 24 vials are placed in an empty 24 well plate (scope of supply). Using a black holder, which shields the reader's optics from artifical light, this set-up can be used for photosynthesis measurements as well.
Products information
- SDR SensorDish® Reader + SP-PSt5 + (Spot integration & customization service)
The senor spots SP-PSt5 are also available separately, so they can be integrated in customer specific vessels. This way respirometry chambers with volumes of up to 100 mL can be created and measured with the SDR. Using bigger vials, up to 12 samples can be analyzed simultaneously with one SDR. If necessary, holders for these special vials can be produced on request.
Products information
SensorVials, Sensor Spots and Fiber Optic Oxygen Meters
- OXY-1 SMA + Polymer Optical Fiber + Vial Adapter + SensorVial + PreSens Measurement Studio 2
PreSens offers 20 mL SensorVials with integrated sensor stripes. The sensor stripes allow to read the oxygen content at different depths in the vial or simultaneously in liquid and gas phase without opening the vessel. Vials for use with a magnetic stirrer are also available, in which the sensor stripe does not reach all the way to the bottom.
The sensor stripe is read out from the outside via a polymer optical fiber, which is attached to a compact oxygen meter. A vial adapter can be used to hold the fiber in position opposite the sensor stripe. It is also possible to use one or several of our multichannel oxygen meters, like e.g. the OXY-4 SMA, and measure at several positions at once in one vial. You can follow the oxygen development online on all channels with the PreSens Measurement Studio 2 software.
Products information
- OXY-1 SMA + Polymer Optical Fiber + O2 Sensor Spot + PreSens Measurement Studio 2
Sensor spots for different measurement ranges can be integrated into any transparent glass or plastic vessel / tank before it is closed for respiration measurements. The oxygen measurements are taken non-invasively from the outside via polymer optical fiber. The fiber is connected to a small oxygen meter, which is controlled by the PreSens Measurement Studio 2 software. The software allows to control multiple oxygen meters, so measurements in different vessels or at different positions in one vessel can be followed online on one PC.
Products information
Oxygen Measurement Solutions for Open Respirometry
PreSens offers several sensors that can be integrated in the flow path of an open respirometry system.
Flow-through Cells with Integrated Sensors and Fiber Optic Oxygen Meters
Flow-through cells with integrated sensors are available in different sizes. They can be integrated in tubes (FTC-PSt3) or metal pipes (FTM-M10-PSt3) at the respirometry chamber's in- and outlet. The oxygen sensor inside the flow-through cell is read out contactless with a polymer optical fiber, which is connected to a small oxygen meter. The PreSens Measurement Studio 2 software allows to control multiple oxygen meters and you are able to follow the oxygen development at the in- and outlet of your chamber online.
- OXY-1 SMA + Polymer Optical Fiber + O2 Flow-through Cell FTC-PSt3 + PreSens Measurement Studio 2
This set-up is suitable for integration in tubes at the respirometry chamber's in- and outlet.
Products information
- OXY-1 SMA + Polymer Optical Fiber POF-SCT + O2 Flow-through Cell FTM-M10-PSt3 + PreSens Measurement Studio 2
This set-up is suited for integration in metal pipes at the respirometry chamber's in- and outlet.
Products information
Oxygen Microsensors and Fiber Optic Oxygen Meters
- OXY-1 ST + Needle-type O2 Microsensor NTH-PSt7 + PreSens Measurement Studio 2
Another solution that can be implemented in larger set-ups is to install PreSens' needle-type microsensors in the flow-path. These sensors are integrated in a syringe housing and have very fast response time. Integrated in the flow path of your respirometry chamber you will be able to see changes in oxygen levels immediately.
Products information
OEM Solutions and Customization for Respirometry
PreSens offers several oxygen measurement solutions that can be integrated in existing control and measurement units for respiration monitoring. Small electro-optical modules can easily be installed in housings and robust stainless steel probes can be connected directly to controllers. Another option is the wireless OXYBase® Blue oxygen measurement system, which can be controlled from your smartphone via Bluetooth connection. We also offer sensor engineering services, so if you need a special measurement solution, please do not hesitate to contact us!
