Dissolved CO2 Systems

Dissolved CO2 (DCO2) Systems are designed to measure dissolved pCO2 in water at atmospheric pressure.  The systems are composed of a DCO2 sampler with accessories, a non-dispersive infra red CO2 analyzer with a built in gas pump, data interface and software. The Rapid Response DCO2 System consists of flow through Rapid DCO2 Sampling System, liquid pump, IRGA with built in gas pump, data interface and software.

The DCO2 sampler is the key component of the standard system as it samples pCO2 from the liquid and carries it to the IRGA.  The DCO2 sampler is  covered with  PTFE (polytetrafluoroethylene) membrane which allows it to be submerged in water (up to 2 ft).  The CO2 gas dissolved in water diffuses across the PTFE membrane into the sampler and is carried to the CO2 analyzer in a closed loop fixed volume gas stream for detection.  Liquid flow past the sampler is necessary and stirring is required for the system to work well.  A Rapid Response DCO2 System with a flow-through design is also available.  It employs the DCO2 sampling system where water is circulated through silicone tubules and gas passess on the other side of the tubules in the opposite direction.  CO2 gas then diffuses across the tubules from water to the gas stream and is carried to the CO2 sensor for measurements.

The PTFE membrane is permeable to gases but not to water at atmospheric pressure.  The system detects dissolved partial pressure of CO2 in water and is insensitive to carbonates.  Note that this determination of CO2 partial pressure is not based on pH measurements.   The DCO2 Systems can be configured for various ranges of CO2 concentrations from ppm to 100% in gas phase.

Note that the response time of the standard system is slow (4-10 min) due to diffusion across the PTFE membrane.  The response time depends on the flow of the liquid past the DCO2 sampler, hence good stirring of the solution is essential.  The response time of the flow-through Rapid DCO2 System is faster 2 to 4 min.

  • Measure dissolved CO2 in fresh and seawater
  • Customized to desired pCO2 range (ppm to 100%)
  • Based on diffusion of CO2 out of the liquid
  • Based on infrared gas analysis
  • Insensitive to carbonates
  • NOT based on pH measurements
  • Ocean Acidification Studies
  • Fermentation Studies
  • Algal Cultivation (Bioreactors)
  • Aquaculture
  • Environmental Monitoring
  • Waste Water Management
  • Food and Drink Industry
  • Aquatic Animal Respirometry (Rapid Response System)

Included with the Standard DCO2 System:

  • CO2 Analyzer with built in pump (S157-P for 0-2000ppm range or S158-P for 0-10% range) (custom ranges also available)
  • dCO2 Sampler with Accessories (S350) (tubing, Nafion RH equilibrator, PTFE filter, connectors, PTFE sleeve)
  • Two diffusers for setting up calibration water baths
  • Flow Meter (F100) for setting the gas flow through the system.
  • Data acquisition interface LabQuest Mini (C610)
  • Logger Pro software (C901)
  • Custom Set up files (C404)
  • Temperature sensor (S132)

Included with the Rapid Response DCO2 System:

  • CO2 Analyzer with built in pump (S157-P for 0-2000ppm range or S158-P for 0-10% range) (custom ranges also available)
  • Rapid DCO2 Sampling System (S400)
  • Liquid Pump 1LPM (PL175)
  • Two diffusers for setting up calibration water baths
  • Flow Meter (F100) for setting the gas flow through the system.
  • Data acquisition interface (C610)
  • Logger Pro software (C901)
  • Custom Set up files (C404)
  • Temperature sensor (S132)
  • DCO2 System accessory kit (tubing, connectors PTFE filters, Nafion RH equilibrator)

Optional sensors such as pH, salinity, dissolved O2 can also be included in the DCO2 System for monitoring of other parameters that may be complementary to dissolved CO2.

DCO2 Sampling System
Rapid DCO2 Sampler System

Software

Sample respirometry data from small gold fish using Rapid Response DCO2 System
Sample data from standard DCO2 System.

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