Dissolved CO2 Sensor

Inline CO₂ Monitoring for Biopharma and Fermentation

METTLER TOLEDO offers two industry-leading inline dissolved CO₂ sensor solutions to meet the demands of bioprocess and beverage production environments. The membrane-based InPro 5000i provides accurate low-range carbon dioxide measurement using the proven Severinghaus principle, making it ideal for cell culture and fermentation processes. For broader range applications, the InPro 5500i dissolved CO₂ sensor uses optical measurement technology to deliver fast, drift-free CO₂ readings with minimal maintenance.

Both sensors are compatible with CIP/SIP processes and equipped with Intelligent Sensor Management (ISM®) for predictive diagnostics and simplified calibration, helping improve process reliability and reduce downtime across R&D and production-scale operations.

METTLER TOLEDO Intelligent Sensor Management

METTLER TOLEDO’s InPro 5000i is a membrane-based sensor designed for precise inline measurement of dissolved carbon dioxide in biopharmaceutical applications. It uses the Severinghaus principle of potentiometric CO₂ detection — an industry-standard approach trusted for over 55 years.

This sensor is ideal for:

• Monitoring pCO₂ in mammalian cell culture and microbial fermentation
• Real-time control of CO₂ levels in bioreactors and closed-loop systems
• Applications requiring sterile, low-maintenance operation

Key benefits include:

• Fully sterilizable: supports CIP, SIP, and autoclave workflows
• High surface-finish stainless steel body to reduce contamination risk
• Durable membrane with simplified service—replacement takes minutes
• Replaceable internal pH electrode for easy onsite maintenance
• ISM® digital platform for predictive diagnostics and integration

The InPro 5000i helps ensure gas-phase balance and product quality in critical upstream processes while minimizing downtime and maintenance costs.

Dissolved CO2 Sensor InPro 5500i Varivent Type N

The InPro 5500i is a digital, optical dissolved CO₂ sensor designed for inline or immersion applications in biopharmaceutical, fermentation, and food & beverage processes. Built with METTLER TOLEDO’s Intelligent Sensor Management (ISM®) platform, this sensor series offers real-time CO₂ monitoring with predictive diagnostics and reduced maintenance.

The 5500i family includes three model variants optimized for different installation needs:

InPro 5500i/120/225: For immersion applications (e.g. open vessels, bypass loops)
InPro 5500i/225/425: Inline installation with extended reach
InPro 5500i/325/425: Inline installation with medium-length probe

All models deliver:

Wide CO₂ detection range: 0 – 20% vol (up to 200,000 ppm)
No electrolyte or recalibration required
Fast, drift-free measurement via optical fluorescence quenching
Digital ISM® interface for plug-and-measure simplicity and process reliability

The InPro 5500i is also ideal for food and beverage applications such as carbonation control in beer and soft drink production, where fast response and hygienic design are essential. With compatibility for sanitary process connections, this sensor supports clean-in-place (CIP) and sterilize-in-place (SIP) procedures—making it a strong fit for both regulatory compliance and process consistency.

This series is widely used for bioreactor control, cell culture monitoring, fermentation optimization, and inline CO₂ monitoring across R&D, manufacturing, and beverage production environments.

Note: The InPro 5500i is available in multiple process connection styles to suit different installation environments. All variants share the same measurement performance and ISM
diagnostics platform:

  • Tri-Clamp 2″ – sanitary clamp fitting
  • D28/M42 – 28 mm diameter with threaded cap nut
  • Varivent Type N – designed for Varivent process housings (shown below)
Measurement ParameterCarbon Dioxide
Measurement Range0…10 bar pCO₂, 0…15 g/L CO₂, 0…7 V/V CO₂
Measurement Range (PSI)0…145 psig pCO₂
Accuracy± 1% at ±5 °C of calibration temp; ±2% over 0–50 °C (32–122 °F)
Response Time21 s (measurement cycle time)
Measurement Cycle< 20 s
Measurement TechnologyThermal Conductivity
Temperature CompensationAutomatic with built-in RTD
Primary Media/ApplicationFood and Beverage
ISM (Digital) or AnalogISM (Digital)
Digital IntegrationRS485 – ISM
Wetted Metallic Material316L stainless steel
Surface RoughnessN5/Ra16 (Ra = 0.4 μm / 16 μin)
O-Ring MaterialEPDM
Wetted Membrane MaterialSilicone
Flow Requirements> 0.5 m/s
Autoclavable/SterilizableSterilizable Only
CIP ResistantYes
IP RatingIP 67
Hygienic/Biocompatibility ApprovalsFDA
Certificates & ApprovalsQuality certificate, Material certificate 3.1, Surface finish certificate
Measuring Temp. Range32 °F – 122 °F (0 °C – 50 °C)
Mechanical Temp. Range23 °F – 250 °F (-5 °C – 121 °C)
Operating Pressure (Bar)0–20 bar
Operating Pressure (PSI)Up to 362.6 psi
Design Pressure290 psi (20 bar)
Connector DesignStraight
Cable ConnectorM12, 5-pin
Process ConnectionVarivent Type N
Model FamilyInPro 5500i

mettler toledo ismWith Mettler-Toledo’s advanced Intelligent Sensor Management (ISM), these concerns are a thing of the past! ISM has been around for years helping all kinds of processes have accurate and assured calibrations and maintenance statuses throughout the whole line of Mettler-Toledo sensors. This technology sends you automatic diagnostic data about your sensor’s:

• Health • Dynamic lifetime • Calibration quality
• Glass strength • Sensor drift

Utilizing this technology would allow you to go into a run or experiment 100% certain that your probes will not be an issue and can move forward with peace of mind. By choosing one of the many Mettler-Toledo sensors equipped with ISM technology, you’ll save on manual labor, experimental waste/time, and be sure you won’t have experimental error due to sensor drift or misreading. With all of this, it makes it an easy choice to move towards ISM probes for your R&D lab or large-scale facility.

Which brings us to a really BIG announcement…

Mettler-Toledo recently launched ISM 2.0 which comes equipped with the same features described but with greater control, reliability, and software to bolster the ease of use and peace of mind that comes with these sensors. ISM 2.0 adds upgrades to the lifetime and calibration algorithms that make them even more accurate at telling you the health and quality of your data and sensors. The upgrade comes partnered with more robust software for enhanced process reliability.

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Call (650) 376-3837