Quantek CO₂ Analyzer for incubator spot checks

CO₂ measurement in incubators is an important consideration in cell-culture environments where carbon dioxide concentration is used to maintain controlled culture conditions. In bicarbonate-buffered media, the CO₂ concentration in the incubator atmosphere contributes directly to the equilibrium that determines the pH of the culture medium.

For laboratories that need to perform independent spot checks of incubator CO₂ levels, the Quantek Q21 Portable CO₂ Analyzer provides a portable measurement solution. Quantek specifically identifies the Q21 for CO₂ measurements in incubators and bio-enclosures, making this application a manufacturer-confirmed use case rather than an extrapolation from the instrument specifications.

At a glance

Why does CO₂ measurement matter in cell-culture incubators?

In many mammalian cell-culture applications, incubators maintain an atmosphere containing a controlled concentration of carbon dioxide. This CO₂ is particularly important when the culture medium uses a CO₂-bicarbonate buffering system.

Dissolved CO₂ and bicarbonate interact to help maintain the required pH of the culture medium. A change in atmospheric CO₂ can therefore alter this equilibrium and cause the medium pH to shift.

The appropriate CO₂ concentration is not universal. It depends on the culture medium formulation, bicarbonate concentration and experimental protocol. For this reason, the incubator setpoint should always follow the requirements of the medium and the cell-culture procedure rather than a generic CO₂ value.

Where is controlled CO₂ used?

Controlled CO₂ atmospheres are commonly associated with cell-culture incubators used in laboratory and research environments. They are particularly relevant when cells are grown in open or gas-permeable culture vessels using bicarbonate-buffered media.

Depending on the research protocol, controlled CO₂ conditions may be encountered in:

• Mammalian cell culture
• Cell and tissue research
• Research laboratories using CO₂ incubators
• Bio-enclosures requiring CO₂ spot measurements

An external CO₂ analyzer does not define the correct atmosphere for these applications. Its role is to provide an independent measurement of the gas concentration present at the selected sampling point.

Why perform an independent CO₂ spot check?

A CO₂ incubator already contains its own sensor and regulation system. An external analyzer therefore serves a different purpose: it can provide an independent spot measurement of the chamber atmosphere.

Depending on laboratory procedures, an external measurement can be useful when users want to:

• Perform a routine spot check of incubator CO₂ concentration
• Compare an independent measurement with the incubator display or setpoint
• Check multiple incubators using a portable instrument
• Record measurements for subsequent data review

The Q21 should therefore be considered a measurement instrument rather than a control device. It does not regulate gas injection or replace the incubator's internal CO₂ sensor.

What are the challenges of measuring CO₂ in an incubator?

Incubator CO₂ measurement presents several practical issues that should be considered when performing an external spot check.

High humidity and condensation

Cell-culture incubators commonly maintain a high-humidity environment. Quantek specifies that the gas introduced into the Q21 should be clean and dry, with no condensation. A PTFE filter can be fitted to the sampling probe to help protect the instrument from moisture and particulates, but condensation should not be drawn into the analyzer.

Disturbing the chamber atmosphere

Opening an incubator introduces room air and temporarily changes its internal atmosphere. Where the incubator provides an appropriate sampling port, extracting the sample through tubing can avoid opening the chamber solely to carry out a measurement.

Sampling line and measurement conditions

Sampling tubing, fittings and filters form part of the measurement chain. The configuration should be selected so that the gas reaching the instrument is representative of the chamber atmosphere and remains within the Q21 sampling requirements.

How does the Quantek Q21 measure CO₂?

The Quantek Q21 Portable CO₂ Analyzer uses a solid-state non-dispersive infrared (NDIR) sensor. Quantek describes the sensor as using a dual-wavelength infrared measurement principle designed to reduce drift.

NDIR measurement determines CO₂ concentration from the absorption of infrared radiation by carbon dioxide within an optical measurement cell. The Q21 then converts the sensor response into a CO₂ concentration displayed directly on the instrument.

Quantek's currently published Q21 product information and Q20 Series datasheet do not present the CO₂ accuracy specification in exactly the same way. For applications where a specific uncertainty is required, the accuracy specification for the selected Q21 measurement range should therefore be confirmed before instrument selection.

Why is the Q21 relevant for incubator CO₂ spot checks?

Unlike an application inferred only from its measurement range, the use of the Q21 for incubators is explicitly identified by Quantek. The manufacturer describes the Q21 as a portable analyzer for CO₂ measurements in incubators and bio-enclosures.

Several instrument characteristics are directly relevant to this type of measurement:

• 0–20% CO₂ measurement range, covering the concentrations encountered in many CO₂-controlled laboratory environments
• 0.01% CO₂ sensitivity on the 0–20% range
• Integrated sample pump for drawing gas from a sampling point
• Portable design for spot checks across different locations or incubators
• Approximately 20-second final reading
• On-board data collection and CSV export
• PTFE sampling filter option for protection against moisture and particulates
• Battery operation for portable laboratory use

These characteristics make the Q21 particularly relevant when the requirement is for periodic external CO₂ measurements rather than permanent chamber monitoring.

What should be considered before measuring incubator CO₂?

Before selecting an external analyzer or defining a measurement procedure, several practical questions should be reviewed:

• What CO₂ concentration range needs to be measured?
• What measurement uncertainty is acceptable for the application?
• Does the incubator provide an appropriate external sampling port?
• Can condensation be prevented from entering the sampling line?
• Is the requirement for an occasional spot check or a more frequent measurement routine?
• Does the laboratory need to record and export measurement results?

Considering these points helps ensure that the analyzer, sampling configuration and measurement procedure correspond to the actual incubator application.

Discuss your incubator CO₂ measurement application with ES Canada

The Quantek Q21 Portable CO₂ Analyzer provides an external method for spot measurement of carbon dioxide in incubators and bio-enclosures. For incubator applications, particular attention should be given to the required measurement range, sampling point and management of high-humidity gas samples.

ES Canada can help review your CO₂ measurement range, sampling configuration and measurement requirements to determine whether the Q21 corresponds to your application.

Contact ES Canada