Control & Repeatability for off-line breath analysis.
Keeping breath samples as intact as possible is important to reduce the chances of accidentally introducing contaminants and confounding variables that could be potentially misinterpreted as bio-markers. On-line breath analysis provides the most direct method of collecting the data, but not all patients can walk to the lab and consciously exhale into SUPER SESI.
For these situations, the OFF-LINE REPLICATOR is the solution:
- First, breath is collected off-line through an Exhalion breath regulator in a gas tight bag made of low-out gassing inert material
- Then, the content of the bag is passed to the SUPER SESI for analysis
but it is not so easy...
Normally, the bag is at room temperature, and low volatility species tend to condensate in the inner walls of the bag.
If the bag is emptied at room temperature, condensation can drastically affect the measurements, producing very random signals, with poor sensitivity for the low volatility species:
- Low volatility species are trapped onto the walls and they are not passed to SUPER SESI
- Due to the low thermal inertia of the thin film making the bag, some species can be inadvertently released when the operator touches the bag
- water can be condensed in the inner walls of the bag, and the actual humidity level of the gas depends on too many factors
what is the off-line replicator?
OFF-LINE REPLICATOR introduces the sample in SUPER SESI as if the patient had directly exhaled in the SUPER SESI.
Replicating the conditions of analysis is crucial to ensure that breath data collected off-line is compatible with data collected on-line.
OFF-LINE REPLICATOR provides a gas tight chamber to extract the gas collected in the bags.
- The bag is heated until it reaches a uniform temperature
- Then, the sample is introduced at a controlled flow rate in SUPER SESI replicating a predefined number of exhalations
Reliable and repeatable sample introduction
Temperature control: A uniform and constant temperature control ensures that low volatility species are released in the gas phase under the same conditions in all tests.
- Low volatility species are released back in the gas phase
- condensed water is re-evaporated, reproducing the original humidity level of the exhaled air
Flow control: A controlled flow of gas is used to pressurize the chamber and to compress the bag.
This provides an optimum control of the flow and an optimum transmission from the bag to the ionizer.
- The gas in the bag does not encounter any extra valve or moving part that could introduce any contaminant
- The flow path is carefully heated to avoid cool spots in which some low volatility species could be lost
- The bag is emptied in pulses of predefined duration, replicating a set of exhalations as if a person was exhaling in the SUPER SESI
Timing: The bag is inserted in the OFF-LINE REPLICATOR manually. Once inserted, a predefined routine is started. This routine defines the heating time, the output flow, the number of replicated exhalations, and their duration.
Ergonomics: a transparent gas tight cover, and a simple frontal panel that incorporates the components required to control the temperature and the flow, and to initiate the analysis of each bag.
Minimizing cross contamination: By confining the bags and using high purity gas, OFF-LINE REPLICATOR minimizes the chances of cross-contamination during manipulation.
OFF-LINE REPLICATOR IS MEANT TO ENABLE COLLECTION OF BREATH SAMPLES WHEN ONLINE ANALYSIS IS NOT POSSIBLE.
Bread metabolites stored for long periods of time tend to degrade.
For this reason, bags should not be used as a method to store breath samples for more than 24h. Once a breath sample is collected in a bag, we strongly recommend to analyze its content as soon as possible.