5 ways SiHuB streamlines calibrating your breath sensors

Published on: 19 Apr 2022, under Science & Research

SiHuB-heroAt Owlstone Medical we’ve been developing breath sampling and analysis technology since 2014, and gas sensors in general for 10 years before that, as part of Owlstone Inc. We learned quite early on that many gas and breath sensor calibration systems can be inflexible, temperamental and expensive.

We developed the SiHuB Sensor Calibration System to cost-effectively create consistent and controllable gas mixtures, including trace volatile organic compounds (VOCs), to calibrate our in-house breath sensors. Read on for five reasons you might want to use SiHuB in your lab too.

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1. Create complex mixtures of accurate standards easily

When you’re calibrating, testing or training your breath sensor, you need to be able to create concentrations of gases that are precise and repeatable. Breath is a famously complex medium, made up of hundreds, possibly thousands of different components, often in concentrations at vastly different orders of magnitude. With SiHuB you can create precise gas concentrations even at part per million to parts per billion levels with every compound traceable to primary standards.


2. Avoid dependance on inflexible and bulky gas cylinders

With other calibration systems creating more complex mixtures can feel like it requires an exponentially more complicated set-up. If you’re reliant on gas cylinders, then you don’t need to introduce many different VOCs before your entire system becomes unwieldy and impractical. SiHuB, with its compact footprint, both streamlines and simplifies this process for you. It’s also safer – as lowering the quantity of target chemicals you require on hand at any time reduces exposure risks.


3. Control humidity levels to simulate human breath

One problem that anyone working with breath sensors needs to deal with early on is breath’s humidity. There’s no getting around the fact that human exhaled breath is extremely wet, and any breath sensor needs to be able to perform under humid conditions. Every SiHuB contains a versatile humidity generator (the OHG-4) that you can produce a range of relative humidity concentrations from 1 to 90% relative humidity (±1%) to allow you to flexibly simulate breath conditions.

SiHuB Schematic
All SiHuB systems include singular OFC-1 and OHG-4 modules that regulate flow through the system and control humidity respectively. However, multiple OVG-4 or V-OVG units can be included to allow various trace gases or VOCs to be included in the final mix.

4. Build a modular system customized to your specific needs

If you want to create a gas mixture that approximates breath to the extent that it can effectively calibrate a breath sensor it’s probably not going to be simple. As human breath is so complex, the ability to combine greater numbers of VOC accurate standards in your gas mixture will enable you to imitate breath’s properties more effectively.

The SiHuB system is modular, allowing you to combine as many VOC standards into a single mixture as you want. Each V-OVG unit allows you to simultaneously add up to six standards to your gas mixture and you can use as many of them as you need. By coupling two V-OVG you could introduce 12 unique standards and so on. Your SiHuB can be as complex or as simple a system as is required by your applications.


5. Create a variety of different standards with just one set of hardware

If the kind of calibration mixtures you require changes in the future you won’t need to buy expensive new hardware. The variety of VOC standards that SiHuB allows you to include in your gas mixtures is limited only by the permeation tubes you can either build or buy. If you cannot source the VOC standard you require from a vendor, then we can supply you with permeation tube manufacturing kits that you can use to create your own standards.


If you’d like to know more about the SiHuB Sensor Calibration System, or if you’re not sure if it’s the right solution for you, our in-house breath researchers can help.

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