Technical FAQ
Electrochemical Sensors, also known as fuel cells, have many advantages that make them attractive for use as the primary sensor in evidential breath testing devices. The fuel cell’s inherent specificity for alcohol makes it a superior means of measuring alcohol in a breath sample. No substance remaining in a subject’s breath after a short deprivation period will create a reaction in the cell – except alcohol. Fuel cells have become recognized in the scientific and forensic community as accurate and reliable.
Integrating the fuel cell output is a patented method for interpreting the information generated from the sensor. This technique was essential in solving several of the technical issues that caused many to believe that fuel cell instruments would always remain screening instruments. Integration effectively eliminates the “slumping” effect seen in sensing devices that used “peak” analysis techniques. As well, integration has allowed for longer term calibrations.
Yes, fuel cells are electrochemical sensors. The electrochemical fuel cell sensor generates an electronic response that is proportional to the Breath Alcohol Concentration in the provided breath sample. The fuel cell sensor is specific for alcohol. It does not respond to acetone or other substances that can be found in human breath.
No, each manufacturer has its own technique to build the sensor and case. Intoximeters uses a patented case design that allows for not only faster cleanup after use, but also the highest degree of accuracy and stability in the industry.
Yes, the Intox EC/IR as well as the Alco-Sensor IV / RBT IV are widely used for evidential testing. Most recently, the Alco-Sensor VXL @Point of Arrest System is being introduced as a roadside evidential system.
Electrochemical sensors have limited inherent response to potential interferants. There have been many studies done indicating that naturally occuring compounds in human breath do not significantly affect fuel cells.
Current fuel cell life expectancy averages between 7 and 9 years. However, operating conditions and environmental factors can affect the life of the fuel cell.
- Avoid exposing the cell to cigarette smoke, both in breath samples and in the ambient environment.
- Avoid storing the device in extreme temperatures.
- Use the device regularly. Leaving the instrument in storage can cause the cell to dry out, which reduces its useful life.
- Never submerge the instrument in any liquid or introduce liquid of any kind into the breath inlet or fuel cell port.
- Avoid repeated use of breath sprays and mouthwashes to simulate positive results when training or demonstrating the device.
Average fuel cell life is 7 to 9 years, depending on use. As a fuel cell ages, it begins to take longer for the sensor to produce the information needed to calculate the result. The slowness of the cell does not mean it cannot produce consistent and accurate results. However, if the speed to result is an issue for the user, the slow response of an older cell could be a limiting factor that determines when to change the cell.
