Fuel-Cell Breath Analyser
Definition
Electrochemical sensor: ethanol oxidises at a platinum electrode generating a current proportional to BrAC. Specific for ethanol, used in Drager Alcotest and Lion Alcolmeter handheld units.
- Sensor type
- Electrochemical, platinum electrode
- Target
- Ethanol only, oxidised at the electrode
- Output
- Current proportional to breath alcohol concentration
- Example devices
- Drager Alcotest, Lion Alcolmeter
Common questions
How is this different from an infrared breath analyser?+
Infrared devices measure absorption across a range of molecules and can respond to other volatile compounds unless filtered, while a fuel-cell sensor reacts almost exclusively to ethanol through its electrochemical oxidation reaction, giving it high specificity in a compact handheld unit.
Why do fuel-cell units need periodic recalibration?+
The platinum electrode's response can drift with age, temperature, and repeated use, so evidentiary breath-testing instruments require documented calibration checks against a known ethanol standard to keep results defensible in court.
Related terms
- ADH Assay
- Alcohol dehydrogenase enzymatic assay. Ethanol plus NAD+ gives acetaldehyde plus NADH; NADH absorbance at 340 nm is proportional to ethanol concentration. Fast...
- BAC
- Blood Alcohol Concentration. Mass of ethanol per unit volume of whole blood. Indian legal cut-off is 30 mg per 100 mL (0.03...
- Headspace GC-FID
- Gas chromatography with flame-ionisation detection run on the vapour above a sealed sample. The standard forensic method for methanol and ethanol in...
- IR Breath Analyser
- Infrared absorption at about 3.4 micrometres (C-H stretch) or 9.5 micrometres (C-O stretch). Specific and quantitative; used in Intoxilyzer 8000 and evidential...
- Putrefactive Ethanol
- Ethanol produced post-mortem by microbial fermentation of glucose, lactate and amino acids. Can give false-positive BAC; vitreous humor is the matrix of...
- Wet-Bath Simulator
- Calibration accessory holding a 0.10 g per L aqueous ethanol solution at 34 degrees Celsius. The vapour above gives a known reference...
- Widmark Formula
- A = r × W × C, where A is total alcohol in body (g), W is body weight (kg), C is...