Two techniques used by the instrument?

Two techniques used by the instrument?

• A. Gas chromatography and infrared absorption
• B. Mass spectrometry and chromatography
• C. Electrochemical sensor alone
• D. Electrochemical fuel cell and infrared energy absorption

Answer: (D)

The test hinges on recognizing that this instrument relies on two different detection principles to measure a breath alcohol level. One is an electrochemical fuel cell sensor, which responds to ethanol in the breath by producing a current directly proportional to the amount of alcohol present. That current provides the quantitative reading of the measured blood-alcohol concentration. The other principle is infrared energy absorption, which analyzes how the breath absorbs infrared light at wavelengths specific to ethanol. This serves as a confirmation method, helping to verify that the detected signal is indeed due to ethanol and not another substance, and can help identify potential interferences. Using both methods together improves accuracy and reliability: the fuel cell gives a straightforward, rapid measurement, while infrared absorption provides additional verification. The other options either rely on a single method or invoke techniques (like gas chromatography or mass spectrometry) that aren’t how a typical handheld breathalyzer operates.

The test hinges on recognizing that this instrument relies on two different detection principles to measure a breath alcohol level. One is an electrochemical fuel cell sensor, which responds to ethanol in the breath by producing a current directly proportional to the amount of alcohol present. That current provides the quantitative reading of the measured blood-alcohol concentration.

The other principle is infrared energy absorption, which analyzes how the breath absorbs infrared light at wavelengths specific to ethanol. This serves as a confirmation method, helping to verify that the detected signal is indeed due to ethanol and not another substance, and can help identify potential interferences.

Using both methods together improves accuracy and reliability: the fuel cell gives a straightforward, rapid measurement, while infrared absorption provides additional verification. The other options either rely on a single method or invoke techniques (like gas chromatography or mass spectrometry) that aren’t how a typical handheld breathalyzer operates.