Breathalyzer or alcohol detector www.whatengineers.com We hear and read about drivers involved in an accident who are later charged with drunken driving, and usually a news report on the accident will say what the driver's blood alcohol level was and what the legal limit for blood alcohol is. A driver might be found to have a level of 0.15, for example, and the legal limit is 0.08. But what do those figures mean? And how do police officers find out if a driver they suspect has been drinking is actually legally drunk? You have probably heard about the Breathalyzer, but may wonder exactly how a person's breath can show how much that person has had to drink. It is important for pu­blic safety that drunken drivers be taken off the roads. Of the 42,000 traffic deaths in the United States in 1999, about 38 percent were related to alcohol. Drivers who can pass roadside sobriety tests -- they can touch their noses or walk a straight line -- still might be breaking the legal limit for blood alcohol and be a hazard on the road. So police officers use some of the latest technology to detect alcohol levels in suspected drunken drivers and remove them from the streets.

1. Talha Anwar
CMS: 14432
Presented to: Dr. Shafique

2. Introduction
• Breathalyzers estimate Blood Alcohol Content (BAC) from the
concentration of ethanol in the breath.
• Advantages:
• Easy To use
• Portable
• Disadvantages
• high price
• a short lifetime and
• the need for continuous recalibration.

3. Organic electrochemical transistor (OECT)
• The organic electrochemical transistor (OECT) is a transistor in which
the drain current is controlled by the injection of ions from
an electrolyte into a semiconductor channel
• The injection of ions in the channel is controlled through the
application of a voltage to the gate electrode.
• OECTs are being explored for applications
in biosensors, bioelectronics and large-area, low-cost electronics.

4. • breathalyzer uses an organic electrochemical transistor (OECT)
modified with alcohol dehydrogenase (ADH) as the sensor.
• ADH and its cofactor nicotinamide adenine dinucleotide (NAD+) are
immobilized onto the OECT with an electrolyte gel.
• When the OECT-breathalyzer is exposed to ethanol vapor, the
enzymatic reaction of ADH and ethanol transforms NAD+ into NADH,
which causes a decrease in the OECT source drain current.
• In this fashion, the OECT-breathalyzer easily detects ethanol in the
breath equivalent to BAC from 0.01% to 0.2%.

5. Causalities due to alcohol
• Nearly 88,000 people (approximately 62,000 men and 26,000
women) die from alcohol-related causes annually, making alcohol the
fourth leading preventable cause of death in the United States.
• In 2013, 10,076 people lost their lives in alcohol-related-driving
accidents in the United States alone
• In 2014, alcohol-impaired driving fatalities accounted for 9,967 deaths
(31 percent of overall driving fatalities).
• Driving under the influence is illegal and the maximum allowed blood
alcohol concentration (BAC) is 0.05–0.08%, in most countries

6. Generation of breathalyzer
• The first generation of breathalyzers uses a liquid dye sensitive to
ethanol exposure, potassium dichromate, and a photodetector.
• Reliability of these detectors is a challenge and potassium dichromate
is environmentally toxic
• A new generation of breathalyzers uses the ethanol in the breath to
power a fuel cell whose output is proportional to the ethanol
concentration

7. • Available in phone, but it require constant recalibration.
• the most reliable BAC tests and the only one that is admissible in
court is the blood test, which is difficult to administer on site or for
preventative purposes.
• Organic electrochemical transistors (OECTs) are excellent candidates
for disposable biosensors because they are inexpensive, they can be
made on flexible substrates, and they can be printed on paper

8. Reactions
• The alcohol dehydrogenase (ADH) enzyme and the OECT are the key
components of the sensor.
• The OECT comprises of source (S), drain (D), and gate (G) electrodes.
First the reaction yields the reduced form of nicotinamide adenine dinucleotide (NADH),
which itself oxidizes according

9. • Since the concentration of NADH is directly related to the
concentration of ethanol in the breath, this mechanism leads to
quantitative ethanol detection.
• Higher ethanol concentration corresponds to higher ΔId as observed
with NADH

10. • Seven volunteers participate in the breath alcohol test for
BAC detection. One volunteer serves as the control, while
other volunteers consume different amounts (120 ml and
240 ml) of red wine (Les 3 filles, 2014, Merlot, 13% alcohol
content).
• Thirty minutes after wine consumption, the volunteers are
subject to a breath test with a commercial breathalyzer for
calibration and then are subject to the same test with the
OECT-breathalyzer. The results from the two tests are
compared for accuracy and they are almost accurate.
• Further more time variation has same effect on both sensor

11. Result