The Breathalyzer ™ Presented By Lauren Mercier. What Happens to Alcohol in My Body After I Have a...
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Transcript of The Breathalyzer ™ Presented By Lauren Mercier. What Happens to Alcohol in My Body After I Have a...
The Breathalyzer™
Presented By Lauren Mercier
What Happens to Alcohol in My Body After I Have a
Drink? Ethanol is immediately absorbed into
thecapillaries of body tissues and organs
When it enters the blood stream, ethanol is not metabolized and remains a separate component in blood flow
As blood flows across alveoli in the lungs, carbon dioxide molecules are exchanged for oxygen molecules
Ethanol evaporates from the blood into the breath since it is volatile, and is released with CO2 upon exhaling
+ CH3CH2OH
Relating Breath Alcohol to Blood Alcohol
The ratio of breath alcohol to blood alcohol is 2100 : 1, so 2100 mL of alveolar air contains the same amount of alcohol as 1 mL of blood
Blood alcohol content (BAC) can be calculated from the content of alcohol in the breath% BAC = g Ethanol x 2100mL Breath x 100% 52.5 mL Breath 1mL Blood
BAC of 0.08 means there are 0.08 g alcohol per 100 mL of blood
The Breathalyzer™
Measures concentration of alcohol in breath sample and determines BAC
Invented by Dr. Robert F. Borkenstein of Indiana State Police Department and has been on the market since 1954
Used to prosecute drunk drivers with BAC’s above legal limit of 0.08
Involves a “wet” chemistry reaction, modern models employ Infrared spectroscopy and fuel cells
Breathalyzer™ Apparatus Mouthpiece and thermostat set at 50°C +/- 3°C Sample chamber, contains piston that traps 56.5mL
breath and delivers 52.5mL breath to reaction mixture
Two sealed glass vials containing reaction mixture
H2SO4 (50 % by volume)
K2Cr2O7 (0.025 %)
AgNO3 (0.025 %) Light bulb between glass vials and photocells on
either side Meter connected to electrical output Alcohol scale
Collecting the Sample… The suspect blows into the mouthpiece
and their breath travels to a sample chamber
One glass vial neck is broken (test vial) and a glass tube, called a “bubbler”, is inserted
The operator turns a control knob to release the piston and force the sample through the bubbler into the test vial
Chemical Reaction
2 K2Cr2O7 + 3 CH3CH2OH + 8 H2SO4
2 Cr2 (SO4)3 + 2 K2SO4 + 3 CH3COOH + 11 H2O
AgNO3
If the Suspect Is Drunk… Ethanol in the breath reduces dichromate
ion to chromium ion The test vial lightens from pale yellow to a
bleached yellow colour, like weak lemonade More light passes through the lightened test
vial and hits a photocell causing electrical needle on meter to move
The operator turns a knob to balance needle and light moves away from test vial
When the needle is centered the operator reads alcohol meter to determine BAC
The Intoxylizer™
Uses Infrared spectroscopy to detect ethanol (C-O, O-H, C-H, C-C bonds)
IR energy passes through sample chamber containing breath sample and then through narrowband IR filter
Filtered energy focused on photocell detector which converts it to electrical pulses
Microprocessor interprets pulses and calculates BAC
Quartz Lamp
Breath Sample In Breath Sample Out
Sample Chamber
Lenses
Filter Wheel
Photocell
Microprocessor
Examples of Alcohol Detecting Devices
Intoxylizer® 8000 uses IR spectroscopy
Intoxylizer® 400 uses electrochemical fuel cells
Fuel Cell Detectors Apparatus consists of two platinum electrodes
with acidic electrolyte material between them Ethanol in breath oxidized at surface of anode
to give acetic acid, protons, and electrons Atmospheric oxygen reduced at cathode to
give two oxygen atoms Protons and electrons from anode travel to
the cathode and combine with oxygen to form water
Movement of electrons produces a current that is proportional to the amount of alcohol in the breath sample
Microprocessor measures the current and calculates BAC
In Conclusion… There are several methods available for
forensic alcohol testing Now there are hand held breath alcohol
testers to take on site or to parties to decrease the number of people who drink and drive
Results provide evidence in DWI trials Results can be inaccurate because of
temperature changes and varying blood to breath ratios
Tests are non-invasive and fairly accurate but require a trained operator
References http://science.howstuffworks.com/framed.htm?parent=breathalyzer.
htm&url=http://nydwi.com/dwiqanda/ http://www.occid.org/legislation/bac-priority.pdf http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookRESPSYS
.html#The%20Human%20Respiratory%20System http://science.howstuffworks.com/framed.htm?
parent=breathalyzer.htm&url=http://nydwi.com/dwiqanda/ http://www.craigmedical.com/Breathalyzer_FAQ.htm http://www.alcoholtest.com/ecfuel.htm http://www.alcoholtest.com/ir.htm http://www.druglibrary.org/schaffer/Misc/driving/s5p4.htm http://www.lion-breath.com/serv01.htm Labianca, Dominick A. “The Chemical Basis of the Breathalyzer: A
Critical Analysis”, Journal of Chemical Education. (1990). 67(3). 259-261.