D.4.3

=**__D.4.3 Describe and explain the techniques used for the detection of ethanol in the breath, the blood and urine.__**=


 * Alcohol Breathing Test:**

Breathalyser: Potassium Dichromate (VI)


In the reaction above,
 * The **Sulfuric Acid** is used to create a **liquid solution** containing the **ethyl alcohol from the breath**, which was originally in gaseous state
 * The **Potassium Dichromate** (reddish-orange) is used to **react with the Ethyl Alcohol**, which results in the production of **Chromium Sulfate (green),** Potassium Sulfate, Acetic Acid, and Water
 * The **Silver Nitrate is used as a catalyst**
 * The **shade of green** of the Chromium Sulfate **indicates the amount of Ethyl Alcohol** in the reaction
 * In order to determine the amount of Ethyl Alcohol in the reaction, the solution resulting from this reaction is compared to the original non-reacted solution in a photocell system
 * The photocell system sends a current through the solutions, which moves a needle on a display, and the concentration of Ethyl Alcohol is shown through how much the operator has to turn a dial to move the needle back to its resting point
 * A breathalyzer test **CANNOT** determine the blood alcohol concentration of an individual, only a blood alcohol test can. The breath alcohol concentration is generally used in order to **estimate** the blood alcohol concentration of an individual

Intoximeter: Absorption of Infrared Radiation
The use of infrared to detect ethanol in a person's breath is based on the fact that __certain infrared wavelengths can be absorbed by ethyl alcohol (ethanol) molecules__




 * Part A** The Infrared Radiation is generated, usually from a __quartz lamp__.
 * Part B** The person __breathes into__ this part
 * Part C** Where the __breath comes out__
 * Part D** The __sample chamber__, where the breath is stored.
 * Parts E** The __lenses that focus__ the IR beam from the lamp.
 * Part F** The __filter wheel__, it filters out everything but specific wavelengths of the bonds in ethanol.
 * Part G** A __photocell__, which converts those wavelengths into an electric pulse.
 * Part H** The __microprocessor__, which interprets the electric pulse and calculates the Blood Alcohol Concentration based on the change in bond lengths in the ethanol.

Intoximeter: Fuel-Cell
By oxidizing ethanol, you get **acetic acid**, and **two hydrogen atoms** (two protons, and two electrons) The devices using the fuel cell technology to detect alcohol have **two platinum electrodes**, and a **electrolyte material** in between. The **protons then move across the electrolyte**, while the **electrons move through wires connected to the platinum plates**. On the other side, **the protons and electrons bond with oxygen to form water**. **The current across the wire is measured**, and sent to a microprocessor, which calculates the BAC.

. ([])


 * Alcohol Urine Test:**

Detecting Alcohol Level in Urine
(http://www.buzzle.com/articles/alcohol-urine-test.html) - When alcohol is consumed, it travels through your body and through the small intestine. - Depending on one's metabolic rate the time it reaches the urine after comsumption varies. - Alcohol urine testing is **RELIABLE** because, this test can show presence of alcohol in body for 2 to 3 hours more than the Blood Alcohol Test can. - It cannot show the exact degree of alcohol consumption. - It will only show results up to 5 days after alcohol consumption. - Many factors influence the level of alcohol in ones blood; a persons metabolism, and dehydration level. - Collected through means of a plastic container. - Usually one sample is taken, but sometimes two samples, a primary and secondary sample, are taken for consistency.

-The client is asked for urine specimen, and then the alcohol is detected by its metabolite Ethyl glucuronide (EtG), (so the presence of EtG shows that there was alcohol consumption). -Methods
 * Method (Chromatography)**

The cut off is 100 nanograms per millimeter of EtG, which means definitive alcohol consumption. ( http://www.expertdrugtesting.com/content/view/32/1/)
 * immunoassay (EIA or ELISA)
 * gas chromatography/mass spectrometry (GC/MS
 * liquid chromatography/mass spectrometry (LC/MS)
 * liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS)


 * Alcohol Blood Test:**
 * ** Blood Alcohol Concentration (BAC) is measured in percentage by mass or mass per volume. (E.g. 0.20% BAC means 1 gram of alcohol per 500 grams of blood) **
 * An alcohol blood test measures the amount of alcohol (ethanol) in a person's body.
 * Alcohol is absorbed into the bloodstream very quickly and can therefore be detected within minutes of drinking.
 * A blood alcohol test is used to find out if a person is legally drunk or wasted.
 * ** It is done by a health professional drawing blood which is then analyzed in a laboratory. **