Warm Up (Critical Thinking) Connect the dots with 4 lines without picking up your pencil.

Warm Up (Critical Thinking)Connect the dots with 4 lines

without picking up your pencil.

Copyright © 2013 Crosscutting Concepts, LLC. All Rights Reserved.www.CrosscuttingConcepts.com

Objective

• SWBAT understand the process to identify drugs and compare/contrast those methods.


Agenda

1. Chromotography

2. Paper Chromotography Lab

3. Pablo Escobar Documentary

4. Exit Slip


Confirmatory Testing

• The analysis of controlled substances is a forensic science discipline with a strong scientific foundation.

• The analytical methods used have been adopted from classical analytical chemistry, and there is broad agreement nationwide about best practices.

• In 1997, the Scientific Working Group for the Analysis of Seized Drugs (SWGDRUG) was established.

• The mission of SWGDRUG is to recommend minimum standards for the forensic examination of seized drugs and to seek international acceptance for those standards. http://www.swgdrug.org/

http://www.swgdrug.org/


Confirmatory Analysis

• It is important to use more than one method to test drug samples.

• Some analytical methods are more accurate than others.


Qualitative vs Quantitative Tests

• Qualitative tests can define what type of drug is present but lacks the ability to determine how much drug is present.

• Various criminal charges depend on knowing how much of a drug is present. This requires a quantitative test.

• In a quantitative test, the sample is weighed and then the test is used to estimate what mass of the sample is the drug. The mass of the drug is divided by the total mass to give the percentage of drug in the sample.


Analysis of Controlled Substances

• For a test method to be considered of value in establishing the forensic identification of a drug, the results shall be considered “positive.”

• “Negative” test results provide useful information for ruling out the presence of a particular drug or drug class, these results have no value toward establishing the forensic identification of a drug.


Screening Vs. Confirmation

• Screening Tests (Preliminary)– Color Tests

• Confirmation Tests– Microcrystalline Tests– Chromatography


Microcrystalline Tests

• More specific than color tests• Analysts now have hundreds of crystal tests to

characterize most commonly abused drugs• Scientists do not fully understand why most

color and crystal tests produce the results that they do.– From a forensic chemists point of view, it doesn’t

matter…when the tests are properly chosen and used in proper combination, results are characteristic for one and only one drug.


Microcrystalline Tests1. A drop of a suspected chemical solution

is added to a small quantity of the chemical on a slide

2. The solution will begin to re-crystallize

3. Under a microscope, the size and shape of the crystals are characteristic of the specific chemical

– These tests are rapid, cheap, and often do not require the isolation of a chemical from its diluents


Examples of everyday crystals

Copper Sulfate (40x) Copper Sulfate (100x)


Cocaine

Applications in Forensic Science

T. Trimpe 2006 http://sciencespot.net/

What is chromatography?

From Wikipedia ...

Chromatography (from Greek word for chromos for colour) is the collective term for a family of laboratory techniques for the separation of mixtures. It involves passing a mixture which contains the analyte through a stationary phase, which separates it from other molecules in the mixture and allows it to be isolated.

Which means ...

Chromatography is the physical separation of a mixture into its individual components.

We can use chromatography to separate the components of inks and dyes, such as those found in pens, markers, clothing, and even candy shells. Chromatography can also be used to separate the colored pigments in plants or used to determine the chemical composition of many substances.

http://members.shaw.ca/vict/chemistry_test3.htm

Gas ChromatographyUsed to determine the chemical composition of unknown substances, such as the different compounds in gasoline shown by each separate peak in the graph below.

Paper ChromatographyCan be used to separate the components of inks, dyes, plant compounds (chlorophyll), make-up, and many other substances

Liquid ChromatographyUsed to identify unknown plant pigments & other compounds.

Thin-Layer ChromatographyUses thin plastic or glass trays to identify the composition of pigments, chemicals, and other unknown substances.

Examples of Chromatography

Comparison of Chromatography

Go to the website link: http://www.ausetute.com.au/chromato.html

1. Read through the information

2. Make a chart to compare the four types of chromatography

http://www.ausetute.com.au/chromato.html

Chromatography

http://sod-a.rsc-cdn.org/www.rsc.org/learn-chemistry/Collections/spectroscopy/Content/FileRepository/chromatography/GC-simple%20animation.swf





Paper Chromatography

https://www.youtube.com/embed/h809MVrvJ7k?wmode=transparent&rel=0



HPLC

http://www.rsc.org/learn-chemistry/collections/spectroscopy/introduction#GasChromatography



Mixtures & Compounds

Mixture – Two or more substances that are mixed together, but not chemically combined.

Examples of mixtures ...Air – mixture of gasesBowl of cereal – mixture of cereal and milkSoda pop – mixture of soda syrup, water, and CO2 gasFog –water suspended in airKool-Aid – mixture of water, sugar, and flavor crystals

Examples of compounds ...Salt –Sodium and chlorine combined chemicallyWater –Hydrogen and oxygen combined chemically Carbon Dioxide – Carbon and oxygen combined chemically

Compounds – Two or more elements that are chemically combined.

Solutions

Solutions are mixtures in which one substance is dissolved in another.

Solutions have two parts: solute and solventThe solute is the substance that is dissolved.The solvent is the substance that does the dissolving

Identify the solute and solvent in each solution ...

Solution Solute Solvent

Kool-Aid

Ocean water

Solubility - A measure of how much of a given substance will dissolve in a liquid.

A substance that does not dissolve in water is called insoluble. A substance that does dissolve in water is called soluble.

Paper Chromatography Lab• Obtain the supplies you’ll need.

– 1 beaker filled with water– 2 half pieces of filter paper– 2 black markers for testing– 2 small pieces of masking tape– Pencil (to attach to the top of the filter paper)

• Write the marker number on a piece of masking tape and place it at the top of the strip.

• Choose one of the testing markers and draw a thick line with one of the black markers near the bottom of the filter paper - about ¼ inch from the bottom.

• Pour a small amount of water into the beaker and then hang the paper strip in the cup. Make sure the ink line does not touch the water – only the bottom of the filter paper.

• Allow the water to move up the paper for 5 minutes and then remove the strip from the water. Hang it on the side of the table to dry.

• Follow these directions to test the other markers.

Pencil

Filter Paper

InkMark

Tape – Label with marker

Questions:

What colors did your group observe in each of the black ink samples?

Do the colors occur in the same order on all the samples? Explain.

Do you think linking a brand of marker or pen to the crime is enough evidence to convict a suspect? Why or why not?

Complete the chart on your worksheet and then answer the questions.


Pablo Escobar Documentary9. What caused the Columbian government to allow the CIA and the

United States to help find Escobar?

10. How did the U.S. eavesdrop?

11. What did Escobar do when the search block was formed and was he successful?

12. What did Escobar do when he was desperate in the war against the Columbian government?

13. What was the deal that Pablo made with the Columbia government?

14. What changes were made to the constitution?

15. What was different about Escobar’s time in prison?

16. What was the turning point for the President and what did they do?

17. What was different with the “Search Block” the second time around?


Homework

• Chapter 5 Review, #6-10, 14-15, 17-20, 22-34


Exit SlipOctober 29, 2014

• Go to m.socrative.com and enter code 417101• Question: What is the difference between

preliminary and confirmation tests?

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