Infrared Spectral Interpretation of Trace Evidence & Controlled Substances

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Instructor: Dr. Brian C. Smith


Why Take This Course?

  • Discover a proven 12-step program for interpreting spectra successfully
  • Learn to perform spectral comparisons (identities) properly
  • Master the spectra of forensically important molecules
  • See how subtraction and library searching make interpretation easier
  • Understand what all the peaks in your spectra mean
  • Hone your interpretation skills by working problems in IR Spectral Interpretation Workshops


Course Length: Three 8 hour days taught online

I. The Fundamentals of Infrared Interpretation

            A. The Meaning of Peak Positions, Heights, and Widths

            B. How Molecules Absorb Infrared Light

            C. Different Types of Infrared Features

            C. A Systematic Approach to Spectral Interpretation

                        1. Dealing with Mixtures

                        2. Performing Identities Properly

                        3. A Systematic 10-Step Approach to Infrared Interpretation


II. Saturated Hydrocarbons

            A. Straight Chain Alkanes

            B. Estimating Hydrocarbon Chain Length

            C. Branched Alkanes

            D. Cyclic Alkanes: Cyclohexyl and Cyclopentyl Rings


III. Unsaturated Hydrocarbons

            A. Alkenes:

                        1. Substitution Patterns

                        2. Distinguishing Cis/Trans Isomers

                        3. Natural & Synthetic Rubbers

            B. Alkynes


IV. Aromatic Hydrocarbons

            A. Benzene & Mono-Substituted Benzene Rings

            B. Distinguishing Ortho, Meta, and Para Isomers

            C. Highly Substituted Benzene Rings

            D. Heterocyclic and Polycyclic Aromatic Hydrocarbons


V. Molecules with C-O Bonds

            A. Alcohols & Phenols

                        1. Differentiating Primary, Secondary, and Tertiary Alcohols

                        2. Phenols

                        3. Distinguishing Alcohols from Water

            B. Ethers

                        1. Saturated & Branched Ethers

                        2. Aromatic Ethers

                        3. The Methoxy Group

            C. Sugars and Carbohydrates

                        1. Glucose and Other Sugars

                        2. Oligosaccharides

                        3. Cellulose


VI. The Carbonyl (C=O) Functional Group

            A. Ketones

            B. Aldehydes

            C. Carboxylic Acids

            D. Acid Anhydrides

            E. Carboxylates (Soaps)

            F. Esters: The Rule of 3

            G. Organic Carbonates


VII. Organic Nitrogen Compounds

            A. Amides

            B. Imides

            C. Polyurethanes

            D. Amines

                        1. Distinguishing the Three Types of Amines

                        2. Methyl Groups Bonded to Nitrogen

                        3. Amine Salts

            E. Nitriles

            F. The Nitro Group


VIII. Organic Sulfur, Silicon, and Halogen Compounds

            A. Organic Sulfur Compounds

            B. Siloxanes (Silicones)

            C. Halogen/Carbon Bonds


IX. Inorganics

            A. Sulfates

            B. Silica

            C. Nitrates

            D. Inorganic Carbonates

            E. Phosphates


X. The Infrared Spectra of Polymers

            A. Low and High Density Polyethylene

            B. Polypropylene

            C. Polystyrene

            D. Polyethylene Terephthalate (PET)

            E. Acrylates

            F. Polyurethanes

            G. Polycarbonates: Lexan

            H. Polyimides: Kapton

            I. Teflon 


XI. Handling Mixture Spectra Properly

            A. The Laws of Spectral Processing

            B. Spectral Subtraction

            C. Library Searching

            D. Properly Interpreting Search Results

            E. Subtract & Search Again for Mixture Analysis


XII. The Infrared Spectra of Controlled Substances

            A. Distinguishing Cocaine from Cocaine Base

            B. Stimulants (Phenylalkylamines)

                        1. Methamphetamine

                        2.  MDA, MDMA, and MDEA

            3. Ketamine & Mescaline

C. Depressants (Benzodiazepines)

D. Analgesics (Morphine Derivatives)

                        1. Morphine

                        2. Heroin

                        3. Hydromorphone

                        4. Hydrocodone & Oxycodone

            E. Hallucinogens

                        1. Psilocin and Bufotenine

                        2. LSD

                        3. Angel Dust (PCP)

                        4. Propoxyphene (Darvon)

                        5. Methadone

            F. Tetrahydrocannabinol (THC)

            G. GHB