Drugs/Toxicology and Arson/Explosives

Drug definition

any chemical that affects the human body or mind when it is consumed in any way

Psychoactive drug definition

affects the brain, most laws against drugs are against psychoactive drugs

Illegal drugs definition

Drugs which a person is not allowed to use

Law says a person cannot own an controlled drug without permission

prescription drug definition

•  pharmaceutical drug that requires a medical prescription to be legally dispensed

over the counter drug definition

 can be obtained without a prescription

United states code (USC) controlled substance act

-Provides a list and rating scale called schedules

-Drugs potency, potential for abuse, likelihood of physical dependence and medical implications are all factored into scheduling 

-Established penalties for offenses

depressant effects

sleepiness, amnesia, impaired judgment, confusion, slurred speech, loss of motor coordination

depressant examples

alcohol, barbiturates, benzodiazepines, GHB, rohypnol

hallucinogens effects

altered perception and mood, mild to severe hallucinations

Hallucinogens examples

LSD, MDMA, PCP, ketamine, mescaline/peyote, mushrooms (psilocybin)

Inhalants effects

Loss of inhibition, intoxication, slurred speech, decreased coordination, euphoria, disorientation

Inhalants examples

ether, nitrous oxide, butane, cyclohexyl, nitrite, amyl nitrite

Marijuana effects

Euphoria or high, altered sensory perception, sleepiness, disrupted coordination/balance

Marijuana examples

marijuana, hashish

Narcotics effects

General sense of well being, drowsiness, inability to concentrate

Narcotics examples

opium, heroin, morphine, methadone, oxycodone

Steroid effects

Mood swings, hostility, impaired judgment, aggression

Steroid examples

human growth steroids, testosterone

Simulants effects

Euphoria or high, exhilaration, wakefulness, agitation, hostility, hallucinations

Simulants examples

amphetamines, methamphetamines, cocaine

Synthetic drugs effects

Agitation, irritability, impaired perception of reality, reduced motor control, inability to think clearly

Synthetic drugs examples

bath salts (cathinones), DXM, salvia

Presumptive testing (drugs ) process

• Typically initially performed by on site law enforcement to indicate if the suspected substance is present or not 

• Test kit will typically produce a positive indicating color if the substance is present 

• Laboratory tests that confirm with certainty the presence of the suspected substance would be performed later 

Presumptive testing process ( Duquenois reagent example)

• Conducted by placing a small sample of suspect material inside the test vial

• Deep blue/purple tint of the liquid inside the vial indicates the test was positive for the cannabinoids present 

• Other THC containing drugs such as marijuana or hash oil will produce a light blue to dark purple reaction 

Confirmatory testing process (drugs)

• Uses instrumental analysis to positively identify the contents of submitted material

• Typically a multi step process to separate the individual compounds 

• Process determines the chemical characteristics of the compounds to be compared to reference materials

• Goal is to make positive identification 

• This is qualitative analysis and determines what substances are present and if one or more of those is illegal 

Drug Analysis Procedures of a Forensic Chemist

-Determine the amount of material

-Presumptive testing

How to determine the amount of material

• Evidence submitted can vary widely in the amount that is collected

• By finding total mass of material this can determine what tests can and can’t be done

Presumptive testing

General screening of the material with the goal to classify the material into a general category

Common types of general screening

Microscope analysis, microcrystalline analysis, ultraviolet spectroscopy

Microscopic analysis

• Visual inspection of the general structure of the material

• Provides a broad classification 

• Typical for larger material sizes

microcrystalline analysis

• Involves dissolving a small amount of material and then allowing crystals to form

• Viewing the crystals with the aid of polarized light can help determine their structure

ultraviolet spectroscopy

• Projecting UV light and measuring the absorbance cna help provide a general classification of the material 

Confirmatory tests

• Use to identify the material and often continue where a presumptive test left off

• Develop a chemical signature 

Gas chromatography

• Common type of chromatography used in analytical chemistry for separating and analyzing compounds that can be vaporized without decomposition 

• Typically used for forensic analysis with the main use for testing bodily fluids

• Uses - testing the purity of a substance, separating the different components of a mixture

• Can be used to identify a compound of residues from explosives 

Liquid chromatography

• Technique used to separate a sample into its individual components based on the interactions of the sample with the mobile and stationary phases 

Capillary electrophoresis

• Analytical technique that separates ions based on their electrophoretic mobility with the use of an applied voltage 

• Electrophoretic mobility is dependent upon the charge of the molecule, the viscosity, and the atoms radius

• Used most predominantly because it gives faster results and provides high resolution separation 

• Useful technique because there is a large range of detection methods available 

Mass spectrometry

• Analytic method that employs ionization and mass analysis of compounds in order to determine the mass formula and structure of the compound being analyzed 

Infared spectroscopy

• Analysis of infrared light interacting with a molecule

• Can be analyzed in three ways by measuring absorption, emission and reflection 

• Main use is in organic and inorganic chemistry

• Used by chemists to determine functional groups in molecules 

Evidence you can use to identify a white powder/substance

solubiulity, water solubility test, HCL solubility, Vinegar solubility, Iodine test, Iron nitrate test, sodium hydroxide test, Phenolphthalein test, ph test, Benedict's reagent, and Biuret's reagent

Solubility

• Chemical property referring to the ability for a given substance, the solute, to dissolve in a solvent

• Measured in terms of the maximum amount of solute dissolved in a solvent at equilibrium 

Water solubility test

• One of the most important and frequently used physical-chemical properties of chemicals

• Tests to see if the substance is polar (dissolves) or nonpolar

• Add about 0.26g sample to a test tube and about 5 mL water and shake tube

HCL solubility

• Follows same concept as water solubility

• Bicarbonates and carbonates react with acid to form carbon dioxide bubbles

• Calcium sulfate and cornstarch aren’t soluble in 10% HCl

• Rest of the powders are soluble

Vinegar solubility

Bicarbonates and carbonates react with acetic acid to form carbon dioxide bubbles

Iodine test

• Starch reacts with iodine to form blue complex

• Put about 0.25g of powder that you suspect to be cornstarch in a test tube

• Add 2 drops of tincture of iodine to the tube, add a few drops of water, mix the contents, note the color

Iron nitrate test

• Transfer about 5 drops of those substances that were water soluble to a well plate

• Place a drop or two of the iron nitrate solution in each well

• Indicate a purple (positive) or light brown/orange (negative) color

sodium hydroxide test

• Magnesium sulfate reacts with sodium hydroxide to form insoluble magnesium hydroxide

• Add about 0.25g of substance to test tube, add 5 mL water, shake the tube

• Add 20 drops of 0.2M NaOH to solution, record observations 

Phenolphthalein test

• Often used as an indicator in acid base titrations and turns colorless in acidic solutions and pink in basic solutions 

ph test

• Universal indicator can be used to test the pH of only water soluble solutions via a color change

• Add the drops of universal indicator directly to test tubes from the water solubility test and record the color

Benedict’s reagent

• Test for simple sugars

• Place 1 mL of sample in test tube

• 2 mL of Benedict's reagent in test tube

• Heat solution in boiling water for 3-5 minutes 

• Observe color change in solution of test tube or precipitate formation

Buirreits reagent

• Test for proteins

• 3 clean test tubes

• Add 1-2 mL of test solution, egg albumin and deionized water in the respective test tube

• Shake well and allow the mixtures to stand for 5 minutes 

• Observe color change

Color (Identifying Chemicals with Spectrophotometry)

• Light is a form of energy and travels in a wave

• Lights wavelengths measured in nanometers determines color

• Objects typically selectively absorb specific wavelengths of light

• Color you see is the wavelength this is being reflected

Spectrophotometer basics (Identifying Chemicals with Spectrophotometry)

• Measures the absorbance of a solution as light of a specified wavelength is passed through it 

• Has a sensor that determines the amount of a specific wavelength of light is being absorbed by a chemical solution

• If light isn’t absorbed meter will read 0

• As the wavelength is benign adjusted absorbance will change

• Results can be graphed to develop and absorption spectrum for the given chemical

Absorption spectrum (Identifying Chemicals with Spectrophotometry)

• Acts like fingerprint for chemical

• Can allow for comparisons of two different substances to determine if they are the same and a known to an unknown chemical 

Preparing chemicals (Identifying Chemicals with Spectrophotometry)

• Must be in liquid form

• Cuvets must be used that match the experiment

• Use distilled or tap water depending on the material being tested

Proper cuvetter handling (Identifying Chemicals with Spectrophotometry)

• Use proper cuvette material for you experiment

• Avoid direct contact when handling with the transmission sides

• Wipe the cuvette with tissue paper before placing the spectrophotometer

Using a spectrophotometer (Identifying Chemicals with Spectrophotometry)

• Follow the directions 

• Basics 

  • Let machine warm up

  • Enter desired wavelength

  • Insert cuvette containing blank solution making sure the clear sides are where the light will pass through it 

  • Zero the solution 

  • Repeat basic process for the samples 

Creating absorption spectrum (Identifying Chemicals with Spectrophotometry)

• With a sample plot the absorption vs wavelength

• Keeping the sample the same the wavelengths will be changes and the resulting absorption reading should be documented

• Goal is to determine the number of peaks a sample may have

Fire triangle

• Fuel + oxygen + heat = fire

• These 3 components are needed for fire to occur

Fuel

• Combustible material

• Material can be in any state of matter

• Most solids and liquids become a vaporize before they will burn

• Ex. clothing, plant material, flammable liquids

Oxygen

• Fire requires at least 16% oxygen in the air

• Atmospheric oxygen levels are 21%

Heat

Will raise the temperature of a fuel source to the point of ignition

Fire investigation

• Workflow should start from minimally damaged areas progressing to ones with greater damage

• Investigators should use typical forms of forensic documentation and collect evidence

• Try to determine point go origin, heat source, possible reasons

Pieces of evidence from a fire investigation

point of origin, char patterns, v patterns, heat shadows, glass clues, chimney effect, color of smoke and flames

Point of origin

• Burn patterns are used

• Area of most damage is commonly where fire started

• Can be used to help determine cause of fire

Char patterns

• Created by very hot fires that burn very quickly that move fast along a path

• Can result in sharp lines between burned and not burned material

• Door char pattern - can help determine which side of the door the fire was on

• Floor char pattern - can help determine if an accelerant was used and its path

V patterns

• Fire burns up in a vertical v-shaped pattern 

• A fire that starts at an outlet against a wall leaves a char pattern that points to the origin 

• Narrow v-shape - typically indicates a hot fire that could have had an accelerant

• Wide v-shape - suggests a slow burning fire

• U-shpae - indicates a pool of origin such as a puddle of gasoline

Heat shadows

• Occur when an object shields another which can help determine origin point

• In a room a desk could shield the wall

Glass clues

• Light bulbs

  • Can aid in fire direction

  • Tend to melt toward heat source

• Windows 

  • Can help determine how a fire burned

  • Presence of a dark soot layer on glass could indicate slow, smoldering fire

  • Clear glass with an abnormal pattern of cracking could imply a very hot fire 

Chimney effect

• When the fire ignites at a point and the superheated gasses rise upward and form a fireball

• This fireball will continue straight up to burn a hole in the ceiling which can help determine the origin of the fire 

  • Would be directly underneath this area

Color of smoke and flames

• Smoke color - indicates type of material burning

• Flame color - indicates fire temperature

Areas likely to contain traces of ignitable liquid

• Depressions or low regions of burn area

• Insulated areas within a pattern

• Porous substrates in contact with the pattern

  • Cex. cloth, paper products, wood

• Seams or cracks

• Lightly burned edges of the pattern 

Fire debris evidence

• Paper and trash will not yield much evidence

• Use of an accelerate will aid in a rapid start

• Was a chemical device used

• Any signs of an electronic device that could purposely delay the initiation of the fire

• Unburned portions of chemical and electronic devices may be left behind

Collecting fire debris

• Along with sample from point of origin, a control sample should be collected

• Carpet fibers (synthetics) may be petroleum based 

• Transfer collected samples in a tightly sealed container

Role of accelerants

• Aid in the initial ignition and potential spread pattern fo the fire

• Sample processing

  • Send to lab in clean vapor tight containers

  • Techniques - heated headspace gas chromatography, adsorption strip, solvent wash 

Accidental fires examples

heating system, electrical equipment, children playing with matches, smoking, cooking 

Non accidental fire clues

• Obvious odors

• Lack of personal objects and valuables

• Check debris for clothing such as button, zippers

• Window and doors are locked and blocked

• More than 1 point of origin

• Inverted v-pattern (sign of accelerant)

• Charred floors - can indicate accelerant use

Suspicous circumstances

• Presences of combustible to aid in the increase rate of combustion

• These are frequently detect by canines trained to detect ignitable liquids by smelling fire debris

• Investigators can also detect the presence of these liquids from pour patterns that remain on the burnt substrate after the fire

Motives for arson

• Crime concealment - to conceal another crime 

• Revenge or spite - to get back at someone for a perceived injustice

• Monetary gain - burn an object to gain profit from the fire 

  • Insurance coverage, putting a competitor out of business

• Malicious vandalism - fire set just to destroy, largest percentage arson fires, typically set by juveniles

• Mentally disturbed - irresistible impulse to set fires

Pour pattern

Often characterized by intermixed light, medium, and heavy burning in a puddle shape that corresponds to the shape of the original pool of liquid

Indicators of flammable liquid use

• Unnatural flame movement (downward or too fast)

• Gapping of wood or floor seams (caused by pooling of liquid)

• No identifiable point of origin of the fire

• Flooring underneath appliances and furniture is burned

• Inverted cone shaped burn patterns on vertical surfaces

V burn pattern

• Classic v shape is the normal burn pattern 

• Inverted v or cone indicates an accident or use of an accelerant

Burn pattern with accelerants

• Alligatoring (scales0 - possible accelerant use

• Spalling (breaking away layers) - possible accelerant use

• Streamers (trail) - accelerant used to spread

• Pool or plant (puddle) - poured accelerant

explosion chemistry

• Combustion reaction

• Major differences is speed of reaction

• Damage caused by rapidly escaping gasses and confinement 

• Explosion - sudden release of chemical or mechanical energy caused by an oxidation or decomposition reaction that produces heat and a rapid expansion of gasses 

• Reagent - substance used to produce a chemical reaction to detect, measure, or produce other substances 

• High explosives

  • Chemicals that oxidize extremely rapidly, producing heat, light and a shock wave

  • These will explode even if not confined 

• Low explosives

  • Chemicals that oxidize rapidly, producing heat, light and a pressure wave

  • Will explode only when confined 

Types of explosives

low explosives, high explosives, commercial explosions, military explosions, IED

Low explosions

• Have escaping asses up to about 3000 feet per second

• Crucial element is physical mixture of oxygen and fuel

• Examples are black and smokeless powders 

  • Black powder is mixture of potassium nitrate, charcoal, and sulfur

  • Smokeless powder is nitrocellulose and perhaps nitroglycerine

High explosions

• Velocity of escaping gasses up to 10,000fps

• Oxygen usually contained in fuel molecule 

• Initiating 

  • Sensitive, will detonate readily when subjected to heat or shock

  • Used to detonate other explosives in explosive tain

• Non Initiating

  • Relatively insensitive, requires heat or shock

  • Includes TNT or PETN

Commercial explosions

• Ammonium nitrate fuel oil

• Black powder

• Dynamite

Military explosions

• RDX - commonly known as C-4

• PETN 

• PETN mixed with TNT to make grenades

IED - improvised explosive device

• Low explosives placed into confided containers

• A bomb constructed and deployed in ways other than in conventional military action 

• May be constructed of conventional military explosives such as an artillery round attached to a detonating mechanism

• Commonly used as roadside bombs