Forensic Toxicology Jeffery Hackett MSc CChem, MRSC Center for Forensic Sciences

1
Forensic ToxicologyJeffery Hackett MSc CChem,
MRSCCenter for Forensic Sciences

• Forensic Science week

2
Outline

• Description
• Specimen Collection
• Methods of Analysis
• Reporting

3
What is forensic toxicology?

• Forensic
• Scientific methodology applied to legal
  investigations
• Toxicology
• Study of drugs/poisons and their adverse affects
  on the human system pharmacokinetics (how the
  drug works on people), pharmacodynamics (how
  people work on the drugs)

4
DFSA - Drug-Facilitated Sexual Assault
5
Recommended Texts

• Criminalistics an introduction to Forensic
  Science, Richard Saferstein.
• Principles of Forensic Toxicology Barry Levine.
• Clarkes Isolation and Identification of Drugs in
  pharmaceuticals, body fluids, and post-mortem
  material. Ed. Moffat, Jackson, Moss and Widdop.

6
Recommended Journals

• Journal of Analytical Toxicology
• Journal of Forensic Science
• Forensic Science International
• Journal of Chromatography (B)
• British Medical Journal
• Drug and Alcohol Dependence
• International Journal of Legal Medicine

7
Specimen Collection
8
What Specimens?

• Blood CSF
• Urine Vitreous Humor
• Liver Hair
• Bile Nails
• Kidney Oral Fluid
• Stomach Contents Bone
• Lungs Skin

9
Sampling

• Blood - It matters where you sample in the body -
  if blood is taken near the liver or another solid
  organ, there may be drug diffusion from the organ
  into the blood post-mortem and can give incorrect
  (very high) drug levels. Take blood from femoral
  artery (best) because its far from organs.
• Urine - tends to concentrate compounds but cant
  be sure of body concentration due to how long it
  has been accumulating in the body.
• Liver - concentrates and hold drugs for long
  times - good for detection but problematic for
  concentrations.

10
Sampling

• Bile - Useful for detection but not
  concentration.
• Kidney - Similar to Bile.
• Vitreous Humor - Correlates well with femoral
  blood for most analytes.
• Hair, Nails - Good for some analytes with
  possible timelines (relatively long).
• Oral Fluids - Can be easily disguised.
• Others - May be good for certain analyses but not
  generally good sources for many analytes.

11
Additional Matrices

• Vomit Meconium
• Earwax Amniotic Fluid
• Semen Cord Blood
• Faeces Milk
• Sweat

12
Specimen Collection

• Dependent on the type of case and what samples
  are available!

13
Case Examples

• Deceased
• Suspected drug related death
• Road Traffic Death
• Murder
• Antecedent
• Drink/drug driving

14
Case Examples (2)

• Antecedent (cont.)
• Professional/amateur athlete
• Workplace drug testing
• Arrestee
• Drug Facilitated Sexual Assault (DFSA)

15
Forensic Toxicology

• Postmortem Forensic Toxicology
• Human Performance Toxicology
• Forensic Drug Testing

16
Postmortem Forensic Toxicology

• Death Investigation
• Coroner (UK or some places in US)/Procurator
  Fiscal (Scotland) investigates sudden or
  unexplained deaths (actual judges).
• Medical Examiners Office (US).
• NYS - elected corners or appointed Med. Examiners
  depending upon county.
• Forensic Pathologist responsible for performing
  autopsy
• Forensic Toxicologist responsible for analysing
  biological samples for poisons

17
Specimen Acquisition

• Essential to collect the appropriate specimens
  and that they are collected correctly
• Pathologist is responsible for the collection of
  the specimens and may consult the toxicologist
  with unusual cases

18
REMINDER Sampling

• MOST IMPORTANT STEP!!!!
• Representative Sample
• A portion of a material taken from a
  consignment and selected in such a way that it
  possesses the essential characteristics of the
  bulk.

19
Sample Preparation

• Homogenising
• grind (mortar and pestle)
• blender
• dissolution (water, solvents, acids)

20
Sample Handling

• Storage
• Avoid - loss (due to volatility)
• - contamination (e.g., insufficient seal)
• Prevent - chemical interactions (e.g., Na and
  oil)
• - Degradation (refrigerate biological
  samples)

21
Postmortem Forensic Toxicology

• Blood Samples
• Most important specimen
• Ideally 2 samples (25 mL)
• Femoral/jugular (peripheral site)
• Heart blood
• Trunk blood ????

22
Postmortem Forensic Toxicology

• Vitreous humor samples
• Should be collected at all PMs
• Relatively stable matrix
• Anatomically isolated area
• Good correlation with blood
• Easily obtained

23
Postmortem Forensic Toxicology

• Urine samples
• All available sample should be collected
• Higher concentrations present than other
  matrices, but not always
• Rapid tests available (colorimetric tests)
• Not always available

24
Postmortem Forensic Toxicology

• Bile samples
• Alternative if urine unavailable
• Accumulation of drugs
• All available bile should be collected
• Not an easy sample to analyze

25
Postmortem Forensic Toxicology

• Liver samples
• Drug metabolism occurs in the liver
• Drugs may be present in higher concentrations
• Some ideas about being difficult to analyze

26
Postmortem Forensic Toxicology

• Other specimens
• Lung (volatiles)
• Spleen (carbon monoxide) blood unavailable
• Stomach Contents (drug overdose)
• Hair ( drug use history)

27
Human Performance Toxicology

• The effects of drugs on skills, acquisition,
  learning, and performance
• Drugs may alter normal behaviour by either
  enhancing or impairing performance
• Stimulant drugs can enhance performance short
  term but used regularly can impair performance

28
Human Performance Toxicology

• Not only illicit drugs (e.g. heroin, cocaine,
  cannabis)
• Prescription medication can impair performance
  especially at the start of the treatment
• E.g. antidepressants, muscle relaxants

29
Human Performance Toxicology

• Blood is the best specimen for determining
  impairment through drugs
• In contact with the central nervous system
• Hair/urine/sweat becoming popular but unlikely
  that a direct relationship will exist

30
Human Performance Toxicology

• Alcohol /or Drugs Driving
• In addition to collecting the correct samples,
  additional information is essential
• Witness statements to the incident
• Assessment of impairment at the scene
• Field Sobriety tests
• Drug Recognition Evaluation

31
Human Performance Toxicology

• Specimen Acquisition
• Breath Test (alcohol)
• Blood sample (alcohol and drugs)
• Urine sample (alcohol and drugs)

32
Human Performance Toxicology

• Collection
• Breath police officer at the scene
• Blood must be obtained by a medic (police
  surgeon or forensic medical examiner - FME (UK))
• Urine collection must be observed

33
Forensic Drug Testing

• Workplace Drug Testing
• Armed forces
• Prisons
• Private and public companies
• Schools
• International Olympic Committee
• Athletes

34
Forensic Drug Testing

• Police Investigations
• Arrestee
• Drug Facilitated Sexual Assault (DFSA)

35
Forensic Toxicology

• What specimen ? ?
• Storage
• Chain of Custody
• Analysis
• Reporting

36
Forensic Toxicology

• Storage
• Fridge/freezer
• Preservative
• Leak proof
• Suitable size
• Prevent contamination

37
Forensic Toxicology

• What specimen ? ?
• Storage ?
• Chain of Custody
• Analysis
• Reporting

38
Forensic Toxicology

• Chain of Custody
• Extremely important, without this the results
  would not be admissible in court
• Ensure procedures have been followed, seals
  intact, signatures checked etc..

39
(No Transcript)
40
Forensic Toxicology

• What specimen ? ?
• Storage ?
• Chain of Custody ?
• Analysis
• Reporting

41
Paracelsus

• What is there that is not a poison? All things
  are poison and nothing without poison. Solely the
  dose determines that a thing is not a poison.

42
Analysis

• Volatiles Head Space GC

43
Immunoassay

• Presently
• EMIT.Good for Urines, Limited Scope
• RIA.Good for Serum.Problem
• ELISA/FPIA.Handle Tissues/Extended Scope

44
Confirmation/Quantitation

• Validated Method Detailed SOP
• Extraction Procedure
• Chromatography
• Gas Liquid.Liquid
• Mass Spectrometry

45
Liquid Chromatography
46
GC-MS
31.73
33.71
42.18
19.17
46.23
53.91
41.44
47.20
42.98
47
What drugs are we looking at
48
Reporting

Relationship of blood/urine alcohol

levels of blood/tissue drugs

What do the
metabolites
indicate

involvement of alcohol/drugs

Opiates
What do free/ total opiate levels indicate
49
(No Transcript)
50
(No Transcript)
51
Where does it end up

• UK
• Crown Court
• Magistrates Court
• Coroners Court
• US
• Medical Examiner
• County Court

52
Thanks

• Any Questions