Download - OSBI Toxicology Lab
OSBI Toxicology LabCurrent Technologies
for Blood Testing
Robert G. WestonForensic Toxicologist
We are… Seven full-time toxicologists One part-time technician Combined 90 years of tox experience
What law enforcement officers do…
Recent DUI caseload DUI cases submitted:
2011 – 3987 cases 2010 – 3951 cases 2009 – 3854 cases 2008 – 3768 cases 2007 – 3217 cases
Unlike CSI, we… must separate the drugs from the blood through sample
preparation. set up the analysis and wait for the data to be collected. review and interpret the data. do not know everything about every drug seen in the blood. determine the identity of substances we haven’t seen before. do not have a universal test that is effective for all drugs.
Everyone knows how drugs get in…
…but how do we get them out???
Composition of blood Red blood cells (40-50% of blood volume) White blood cells (1 % of blood volume) Platelets Plasma
• Water (>92%)• Sugars
• Lipids• Vitamins• Minerals
• Hormones• Enzymes• Antibodies• Proteins
Volatiles analysis Blood placed into a vial Internal standard is added Vial is heated Only volatile components evaporate into the headspace
Alcohols (ethanol, methanol, isopropyl) Acetone Toluene Difluoroethane (from spray dusters)
Volatiles analysis A portion of the headspace gas is introduced into a gas chromatograph
Comparison is made between the sample and known standards
Quantification of ethanol
Identification of other volatiles
ELISAEnzyme-linked immunosorbent assay
ELISA Presumptive for classes of compounds Eight classes currently tested for are
Barbiturates Benzodiazepines Carisoprodol/meprobamate Cocaine/benzoylecgonine Phencyclidine Phenethylamines (meth) Opiates Tetrahydrocannabinols (marijauna)
Results must be confirmed by a chromatography/mass spectrometry method
At OSBI, all confirmatory testingin toxicology involves…
CHROMATOGRAPHY
The separation process
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Alkaline drug analysis2 milliliters of blood+internal standards+borate buffer+n-butyl chloride+mixing+centrifuging DRUGS
MOVE
Alkaline drug analysis
• Transfer top layer to new tube
• Add hydrochloric acid
• Mix
• Centrifuge
DRUGS MOVE
Alkaline drug analysis
• Dispose of top layer• Add sodium hydroxide• Mix• Add chloroform• Mix• Centrifuge• Transfer chloroform to vial
Gas chromatography mass spectrometry
Why negative results?
Not all drugs extract well Drug may be present in an amount less
than what our methods can detect
Some drugs metabolize very quickly We don’t have methods to test for every
drug
New technology for OSBI
LC/MS/MS Advantages
Less sample needed Less sample prep (generally) Lower limits of detection Now capable of detecting previously unseen drugs
• 2.0 milliliters of blood for GC/MS testing
• 0.2 milliliters of blood for LC/MS/MS testing
Blank blood
New analysis capability - SPICE• Seven synthetic
cannabinoids
• 0.5 ng/mL
• AM-2201
• JWH-018
• JWH-073
• JWH-081
• JWH-122
• JWH-210
• JWH-250
3.0 minutes!!
A case sample – AM-2201 found on driver and in blood
AM-2201
Small amounts of other “spice” compounds.
What else can we do?
• 12 benzodiazepines
• Under 4 minutes
• Limit of detection: 5 ng/mL
An real case example.
ELISA positive for benzos, but none found
Temazepam would be found here.
Now we can see…
oxazepam
temazepam
Why lower limits of detection? Fewer steps in sample prep – fewer
opportunities to “lose” drugs.
We can program the instrument to “see” only the drugs we are interested in.
Other drugs/chemicals present do not cause a response.
High concentrations of other drugs
Blank Opiates Mix
High concentrations of other drugs
Blank THCs Mix
High concentrations of other drugs
Blank Spice Mix
LC/MS/MS limitations Limited to analyzing what we have validated Method validation time consuming Not currently set up for unknown screening Different methods for different compounds –
multiple analyses required for multiple compound types
We will be able to analyze for most drugs with LC/MS/MS – it is just a matter of time
Upcoming projects
Continue to expand capacities Opiates More synthetic cannabinoids “Bath salts” Cocaine
Quantitations