7 - Drug Testing Flashcards
What are the different matrices for drug testing?
Blood
Oral fluid
Sweat
Hair
Urine
Pros and cons of blood as a matrice
+ hard to cheat/adulterate
+ recent use of drug
- invasive
- low concentration, disappears quickly
- special facilities, costly & complex
Pros and cons of oral fluid as a matrice
+ easy to collect & test
+ hard to cheat
+ range of drugs
+ test kits
- limited sample size
- low concentration, doesn’t work on certain drugs
- not representative of blood concentration e.g. smoking
Pros and cons of sweat as a matrice
+ easy to collect, test kits
+ sweat collection patches monitor history
- expensive testing
- small sample, easily contaminated
- hard to interpret
Pros and cons of hair as a matrice
+ long history
+ stable
+ range of drugs
+ useful on corpses
- easily contaminated
- affected by hair treatment e.g. dyeing
- racial bias & people prone to getting haircuts
Pros and cons of hyphenated techniques
+ fast, accurate, confirmatory
+ high reproducibility, selectivity, sensitivity
+ lowered chance of sample contamination
- expensive, high storage space needed due to lots of data
- difficult to isolate occurrence/route of contamination
What is the role of chromatography in a hyphenated technique?
Separates samples
What is the role of spectroscopy in a hyphenated technique?
Confirms identity/presence of drugs
Name a pro of LC-MS
+ no need for derivatisation due to low temperatures
Pros and cons of GC
+ high resolution
+ quick & easy
+ sensitive and accurate
+ quantitative
- samples must be volatile & stable at high temperatures
- samples may need derivatisation
- multiple retention times for confirmation
HPLC characteristics
- solute must be soluble in mobile phase
- can analyse ionic compounds
- molecular size doesn’t matter
- shorter columns than GC
What is tandem MS?
- 2 mass spectrometers
- 1st MS analyses normally (fires electrons to ionise sample & fragment it, pulls it through electromagnetic field, samples reach detector based on m/z ratio, spectra created)
- 2nd MS analyses specific ion. ‘Unclean’ part of spectra isolated (specific ion) and it put into fragment collision cell - fragments produce further fragments when colliding with argon - further fragments analysed by 2nd MS to produce cleaner spectra
What are bath salts? Name their aliases
- Synthetic compounds, similar effect to amphetamine & cocaine
Ivory wave
Vanilla sky
Plant food
What are the two types of breathalysers? How do they work?
Fuel cell:
- Alcohol oxidised, electrons release, electrical current created which is proportional to quantity of alcohol present in breath
Infra red:
- Measures absorption of light by potassium dichromate. Low light intensity at particular wavenumber proportion to concentration of alcohol in breath
Pros and cons of fuel cell breathalyser
+ high sensitivity to ethanol
+ portable
- results affected by acetone & CO
