drug detection and testing

Question 1

Biological samples can be taken from

Answer 1

• Blood
• Breath = convenient
• Urine = typically in a hospital setting
• Saliva
• Hair = not very commonly done, only done if chronic use is suspected
• Identification = some sort of screening involved
• Measure levels = if trying to quantify specific levels
• If it is completely unknown, it is very difficult

Question 2

what is drug detection important in

Answer 2

DETECTION
 Detection is important in:
- Treatment
- Safety
- Anti-doping measures
- Law enforcement
- Research

Question 3

Alcohol Detection

Answer 3

 Breathalyser = quantifies alcohol content
 Limit = 0.08% BAC (breath alcohol content)
- Alcohol in breath = chemical reaction = colour test with sulphuric acid, silver nitrate and potassium dichromate
- Depending on degree of colour change = converted to electric current in meter
 Make the assumption that alcohol in breath is directly proportional to alcohol in blood
 Not a fool proof method so cannot be convicted with just this singular test
 Need a secondary test to confirm:
- Intoxilyzer uses infrared spectroscopy
- IR beam in wavelengths for chemical bonds in ethanol
- IR absorption varies depending on level of alcohol = converted to electrical signal

Question 4

Solid tests

Answer 4

qualitative

Solid tests can be used to confirm the presence of benzodiazepines, ketamine and cocaine.

based on principles of antibody binding

sample is placed in the sample inlet and dissolved with the solvent.

and moves forward by capillary action

if the drug is not present: the control dye will bind to the immobilised antibody on the line and appear as a coloured line to show that the test is working

if the drug is present it will bind to the immobilised antibody before the control dye. and no coloured line will appear

 Kit completes with swab for sample collection, buffer solutions, bottle for mixing compound and test cartridge
 Some have Home Office approval

Question 5

what are the problems with antibody binding test

Answer 5

1. Sensitivity issues- the test can detect low conc. of the drug
2. Some tests may deliever quick results however some may take longer
    With urine or blood tests: Can have sensitivity issues and detection time can be a problem as have to consider genetics of the drug and the rate of metabolism

Question 6

how does the urine test work

Answer 6

qualitative
- Test for multiple compounds
-  Allow the test to absorb the urine for about 10-15 seconds
 Remove the test from the urine and replace the test cap
 Lay the test on a clean flat surface while the test line develops
 Can read negative results as soon as they appear but positive results must be read at least 5 mins after removing from urine

Question 7

Home testing Kits

Answer 7

qualitative
A container that contains marguis reagent (conc. sulfuric acid)
- look at colour change to identify the substance.
 Not the most accurate as it is based on colours = issue when there is a mix of substances. Colour blindness, different perceptions of colour
- MDMA
- Methamphetamine,
- Morphine

Question 7

home testing kits problem

Answer 7

The problem with home testing kits is that based on colour assessment, you can not determine exactly what is in what pill.

1. ambiguity and subjectivness of colour.
2. Do not tell you about the quantity of the drug- thus not a good measure of safety.
3. Colorimetry does not provide specific identification of substances. It might indicate the presence of a certain class of drugs, but it cannot distinguish between different drugs within that class. This makes it insufficient for identifying complex mixtures accurately.

eg. In the pill, the coloromiterty test told us the pill contains mdma but not PMA

Question 7

GC-MS - gas chromatography mass spectrophotometry

Answer 7

-gas chromatography: separates the components within the drug

-mass spectrophotometry: identifies the components of the substances by comparing to known values.

• reliable
  -sensitive
• quantiative
• Allows u to screen the substance and identify all the compounds within it.

Question 7

Infrared spectroscopy

Answer 7

• This is a test that provides the convenience of a solid test and the specificity of infrared spectroscopy

-unambiguous identification
- reliable
-rapid
-portable
- no sample prep is needed

but you require an extensive library of IR spectrum on legal highs.

Question 7

where can these samples be detected

Answer 7

 Internet/headshops
- Try to order substances from the dark web to investigate on it
- Systematic screening for new compounds
- Monitor effects of new legislations
 Amnesty bins from clubs or festivals
- Search before entry, anything left in sealed container
 Police and Border Agency
- Drug testing following arrest
- Seizures
 Hospital admissions
 Questionnaires
 Waste
- Pooled urine – no female samples as they use a urinal
- Sewage

Question 7

KEEPING UP WITH MAKERS/USERS

Answer 7

 Different laws have now been introduced but before chemists used to modify structures of existing substances
 When this was then publicised in its use, detection methods began to be used and then new bans had to be put in place
 Then decided to put in a blanket ban (just ban everything) = Psychoactive Substances Act in 2016 = wasn’t effective as it is not entirely consistent
 Ended up pushing things to the black market