Drug Checking Flashcards
How long is the warm up phase for the FTIR machine?
10 minutes - bar will no longer be green on opus
Calibrating the FTIR to environment ensures what?
Measurements are cleaner and there’s less noise in the measured spectra
What does PQ mean? Should be done when?
Performance Qualification- calibration test
•must be done weekly
•should be done every time the machine is moved locations
How to run PQ test?
- Click status light (green) at the bottom right corner of the screen (on opus)
- Select accessory type
- Select PQ Test
- Select Run Test
- Takes 5 mins light will turn green when done
What is the 1st step of every drug check? And why?
Background Scan - click “measure background” on left hand side
Zeroes the sensor to prepare for the sample scan (just a like a scale) - must be done immediately before loading the sample
How many mg for testing?
5mg
What to do after background scan is done?
- Click “measure sample” on left hand side of screen
- Insert sample information
- Make sure line is flat
- Put drugs on the sensor
- Lower handle slowly
- When graph is past 0.3 click “start measurement” - bottom left
What is the format of the naming convention?
0 [site identifier]
MM [month of test]
DD [day of test]
YY [year of test]
## [daily sample number]
II [technician initials]
Graph should reach what level on the y axis?
Over 0.3
Samples are measured with how many scans?
24 scans - takes 24 seconds
Why is calibration important?
Because it’s sensitive to temperature and humidity so we need to account for those factors
3 reasons why we must clean the spectrometer after every sample?
- No cross contamination
- Ensure each measurement is representative of the respective sample
- Background scan will need to be performed for the next sample
Spectra is caused by infrared light
A) absorbed causing a peak
B) not absorbed causes a flat line
Definition of Spectra
Graphical representations of the sample’s chemical composition
X axis is the
Wave number
Representation of the frequency infrared light that is either absorbed (peak) or not absorbed (flat line)
Drug analyzing
- Load file in - button top right corner
- Press “spectrum search” - red magnify glass
- Perform subtractive analysis
[spectrum search, search parameters, select libraries] - Perform mixture analysis
Two-step process
- Subtractive analysis - identifies components
- Mixture analysis - assigns approximate proportions
Spectrum search know how
- Spectrum Search Tab: Use file limits - searches entire spectra image
- Search Parameters: select which analysis type and algorithms to use
- Select libraries: select which reference libraries you want to search your spectrum against
Subtractive analysis know how
- Spectrum Search
- Search parameters -
a) spectrum correlation
b) vector normalization
c) 1st derivative - Search libraries - 3 primary ones
What are the 3 primary libraries
- SWGDRUG
- TICTAC
- BCCSU
Definition of Hit Quality? What does score represent?
A score out of 1,000 that ranks how well the searched spectrum correlates to the library entry
High scores are better but the number itself does not mean too much.
The red spectrum is…?
The one we measured and the one we are working with
How to drag peaks up and down to evaluate how well the spectra match
- In window right click “shift curve”
- Hit “top”
How to evaluate for other agents in spectra sample by removing primary signal?
- Right click on the library entry of primary signal
- Click “auto subtract and new search”
What happens if two compounds both have peaks at the same wave number?
If two compounds both have peaks at the same wave number, the spectrometer can’t tell which compound is responsible for that absorption
What is composite spectrum
The result after the algorithm breaks down the measured spectrum and tries to re-create it with the library entries
Displayed with percentage make up of signal
Mixture Analysis
Mixture Analysis know how
- Return to 1st tab where original spectrum
- “Spectrum Search” - red magnify glass
- Search parameters select
a) mixture analysis on right hand side
b) select “expected number of components” - Select libraries (typically only 1 BCCSU)
- Click “Search library” bottom left corner
How to close a tab?
When a tab is open you can click “x” on the right hand side to close it and press “discard changes”
What is the residual
The difference between the red and purple lines (mixture analysis)
Drawbacks from mixture analysis (3)
- Will often not return results for components present at less than 10%
- Will often return false results that you did not detect during subtractions
- Different search parameters will affect the outcome (ie: libraries)
Golden rule of mixture analysis
Never immediately believe a result reported in mixture analysis that wasn’t first detected during subtractions
DCBC Steps
- Select site location
- Brings you to home page
- Left hand side - “Visit Summary”
- Click “new visit” - top right hand corner
- Click “add sample”
a) pre check
b) FTIR check
c) post check
A) Pre check log info
- Expected drug
- Pre or post use
- Colour and texture
- Results
Why is it important to collect drug checking data?
Drug checking data provides timely information about local drug markets in British Columbia
How many components can the FTIR detect?
Up to 4
Greeting service user important things to cover
- The two technologies we use.
- The limit of detection of the FTIR and why we use the test strips to overcome this
- That a few grains of their sample will be dissolved in water for the test strips.
- The length of time the test will take.
** make sure to receive verbal consent to proceed**
Questions to ask the service user
- Do you have any questions about the disclaimer or the procedure before we begin?
- How many drugs are you wanting to check today?
- What did you purchase this sample as?
- Have you tried the sample yet?
