Drugs of Abuse Determination (Other Methods) Flashcards
Color test: The result is a purple-red color of the lower (chloroform) layer indicating the possible presence of cannabis
Fast Blue B Salt Test
This is the first reagent on Fast Blue B Salt Test (include volume)
2.5 g of fast blue B salt mixed with 100 g of anhydrous
sodium sulfate
This is the second reagent on Fast Blue B Salt Test and how many drops?
chloroform
This is the third reagent on Fast Blue B Salt Test (include volume)
0.1 N Sodium hydroxide solution
Color test: The result is violet color of the lower (chloroform) layer indicates the possible presence of cannabis
Duquenois-Levine Test
This is the first reagent on Duquenois-Levine Test (include volume)
(2 ml)
2 grams of vanillin in 100 ml of 95% ethanol with 2.5 ml acetaldehyde
(shake the test tube for one minute)
This is the second reagent on Duquenois-Levine Test (include volume)
2 ml of the second reagent (concentrated hydrochloric acid) and shake the test tube a few seconds, then allow the test tube to stand for a few minutes
This is the third reagent on Duquenois-Levine Test (include volume)
(2 ml) Chloroform
(shake the mixture gently)
The duration (minutes) of the color development in Duquenois-Levine Test before the addition of third reagent
2-3 minutes
Method that is only presumptive
Color test
Method which the Positive result should be confirmed by another test
Color test/Manualmethod
This method is used for preliminary screening
Immunoassay method
This method is based on an antibody-antigen reaction where small amounts of the drug or metabolite(s) can be detected.
Immunoassay method
In the immunoassay method, antibodies are tagged with markers. What are these markers stated in the module?
Enzyme
Radio isotope
Fluorescence
This is sometimes used as a screening method, although
it is a more labor-intensive approach.
Thin layer chromatography (TLC)
This detects the major metabolite of THC (9-carboxy-THC) in urine, along with probable cross-reactivity to many of the other metabolites of THC and their glucuronide conjugates known to be excreted in urine.
Immunoassay method
These are generally the methods of choice for the initial screening assay
Immunoassay method
Immunoassay method: This is a homogeneous enzyme immunoassay technique
EMIT Cannabinoid Assay/EMIT
Immunoassay method: This is based on competition between drug in the specimen and drug labeled with the enzyme glucose-6-phosphate dehydrogenase (G6PDH) for antibody binding sites
Enzyme Multiplied Immunoassay Technique (EMIT)
Immunoassay method: This is used for the analysis of specific compounds in human urine
EMIT
EMIT: A specimen that gives a change in rate value equal to or higher than the rate of the selected cutoff calibrator level (20 ng/mL) is interpreted as
Positive
EMIT: A specimen that gives a change in rate value lower than the rate of the selected cutoff calibrator level (20 ng/mL) is interpreted as
Negative
EMIT: Cutoff calibrator level (value)
20 ng/mL
Causes an absorbance change in EMIT
when NAD is converted into NADH by active enzyme
EMIT: positive specimen
contain cannabinoid
EMIT: negative specimen
do not contain cannabinoids,
Endogenous serum enzyme that does not cause interferences in EMIT
Glucose-6-phosphate dehydrogenase (G6PDH)
One of the most sensitive and most specific methods of immuneassays
Radioimmunoassay (RIA)
Immunoassay method: It involves the competitive binding of radio-labeled THC and the patient’s THC which are both specific to a high-affinity Anti-THC antibody.
Radioimmunoassay (RIA)
Sensitivity range of RIA
0.0006–0.006 μg antibody/ml
Immunoassay method: This is based on the competition
between THC and a THC–fluorescein tracer for a THC-specific antibody
Fluorescence Polarization Immunoassay (FPIA)
FPIA: When a fluorophore in solution is exposed to plane-polarized light at its excitation wavelength, the resulting emission is
depolarized
FPIA: Depolarization results from the motion of the fluorophore during the process of
Excitation
Emission
FPIA: the more depolarized the resulting emission, the more rapid the motion of the fluorophore is (T/F)
F, its the other way around
A commercially prepared THC is linked
covalently to the fluorophore to make a
fluorescent tracer
FPIA
In the ____ of THC, the antibody binds to
the tracer, restricting its motion and causing a
high polarization
ABSENCE
In the ____ of THC → less of the tracer is bound to the antibody and a greater fraction exists unbound in solution, in which the polarization is less
PRESENCE
FPIA: The polarization value is directly proportional to the THC concentration in the sample (T/F)
F, inversely
This is the main outcome of the chromatographic method
Separation of a mixture
The chromatography methods in current use can separate and detect more specifically
9-carboxy-THC
Chromatography method: Confirmation methods for 9-carboxy-THC include:
GLC
HPLC
TLC
Chromatography method: The confirmation methods for 9-carboxy-THC are subjected to interference from ____
co-eluting substances
Chromatography method: One of the most widely employed approaches for the analysis of cannabinoids in plant materials
Gas chromatography
Chromatography method: Operates at very high temperatures
Gas chromatography
Gas chromatography operates at very high temperatures, which unavoidably leads to the _____ of the cannabinoids
Decarboxylation
Carrier gas in gas chromatography
Helium
Nitrogen
This is where the detection takes place in gas chromatography
at the end of the heated column
2 reasons why the substance to be analyzed in gas chromatography is often “derivatized”
(1) to make it volatile
(2) to change its chromatographic characteristics
This is a form of column chromatography that pumps a sample mixture or analyte in a solvent (known as the mobile phase) at high pressure through a column with chromatographic packing material (stationary phase)
High Performance Liquid Chromatography (HPLC)
In HPLC, the sample is carried by a moving carrier gas stream of
Helium or Nitrogen
This chromatography method has the ability to separate, and identify compounds that are present in any sample that can be dissolved in a liquid in trace concentrations as low as parts per trillion
HPLC
HPLC requires a gas under high pressure to be used to flush the column (T/F)
F, liquid not gas
HPLC: Sample retention time will vary depending on the interaction between (?)
(1) the stationary phase
(2) the molecules being analyzed
(3) solvents used.
HPLC: Characteristics of an analyte to exit the column faster
(1) have the LEAST amount of interaction with the STATIONARY phase
(2) the MOST amount of interaction with the MOBILE phase
HPLC: Instrumentions
○ Solvent reservoir/multiple reservoir
○ High-pressure pump
○ Column
○ Injector system
○ Detectors
This typically measure UV light absorbance, which can be associated with specific molecules
HPLC detectors
Chromatography method: This typically measures UV light absorbance, which can be associated with specific molecules
Thin Layer Chromatography
In TLC, visual evaluation is obtained by dipping the
TLC plate into aqueous FBB solution
Chromatography method: This method can be
applied to both polar and nonpolar C18 silica
gel plates
Thin Layer Chromatography
Provides opposite elution order of the
cannabinoids
C18 silica gel plates
Limitations of Thin Layer Chromatography
Low sensitivity
Low specificity
Gold standard
Gas Chromatography/Mass Spectrometry
Combination of the two sophisticated
technologies
Gas Chromatography/Mass Spectrometry
This is the method of choice for substances that are difficult to volatilize.
HPLC/MS
Advantages of Gas Chromatography/Mass Spectrometry
sensitive
specific
able to identify all types of drugs in any body fluid
